<reponame>jtyuan/racetrack<filename>src/arch/isa_parser.py
# Copyright (c) 2003-2005 The Regents of The University of Michigan
# Copyright (c) 2013 Advanced Micro Devices, Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met: redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer;
# redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution;
# neither the name of the copyright holders nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# Authors: <NAME>

from __future__ import with_statement
import os
import sys
import re
import string
import inspect, traceback
# get type names
from types import *

from m5.util.grammar import Grammar

debug=False

###################
# Utility functions

#
# Indent every line in string 's' by two spaces
# (except preprocessor directives).
# Used to make nested code blocks look pretty.
#
def indent(s):
    return re.sub(r'(?m)^(?!#)', '  ', s)

#
# Munge a somewhat arbitrarily formatted piece of Python code
# (e.g. from a format 'let' block) into something whose indentation
# will get by the Python parser.
#
# The two keys here are that Python will give a syntax error if
# there's any whitespace at the beginning of the first line, and that
# all lines at the same lexical nesting level must have identical
# indentation.  Unfortunately the way code literals work, an entire
# let block tends to have some initial indentation.  Rather than
# trying to figure out what that is and strip it off, we prepend 'if
# 1:' to make the let code the nested block inside the if (and have
# the parser automatically deal with the indentation for us).
#
# We don't want to do this if (1) the code block is empty or (2) the
# first line of the block doesn't have any whitespace at the front.

def fixPythonIndentation(s):
    # get rid of blank lines first
    s = re.sub(r'(?m)^\s*\n', '', s);
    if (s != '' and re.match(r'[ \t]', s[0])):
        s = 'if 1:\n' + s
    return s

class ISAParserError(Exception):
    """Error handler for parser errors"""
    def __init__(self, first, second=None):
        if second is None:
            self.lineno = 0
            self.string = first
        else:
            if hasattr(first, 'lexer'):
                first = first.lexer.lineno
            self.lineno = first
            self.string = second

    def display(self, filename_stack, print_traceback=debug):
        # Output formatted to work under Emacs compile-mode.  Optional
        # 'print_traceback' arg, if set to True, prints a Python stack
        # backtrace too (can be handy when trying to debug the parser
        # itself).

        spaces = ""
        for (filename, line) in filename_stack[:-1]:
            print "%sIn file included from %s:" % (spaces, filename)
            spaces += "  "

        # Print a Python stack backtrace if requested.
        if print_traceback or not self.lineno:
            traceback.print_exc()

        line_str = "%s:" % (filename_stack[-1][0], )
        if self.lineno:
            line_str += "%d:" % (self.lineno, )

        return "%s%s %s" % (spaces, line_str, self.string)

    def exit(self, filename_stack, print_traceback=debug):
        # Just call exit.

        sys.exit(self.display(filename_stack, print_traceback))

def error(*args):
    raise ISAParserError(*args)

####################
# Template objects.
#
# Template objects are format strings that allow substitution from
# the attribute spaces of other objects (e.g. InstObjParams instances).

labelRE = re.compile(r'(?<!%)%\(([^\)]+)\)[sd]')

class Template(object):
    def __init__(self, parser, t):
        self.parser = parser
        self.template = t

    def subst(self, d):
        myDict = None

        # Protect non-Python-dict substitutions (e.g. if there's a printf
        # in the templated C++ code)
        template = self.parser.protectNonSubstPercents(self.template)
        # CPU-model-specific substitutions are handled later (in GenCode).
        template = self.parser.protectCpuSymbols(template)

        # Build a dict ('myDict') to use for the template substitution.
        # Start with the template namespace.  Make a copy since we're
        # going to modify it.
        myDict = self.parser.templateMap.copy()

        if isinstance(d, InstObjParams):
            # If we're dealing with an InstObjParams object, we need
            # to be a little more sophisticated.  The instruction-wide
            # parameters are already formed, but the parameters which
            # are only function wide still need to be generated.
            compositeCode = ''

            myDict.update(d.__dict__)
            # The "operands" and "snippets" attributes of the InstObjParams
            # objects are for internal use and not substitution.
            del myDict['operands']
            del myDict['snippets']

            snippetLabels = [l for l in labelRE.findall(template)
                             if d.snippets.has_key(l)]

            snippets = dict([(s, self.parser.mungeSnippet(d.snippets[s]))
                             for s in snippetLabels])

            myDict.update(snippets)

            compositeCode = ' '.join(map(str, snippets.values()))

            # Add in template itself in case it references any
            # operands explicitly (like Mem)
            compositeCode += ' ' + template

            operands = SubOperandList(self.parser, compositeCode, d.operands)

            myDict['op_decl'] = operands.concatAttrStrings('op_decl')
            if operands.readPC or operands.setPC:
                myDict['op_decl'] += 'TheISA::PCState __parserAutoPCState;\n'

            # In case there are predicated register reads and write, declare
            # the variables for register indicies. It is being assumed that
            # all the operands in the OperandList are also in the
            # SubOperandList and in the same order. Otherwise, it is
            # expected that predication would not be used for the operands.
            if operands.predRead:
                myDict['op_decl'] += 'uint8_t _sourceIndex = 0;\n'
            if operands.predWrite:
                myDict['op_decl'] += 'uint8_t M5_VAR_USED _destIndex = 0;\n'

            is_src = lambda op: op.is_src
            is_dest = lambda op: op.is_dest

            myDict['op_src_decl'] = \
                      operands.concatSomeAttrStrings(is_src, 'op_src_decl')
            myDict['op_dest_decl'] = \
                      operands.concatSomeAttrStrings(is_dest, 'op_dest_decl')
            if operands.readPC:
                myDict['op_src_decl'] += \
                    'TheISA::PCState __parserAutoPCState;\n'
            if operands.setPC:
                myDict['op_dest_decl'] += \
                    'TheISA::PCState __parserAutoPCState;\n'

            myDict['op_rd'] = operands.concatAttrStrings('op_rd')
            if operands.readPC:
                myDict['op_rd'] = '__parserAutoPCState = xc->pcState();\n' + \
                                  myDict['op_rd']

            # Compose the op_wb string. If we're going to write back the
            # PC state because we changed some of its elements, we'll need to
            # do that as early as possible. That allows later uncoordinated
            # modifications to the PC to layer appropriately.
            reordered = list(operands.items)
            reordered.reverse()
            op_wb_str = ''
            pcWbStr = 'xc->pcState(__parserAutoPCState);\n'
            for op_desc in reordered:
                if op_desc.isPCPart() and op_desc.is_dest:
                    op_wb_str = op_desc.op_wb + pcWbStr + op_wb_str
                    pcWbStr = ''
                else:
                    op_wb_str = op_desc.op_wb + op_wb_str
            myDict['op_wb'] = op_wb_str

        elif isinstance(d, dict):
            # if the argument is a dictionary, we just use it.
            myDict.update(d)
        elif hasattr(d, '__dict__'):
            # if the argument is an object, we use its attribute map.
            myDict.update(d.__dict__)
        else:
            raise TypeError, "Template.subst() arg must be or have dictionary"
        return template % myDict

    # Convert to string.  This handles the case when a template with a
    # CPU-specific term gets interpolated into another template or into
    # an output block.
    def __str__(self):
        return self.parser.expandCpuSymbolsToString(self.template)

################
# Format object.
#
# A format object encapsulates an instruction format.  It must provide
# a defineInst() method that generates the code for an instruction
# definition.

class Format(object):
    def __init__(self, id, params, code):
        self.id = id
        self.params = params
        label = 'def format ' + id
        self.user_code = compile(fixPythonIndentation(code), label, 'exec')
        param_list = string.join(params, ", ")
        f = '''def defInst(_code, _context, %s):
                my_locals = vars().copy()
                exec _code in _context, my_locals
                return my_locals\n''' % param_list
        c = compile(f, label + ' wrapper', 'exec')
        exec c
        self.func = defInst

    def defineInst(self, parser, name, args, lineno):
        parser.updateExportContext()
        context = parser.exportContext.copy()
        if len(name):
            Name = name[0].upper()
            if len(name) > 1:
                Name += name[1:]
        context.update({ 'name' : name, 'Name' : Name })
        try:
            vars = self.func(self.user_code, context, *args[0], **args[1])
        except Exception, exc:
            if debug:
                raise
            error(lineno, 'error defining "%s": %s.' % (name, exc))
        for k in vars.keys():
            if k not in ('header_output', 'decoder_output',
                         'exec_output', 'decode_block'):
                del vars[k]
        return GenCode(parser, **vars)

# Special null format to catch an implicit-format instruction
# definition outside of any format block.
class NoFormat(object):
    def __init__(self):
        self.defaultInst = ''

    def defineInst(self, parser, name, args, lineno):
        error(lineno,
              'instruction definition "%s" with no active format!' % name)

###############
# GenCode class
#
# The GenCode class encapsulates generated code destined for various
# output files.  The header_output and decoder_output attributes are
# strings containing code destined for decoder.hh and decoder.cc
# respectively.  The decode_block attribute contains code to be
# incorporated in the decode function itself (that will also end up in
# decoder.cc).  The exec_output attribute is a dictionary with a key
# for each CPU model name; the value associated with a particular key
# is the string of code for that CPU model's exec.cc file.  The
# has_decode_default attribute is used in the decode block to allow
# explicit default clauses to override default default clauses.

class GenCode(object):
    # Constructor.  At this point we substitute out all CPU-specific
    # symbols.  For the exec output, these go into the per-model
    # dictionary.  For all other output types they get collapsed into
    # a single string.
    def __init__(self, parser,
                 header_output = '', decoder_output = '', exec_output = '',
                 decode_block = '', has_decode_default = False):
        self.parser = parser
        self.header_output = parser.expandCpuSymbolsToString(header_output)
        self.decoder_output = parser.expandCpuSymbolsToString(decoder_output)
        self.exec_output = exec_output
        self.decode_block = decode_block
        self.has_decode_default = has_decode_default

    # Write these code chunks out to the filesystem.  They will be properly
    # interwoven by the write_top_level_files().
    def emit(self):
        if self.header_output:
            self.parser.get_file('header').write(self.header_output)
        if self.decoder_output:
            self.parser.get_file('decoder').write(self.decoder_output)
        if self.exec_output:
            self.parser.get_file('exec').write(self.exec_output)
        if self.decode_block:
            self.parser.get_file('decode_block').write(self.decode_block)

    # Override '+' operator: generate a new GenCode object that
    # concatenates all the individual strings in the operands.
    def __add__(self, other):
        return GenCode(self.parser,
                       self.header_output + other.header_output,
                       self.decoder_output + other.decoder_output,
                       self.exec_output + other.exec_output,
                       self.decode_block + other.decode_block,
                       self.has_decode_default or other.has_decode_default)

    # Prepend a string (typically a comment) to all the strings.
    def prepend_all(self, pre):
        self.header_output = pre + self.header_output
        self.decoder_output  = pre + self.decoder_output
        self.decode_block = pre + self.decode_block
        self.exec_output  = pre + self.exec_output

    # Wrap the decode block in a pair of strings (e.g., 'case foo:'
    # and 'break;').  Used to build the big nested switch statement.
    def wrap_decode_block(self, pre, post = ''):
        self.decode_block = pre + indent(self.decode_block) + post

#####################################################################
#
#                      Bitfield Operator Support
#
#####################################################################

bitOp1ArgRE = re.compile(r'<\s*(\w+)\s*:\s*>')

bitOpWordRE = re.compile(r'(?<![\w\.])([\w\.]+)<\s*(\w+)\s*:\s*(\w+)\s*>')
bitOpExprRE = re.compile(r'\)<\s*(\w+)\s*:\s*(\w+)\s*>')

def substBitOps(code):
    # first convert single-bit selectors to two-index form
    # i.e., <n> --> <n:n>
    code = bitOp1ArgRE.sub(r'<\1:\1>', code)
    # simple case: selector applied to ID (name)
    # i.e., foo<a:b> --> bits(foo, a, b)
    code = bitOpWordRE.sub(r'bits(\1, \2, \3)', code)
    # if selector is applied to expression (ending in ')'),
    # we need to search backward for matching '('
    match = bitOpExprRE.search(code)
    while match:
        exprEnd = match.start()
        here = exprEnd - 1
        nestLevel = 1
        while nestLevel > 0:
            if code[here] == '(':
                nestLevel -= 1
            elif code[here] == ')':
                nestLevel += 1
            here -= 1
            if here < 0:
                sys.exit("Didn't find '('!")
        exprStart = here+1
        newExpr = r'bits(%s, %s, %s)' % (code[exprStart:exprEnd+1],
                                         match.group(1), match.group(2))
        code = code[:exprStart] + newExpr + code[match.end():]
        match = bitOpExprRE.search(code)
    return code


#####################################################################
#
#                             Code Parser
#
# The remaining code is the support for automatically extracting
# instruction characteristics from pseudocode.
#
#####################################################################

# Force the argument to be a list.  Useful for flags, where a caller
# can specify a singleton flag or a list of flags.  Also usful for
# converting tuples to lists so they can be modified.
def makeList(arg):
    if isinstance(arg, list):
        return arg
    elif isinstance(arg, tuple):
        return list(arg)
    elif not arg:
        return []
    else:
        return [ arg ]

class Operand(object):
    '''Base class for operand descriptors.  An instance of this class
    (or actually a class derived from this one) represents a specific
    operand for a code block (e.g, "Rc.sq" as a dest). Intermediate
    derived classes encapsulates the traits of a particular operand
    type (e.g., "32-bit integer register").'''

    def buildReadCode(self, func = None):
        subst_dict = {"name": self.base_name,
                      "func": func,
                      "reg_idx": self.reg_spec,
                      "ctype": self.ctype}
        if hasattr(self, 'src_reg_idx'):
            subst_dict['op_idx'] = self.src_reg_idx
        code = self.read_code % subst_dict
        return '%s = %s;\n' % (self.base_name, code)

    def buildWriteCode(self, func = None):
        subst_dict = {"name": self.base_name,
                      "func": func,
                      "reg_idx": self.reg_spec,
                      "ctype": self.ctype,
                      "final_val": self.base_name}
        if hasattr(self, 'dest_reg_idx'):
            subst_dict['op_idx'] = self.dest_reg_idx
        code = self.write_code % subst_dict
        return '''
        {
            %s final_val = %s;
            %s;
            if (traceData) { traceData->setData(final_val); }
        }''' % (self.dflt_ctype, self.base_name, code)

    def __init__(self, parser, full_name, ext, is_src, is_dest):
        self.full_name = full_name
        self.ext = ext
        self.is_src = is_src
        self.is_dest = is_dest
        # The 'effective extension' (eff_ext) is either the actual
        # extension, if one was explicitly provided, or the default.
        if ext:
            self.eff_ext = ext
        elif hasattr(self, 'dflt_ext'):
            self.eff_ext = self.dflt_ext

        if hasattr(self, 'eff_ext'):
            self.ctype = parser.operandTypeMap[self.eff_ext]

    # Finalize additional fields (primarily code fields).  This step
    # is done separately since some of these fields may depend on the
    # register index enumeration that hasn't been performed yet at the
    # time of __init__(). The register index enumeration is affected
    # by predicated register reads/writes. Hence, we forward the flags
    # that indicate whether or not predication is in use.
    def finalize(self, predRead, predWrite):
        self.flags = self.getFlags()
        self.constructor = self.makeConstructor(predRead, predWrite)
        self.op_decl = self.makeDecl()

        if self.is_src:
            self.op_rd = self.makeRead(predRead)
            self.op_src_decl = self.makeDecl()
        else:
            self.op_rd = ''
            self.op_src_decl = ''

        if self.is_dest:
            self.op_wb = self.makeWrite(predWrite)
            self.op_dest_decl = self.makeDecl()
        else:
            self.op_wb = ''
            self.op_dest_decl = ''

    def isMem(self):
        return 0

    def isReg(self):
        return 0

    def isFloatReg(self):
        return 0

    def isIntReg(self):
        return 0

    def isCCReg(self):
        return 0

    def isControlReg(self):
        return 0

    def isPCState(self):
        return 0

    def isPCPart(self):
        return self.isPCState() and self.reg_spec

    def hasReadPred(self):
        return self.read_predicate != None

    def hasWritePred(self):
        return self.write_predicate != None

    def getFlags(self):
        # note the empty slice '[:]' gives us a copy of self.flags[0]
        # instead of a reference to it
        my_flags = self.flags[0][:]
        if self.is_src:
            my_flags += self.flags[1]
        if self.is_dest:
            my_flags += self.flags[2]
        return my_flags

    def makeDecl(self):
        # Note that initializations in the declarations are solely
        # to avoid 'uninitialized variable' errors from the compiler.
        return self.ctype + ' ' + self.base_name + ' = 0;\n';

class IntRegOperand(Operand):
    def isReg(self):
        return 1

    def isIntReg(self):
        return 1

    def makeConstructor(self, predRead, predWrite):
        c_src = ''
        c_dest = ''

        if self.is_src:
            c_src = '\n\t_srcRegIdx[_numSrcRegs++] = %s;' % (self.reg_spec)
            if self.hasReadPred():
                c_src = '\n\tif (%s) {%s\n\t}' % \
                        (self.read_predicate, c_src)

        if self.is_dest:
            c_dest = '\n\t_destRegIdx[_numDestRegs++] = %s;' % \
                    (self.reg_spec)
            c_dest += '\n\t_numIntDestRegs++;'
            if self.hasWritePred():
                c_dest = '\n\tif (%s) {%s\n\t}' % \
                         (self.write_predicate, c_dest)

        return c_src + c_dest

    def makeRead(self, predRead):
        if (self.ctype == 'float' or self.ctype == 'double'):
            error('Attempt to read integer register as FP')
        if self.read_code != None:
            return self.buildReadCode('readIntRegOperand')

        int_reg_val = ''
        if predRead:
            int_reg_val = 'xc->readIntRegOperand(this, _sourceIndex++)'
            if self.hasReadPred():
                int_reg_val = '(%s) ? %s : 0' % \
                              (self.read_predicate, int_reg_val)
        else:
            int_reg_val = 'xc->readIntRegOperand(this, %d)' % self.src_reg_idx

        return '%s = %s;\n' % (self.base_name, int_reg_val)

    def makeWrite(self, predWrite):
        if (self.ctype == 'float' or self.ctype == 'double'):
            error('Attempt to write integer register as FP')
        if self.write_code != None:
            return self.buildWriteCode('setIntRegOperand')

        if predWrite:
            wp = 'true'
            if self.hasWritePred():
                wp = self.write_predicate

            wcond = 'if (%s)' % (wp)
            windex = '_destIndex++'
        else:
            wcond = ''
            windex = '%d' % self.dest_reg_idx

        wb = '''
        %s
        {
            %s final_val = %s;
            xc->setIntRegOperand(this, %s, final_val);\n
            if (traceData) { traceData->setData(final_val); }
        }''' % (wcond, self.ctype, self.base_name, windex)

        return wb

class FloatRegOperand(Operand):
    def isReg(self):
        return 1

    def isFloatReg(self):
        return 1

    def makeConstructor(self, predRead, predWrite):
        c_src = ''
        c_dest = ''

        if self.is_src:
            c_src = '\n\t_srcRegIdx[_numSrcRegs++] = %s + FP_Reg_Base;' % \
                    (self.reg_spec)

        if self.is_dest:
            c_dest = \
              '\n\t_destRegIdx[_numDestRegs++] = %s + FP_Reg_Base;' % \
              (self.reg_spec)
            c_dest += '\n\t_numFPDestRegs++;'

        return c_src + c_dest

    def makeRead(self, predRead):
        bit_select = 0
        if (self.ctype == 'float' or self.ctype == 'double'):
            func = 'readFloatRegOperand'
        else:
            func = 'readFloatRegOperandBits'
        if self.read_code != None:
            return self.buildReadCode(func)

        if predRead:
            rindex = '_sourceIndex++'
        else:
            rindex = '%d' % self.src_reg_idx

        return '%s = xc->%s(this, %s);\n' % \
            (self.base_name, func, rindex)

    def makeWrite(self, predWrite):
        if (self.ctype == 'float' or self.ctype == 'double'):
            func = 'setFloatRegOperand'
        else:
            func = 'setFloatRegOperandBits'
        if self.write_code != None:
            return self.buildWriteCode(func)

        if predWrite:
            wp = '_destIndex++'
        else:
            wp = '%d' % self.dest_reg_idx
        wp = 'xc->%s(this, %s, final_val);' % (func, wp)

        wb = '''
        {
            %s final_val = %s;
            %s\n
            if (traceData) { traceData->setData(final_val); }
        }''' % (self.ctype, self.base_name, wp)
        return wb

class CCRegOperand(Operand):
    def isReg(self):
        return 1

    def isCCReg(self):
        return 1

    def makeConstructor(self, predRead, predWrite):
        c_src = ''
        c_dest = ''

        if self.is_src:
            c_src = '\n\t_srcRegIdx[_numSrcRegs++] = %s + CC_Reg_Base;' % \
                     (self.reg_spec)
            if self.hasReadPred():
                c_src = '\n\tif (%s) {%s\n\t}' % \
                        (self.read_predicate, c_src)

        if self.is_dest:
            c_dest = \
              '\n\t_destRegIdx[_numDestRegs++] = %s + CC_Reg_Base;' % \
              (self.reg_spec)
            c_dest += '\n\t_numCCDestRegs++;'
            if self.hasWritePred():
                c_dest = '\n\tif (%s) {%s\n\t}' % \
                         (self.write_predicate, c_dest)

        return c_src + c_dest

    def makeRead(self, predRead):
        if (self.ctype == 'float' or self.ctype == 'double'):
            error('Attempt to read condition-code register as FP')
        if self.read_code != None:
            return self.buildReadCode('readCCRegOperand')

        int_reg_val = ''
        if predRead:
            int_reg_val = 'xc->readCCRegOperand(this, _sourceIndex++)'
            if self.hasReadPred():
                int_reg_val = '(%s) ? %s : 0' % \
                              (self.read_predicate, int_reg_val)
        else:
            int_reg_val = 'xc->readCCRegOperand(this, %d)' % self.src_reg_idx

        return '%s = %s;\n' % (self.base_name, int_reg_val)

    def makeWrite(self, predWrite):
        if (self.ctype == 'float' or self.ctype == 'double'):
            error('Attempt to write condition-code register as FP')
        if self.write_code != None:
            return self.buildWriteCode('setCCRegOperand')

        if predWrite:
            wp = 'true'
            if self.hasWritePred():
                wp = self.write_predicate

            wcond = 'if (%s)' % (wp)
            windex = '_destIndex++'
        else:
            wcond = ''
            windex = '%d' % self.dest_reg_idx

        wb = '''
        %s
        {
            %s final_val = %s;
            xc->setCCRegOperand(this, %s, final_val);\n
            if (traceData) { traceData->setData(final_val); }
        }''' % (wcond, self.ctype, self.base_name, windex)

        return wb

class ControlRegOperand(Operand):
    def isReg(self):
        return 1

    def isControlReg(self):
        return 1

    def makeConstructor(self, predRead, predWrite):
        c_src = ''
        c_dest = ''

        if self.is_src:
            c_src = \
              '\n\t_srcRegIdx[_numSrcRegs++] = %s + Misc_Reg_Base;' % \
              (self.reg_spec)

        if self.is_dest:
            c_dest = \
              '\n\t_destRegIdx[_numDestRegs++] = %s + Misc_Reg_Base;' % \
              (self.reg_spec)

        return c_src + c_dest

    def makeRead(self, predRead):
        bit_select = 0
        if (self.ctype == 'float' or self.ctype == 'double'):
            error('Attempt to read control register as FP')
        if self.read_code != None:
            return self.buildReadCode('readMiscRegOperand')

        if predRead:
            rindex = '_sourceIndex++'
        else:
            rindex = '%d' % self.src_reg_idx

        return '%s = xc->readMiscRegOperand(this, %s);\n' % \
            (self.base_name, rindex)

    def makeWrite(self, predWrite):
        if (self.ctype == 'float' or self.ctype == 'double'):
            error('Attempt to write control register as FP')
        if self.write_code != None:
            return self.buildWriteCode('setMiscRegOperand')

        if predWrite:
            windex = '_destIndex++'
        else:
            windex = '%d' % self.dest_reg_idx

        wb = 'xc->setMiscRegOperand(this, %s, %s);\n' % \
             (windex, self.base_name)
        wb += 'if (traceData) { traceData->setData(%s); }' % \
              self.base_name

        return wb

class MemOperand(Operand):
    def isMem(self):
        return 1

    def makeConstructor(self, predRead, predWrite):
        return ''

    def makeDecl(self):
        # Note that initializations in the declarations are solely
        # to avoid 'uninitialized variable' errors from the compiler.
        # Declare memory data variable.
        return '%s %s = 0;\n' % (self.ctype, self.base_name)

    def makeRead(self, predRead):
        if self.read_code != None:
            return self.buildReadCode()
        return ''

    def makeWrite(self, predWrite):
        if self.write_code != None:
            return self.buildWriteCode()
        return ''

class PCStateOperand(Operand):
    def makeConstructor(self, predRead, predWrite):
        return ''

    def makeRead(self, predRead):
        if self.reg_spec:
            # A component of the PC state.
            return '%s = __parserAutoPCState.%s();\n' % \
                (self.base_name, self.reg_spec)
        else:
            # The whole PC state itself.
            return '%s = xc->pcState();\n' % self.base_name

    def makeWrite(self, predWrite):
        if self.reg_spec:
            # A component of the PC state.
            return '__parserAutoPCState.%s(%s);\n' % \
                (self.reg_spec, self.base_name)
        else:
            # The whole PC state itself.
            return 'xc->pcState(%s);\n' % self.base_name

    def makeDecl(self):
        ctype = 'TheISA::PCState'
        if self.isPCPart():
            ctype = self.ctype
        return "%s %s;\n" % (ctype, self.base_name)

    def isPCState(self):
        return 1

class OperandList(object):
    '''Find all the operands in the given code block.  Returns an operand
    descriptor list (instance of class OperandList).'''
    def __init__(self, parser, code):
        self.items = []
        self.bases = {}
        # delete strings and comments so we don't match on operands inside
        for regEx in (stringRE, commentRE):
            code = regEx.sub('', code)
        # search for operands
        next_pos = 0
        while 1:
            match = parser.operandsRE.search(code, next_pos)
            if not match:
                # no more matches: we're done
                break
            op = match.groups()
            # regexp groups are operand full name, base, and extension
            (op_full, op_base, op_ext) = op
            # if the token following the operand is an assignment, this is
            # a destination (LHS), else it's a source (RHS)
            is_dest = (assignRE.match(code, match.end()) != None)
            is_src = not is_dest
            # see if we've already seen this one
            op_desc = self.find_base(op_base)
            if op_desc:
                if op_desc.ext != op_ext:
                    error('Inconsistent extensions for operand %s' % \
                          op_base)
                op_desc.is_src = op_desc.is_src or is_src
                op_desc.is_dest = op_desc.is_dest or is_dest
            else:
                # new operand: create new descriptor
                op_desc = parser.operandNameMap[op_base](parser,
                    op_full, op_ext, is_src, is_dest)
                self.append(op_desc)
            # start next search after end of current match
            next_pos = match.end()
        self.sort()
        # enumerate source & dest register operands... used in building
        # constructor later
        self.numSrcRegs = 0
        self.numDestRegs = 0
        self.numFPDestRegs = 0
        self.numIntDestRegs = 0
        self.numCCDestRegs = 0
        self.numMiscDestRegs = 0
        self.memOperand = None

        # Flags to keep track if one or more operands are to be read/written
        # conditionally.
        self.predRead = False
        self.predWrite = False

        for op_desc in self.items:
            if op_desc.isReg():
                if op_desc.is_src:
                    op_desc.src_reg_idx = self.numSrcRegs
                    self.numSrcRegs += 1
                if op_desc.is_dest:
                    op_desc.dest_reg_idx = self.numDestRegs
                    self.numDestRegs += 1
                    if op_desc.isFloatReg():
                        self.numFPDestRegs += 1
                    elif op_desc.isIntReg():
                        self.numIntDestRegs += 1
                    elif op_desc.isCCReg():
                        self.numCCDestRegs += 1
                    elif op_desc.isControlReg():
                        self.numMiscDestRegs += 1
            elif op_desc.isMem():
                if self.memOperand:
                    error("Code block has more than one memory operand.")
                self.memOperand = op_desc

            # Check if this operand has read/write predication. If true, then
            # the microop will dynamically index source/dest registers.
            self.predRead = self.predRead or op_desc.hasReadPred()
            self.predWrite = self.predWrite or op_desc.hasWritePred()

        if parser.maxInstSrcRegs < self.numSrcRegs:
            parser.maxInstSrcRegs = self.numSrcRegs
        if parser.maxInstDestRegs < self.numDestRegs:
            parser.maxInstDestRegs = self.numDestRegs
        if parser.maxMiscDestRegs < self.numMiscDestRegs:
            parser.maxMiscDestRegs = self.numMiscDestRegs

        # now make a final pass to finalize op_desc fields that may depend
        # on the register enumeration
        for op_desc in self.items:
            op_desc.finalize(self.predRead, self.predWrite)

    def __len__(self):
        return len(self.items)

    def __getitem__(self, index):
        return self.items[index]

    def append(self, op_desc):
        self.items.append(op_desc)
        self.bases[op_desc.base_name] = op_desc

    def find_base(self, base_name):
        # like self.bases[base_name], but returns None if not found
        # (rather than raising exception)
        return self.bases.get(base_name)

    # internal helper function for concat[Some]Attr{Strings|Lists}
    def __internalConcatAttrs(self, attr_name, filter, result):
        for op_desc in self.items:
            if filter(op_desc):
                result += getattr(op_desc, attr_name)
        return result

    # return a single string that is the concatenation of the (string)
    # values of the specified attribute for all operands
    def concatAttrStrings(self, attr_name):
        return self.__internalConcatAttrs(attr_name, lambda x: 1, '')

    # like concatAttrStrings, but only include the values for the operands
    # for which the provided filter function returns true
    def concatSomeAttrStrings(self, filter, attr_name):
        return self.__internalConcatAttrs(attr_name, filter, '')

    # return a single list that is the concatenation of the (list)
    # values of the specified attribute for all operands
    def concatAttrLists(self, attr_name):
        return self.__internalConcatAttrs(attr_name, lambda x: 1, [])

    # like concatAttrLists, but only include the values for the operands
    # for which the provided filter function returns true
    def concatSomeAttrLists(self, filter, attr_name):
        return self.__internalConcatAttrs(attr_name, filter, [])

    def sort(self):
        self.items.sort(lambda a, b: a.sort_pri - b.sort_pri)

class SubOperandList(OperandList):
    '''Find all the operands in the given code block.  Returns an operand
    descriptor list (instance of class OperandList).'''
    def __init__(self, parser, code, master_list):
        self.items = []
        self.bases = {}
        # delete strings and comments so we don't match on operands inside
        for regEx in (stringRE, commentRE):
            code = regEx.sub('', code)
        # search for operands
        next_pos = 0
        while 1:
            match = parser.operandsRE.search(code, next_pos)
            if not match:
                # no more matches: we're done
                break
            op = match.groups()
            # regexp groups are operand full name, base, and extension
            (op_full, op_base, op_ext) = op
            # find this op in the master list
            op_desc = master_list.find_base(op_base)
            if not op_desc:
                error('Found operand %s which is not in the master list!' \
                      ' This is an internal error' % op_base)
            else:
                # See if we've already found this operand
                op_desc = self.find_base(op_base)
                if not op_desc:
                    # if not, add a reference to it to this sub list
                    self.append(master_list.bases[op_base])

            # start next search after end of current match
            next_pos = match.end()
        self.sort()
        self.memOperand = None
        # Whether the whole PC needs to be read so parts of it can be accessed
        self.readPC = False
        # Whether the whole PC needs to be written after parts of it were
        # changed
        self.setPC = False
        # Whether this instruction manipulates the whole PC or parts of it.
        # Mixing the two is a bad idea and flagged as an error.
        self.pcPart = None

        # Flags to keep track if one or more operands are to be read/written
        # conditionally.
        self.predRead = False
        self.predWrite = False

        for op_desc in self.items:
            if op_desc.isPCPart():
                self.readPC = True
                if op_desc.is_dest:
                    self.setPC = True

            if op_desc.isPCState():
                if self.pcPart is not None:
                    if self.pcPart and not op_desc.isPCPart() or \
                            not self.pcPart and op_desc.isPCPart():
                        error("Mixed whole and partial PC state operands.")
                self.pcPart = op_desc.isPCPart()

            if op_desc.isMem():
                if self.memOperand:
                    error("Code block has more than one memory operand.")
                self.memOperand = op_desc

            # Check if this operand has read/write predication. If true, then
            # the microop will dynamically index source/dest registers.
            self.predRead = self.predRead or op_desc.hasReadPred()
            self.predWrite = self.predWrite or op_desc.hasWritePred()

# Regular expression object to match C++ strings
stringRE = re.compile(r'"([^"\\]|\\.)*"')

# Regular expression object to match C++ comments
# (used in findOperands())
commentRE = re.compile(r'(^)?[^\S\n]*/(?:\*(.*?)\*/[^\S\n]*|/[^\n]*)($)?',
        re.DOTALL | re.MULTILINE)

# Regular expression object to match assignment statements
# (used in findOperands())
assignRE = re.compile(r'\s*=(?!=)', re.MULTILINE)

def makeFlagConstructor(flag_list):
    if len(flag_list) == 0:
        return ''
    # filter out repeated flags
    flag_list.sort()
    i = 1
    while i < len(flag_list):
        if flag_list[i] == flag_list[i-1]:
            del flag_list[i]
        else:
            i += 1
    pre = '\n\tflags['
    post = '] = true;'
    code = pre + string.join(flag_list, post + pre) + post
    return code

# Assume all instruction flags are of the form 'IsFoo'
instFlagRE = re.compile(r'Is.*')

# OpClass constants end in 'Op' except No_OpClass
opClassRE = re.compile(r'.*Op|No_OpClass')

class InstObjParams(object):
    def __init__(self, parser, mnem, class_name, base_class = '',
                 snippets = {}, opt_args = []):
        self.mnemonic = mnem
        self.class_name = class_name
        self.base_class = base_class
        if not isinstance(snippets, dict):
            snippets = {'code' : snippets}
        compositeCode = ' '.join(map(str, snippets.values()))
        self.snippets = snippets

        self.operands = OperandList(parser, compositeCode)

        # The header of the constructor declares the variables to be used
        # in the body of the constructor.
        header = ''
        header += '\n\t_numSrcRegs = 0;'
        header += '\n\t_numDestRegs = 0;'
        header += '\n\t_numFPDestRegs = 0;'
        header += '\n\t_numIntDestRegs = 0;'
        header += '\n\t_numCCDestRegs = 0;'

        self.constructor = header + \
                           self.operands.concatAttrStrings('constructor')

        self.flags = self.operands.concatAttrLists('flags')

        # Make a basic guess on the operand class (function unit type).
        # These are good enough for most cases, and can be overridden
        # later otherwise.
        if 'IsStore' in self.flags:
            self.op_class = 'MemWriteOp'
        elif 'IsLoad' in self.flags or 'IsPrefetch' in self.flags:
            self.op_class = 'MemReadOp'
        elif 'IsFloating' in self.flags:
            self.op_class = 'FloatAddOp'
        else:
            self.op_class = 'IntAluOp'

        # Optional arguments are assumed to be either StaticInst flags
        # or an OpClass value.  To avoid having to import a complete
        # list of these values to match against, we do it ad-hoc
        # with regexps.
        for oa in opt_args:
            if instFlagRE.match(oa):
                self.flags.append(oa)
            elif opClassRE.match(oa):
                self.op_class = oa
            else:
                error('InstObjParams: optional arg "%s" not recognized '
                      'as StaticInst::Flag or OpClass.' % oa)

        # add flag initialization to contructor here to include
        # any flags added via opt_args
        self.constructor += makeFlagConstructor(self.flags)

        # if 'IsFloating' is set, add call to the FP enable check
        # function (which should be provided by isa_desc via a declare)
        if 'IsFloating' in self.flags:
            self.fp_enable_check = 'fault = checkFpEnableFault(xc);'
        else:
            self.fp_enable_check = ''

##############
# Stack: a simple stack object.  Used for both formats (formatStack)
# and default cases (defaultStack).  Simply wraps a list to give more
# stack-like syntax and enable initialization with an argument list
# (as opposed to an argument that's a list).

class Stack(list):
    def __init__(self, *items):
        list.__init__(self, items)

    def push(self, item):
        self.append(item);

    def top(self):
        return self[-1]

#######################
#
# ISA Parser
#   parses ISA DSL and emits C++ headers and source
#

class ISAParser(Grammar):
    def __init__(self, output_dir, cpu_models):
        super(ISAParser, self).__init__()
        self.output_dir = output_dir

        self.filename = None # for output file watermarking/scaremongering

        self.cpuModels = cpu_models

        # variable to hold templates
        self.templateMap = {}

        # This dictionary maps format name strings to Format objects.
        self.formatMap = {}

        # Track open files and, if applicable, how many chunks it has been
        # split into so far.
        self.files = {}
        self.splits = {}

        # isa_name / namespace identifier from namespace declaration.
        # before the namespace declaration, None.
        self.isa_name = None
        self.namespace = None

        # The format stack.
        self.formatStack = Stack(NoFormat())

        # The default case stack.
        self.defaultStack = Stack(None)

        # Stack that tracks current file and line number.  Each
        # element is a tuple (filename, lineno) that records the
        # *current* filename and the line number in the *previous*
        # file where it was included.
        self.fileNameStack = Stack()

        symbols = ('makeList', 're', 'string')
        self.exportContext = dict([(s, eval(s)) for s in symbols])

        self.maxInstSrcRegs = 0
        self.maxInstDestRegs = 0
        self.maxMiscDestRegs = 0

    def __getitem__(self, i):    # Allow object (self) to be
        return getattr(self, i)  # passed to %-substitutions

    # Change the file suffix of a base filename:
    #   (e.g.) decoder.cc -> decoder-g.cc.inc for 'global' outputs
    def suffixize(self, s, sec):
        extn = re.compile('(\.[^\.]+)$') # isolate extension
        if self.namespace:
            return extn.sub(r'-ns\1.inc', s) # insert some text on either side
        else:
            return extn.sub(r'-g\1.inc', s)

    # Get the file object for emitting code into the specified section
    # (header, decoder, exec, decode_block).
    def get_file(self, section):
        if section == 'decode_block':
            filename = 'decode-method.cc.inc'
        else:
            if section == 'header':
                file = 'decoder.hh'
            else:
                file = '%s.cc' % section
            filename = self.suffixize(file, section)
        try:
            return self.files[filename]
        except KeyError: pass

        f = self.open(filename)
        self.files[filename] = f

        # The splittable files are the ones with many independent
        # per-instruction functions - the decoder's instruction constructors
        # and the instruction execution (execute()) methods. These both have
        # the suffix -ns.cc.inc, meaning they are within the namespace part
        # of the ISA, contain object-emitting C++ source, and are included
        # into other top-level files. These are the files that need special
        # #define's to allow parts of them to be compiled separately. Rather
        # than splitting the emissions into separate files, the monolithic
        # output of the ISA parser is maintained, but the value (or lack
        # thereof) of the __SPLIT definition during C preprocessing will
        # select the different chunks. If no 'split' directives are used,
        # the cpp emissions have no effect.
        if re.search('-ns.cc.inc$', filename):
            print >>f, '#if !defined(__SPLIT) || (__SPLIT == 1)'
            self.splits[f] = 1
        # ensure requisite #include's
        elif filename in ['decoder-g.cc.inc', 'exec-g.cc.inc']:
            print >>f, '#include "decoder.hh"'
        elif filename == 'decoder-g.hh.inc':
            print >>f, '#include "base/bitfield.hh"'

        return f

    # Weave together the parts of the different output sections by
    # #include'ing them into some very short top-level .cc/.hh files.
    # These small files make it much clearer how this tool works, since
    # you directly see the chunks emitted as files that are #include'd.
    def write_top_level_files(self):
        dep = self.open('inc.d', bare=True)

        # decoder header - everything depends on this
        file = 'decoder.hh'
        with self.open(file) as f:
            inc = []

            fn = 'decoder-g.hh.inc'
            assert(fn in self.files)
            f.write('#include "%s"\n' % fn)
            inc.append(fn)

            fn = 'decoder-ns.hh.inc'
            assert(fn in self.files)
            f.write('namespace %s {\n#include "%s"\n}\n'
                    % (self.namespace, fn))
            inc.append(fn)

            print >>dep, file+':', ' '.join(inc)

        # decoder method - cannot be split
        file = 'decoder.cc'
        with self.open(file) as f:
            inc = []

            fn = 'decoder-g.cc.inc'
            assert(fn in self.files)
            f.write('#include "%s"\n' % fn)
            inc.append(fn)

            fn = 'decode-method.cc.inc'
            # is guaranteed to have been written for parse to complete
            f.write('#include "%s"\n' % fn)
            inc.append(fn)

            inc.append("decoder.hh")
            print >>dep, file+':', ' '.join(inc)

        extn = re.compile('(\.[^\.]+)$')

        # instruction constructors
        splits = self.splits[self.get_file('decoder')]
        file_ = 'inst-constrs.cc'
        for i in range(1, splits+1):
            if splits > 1:
                file = extn.sub(r'-%d\1' % i, file_)
            else:
                file = file_
            with self.open(file) as f:
                inc = []

                fn = 'decoder-g.cc.inc'
                assert(fn in self.files)
                f.write('#include "%s"\n' % fn)
                inc.append(fn)

                fn = 'decoder-ns.cc.inc'
                assert(fn in self.files)
                print >>f, 'namespace %s {' % self.namespace
                if splits > 1:
                    print >>f, '#define __SPLIT %u' % i
                print >>f, '#include "%s"' % fn
                print >>f, '}'
                inc.append(fn)

                inc.append("decoder.hh")
                print >>dep, file+':', ' '.join(inc)

        # instruction execution per-CPU model
        splits = self.splits[self.get_file('exec')]
        for cpu in self.cpuModels:
            for i in range(1, splits+1):
                if splits > 1:
                    file = extn.sub(r'_%d\1' % i, cpu.filename)
                else:
                    file = cpu.filename
                with self.open(file) as f:
                    inc = []

                    fn = 'exec-g.cc.inc'
                    assert(fn in self.files)
                    f.write('#include "%s"\n' % fn)
                    inc.append(fn)

                    f.write(cpu.includes+"\n")

                    fn = 'exec-ns.cc.inc'
                    assert(fn in self.files)
                    print >>f, 'namespace %s {' % self.namespace
                    print >>f, '#define CPU_EXEC_CONTEXT %s' \
                               % cpu.strings['CPU_exec_context']
                    if splits > 1:
                        print >>f, '#define __SPLIT %u' % i
                    print >>f, '#include "%s"' % fn
                    print >>f, '}'
                    inc.append(fn)

                    inc.append("decoder.hh")
                    print >>dep, file+':', ' '.join(inc)

        # max_inst_regs.hh
        self.update('max_inst_regs.hh',
                    '''namespace %(namespace)s {
    const int MaxInstSrcRegs = %(maxInstSrcRegs)d;
    const int MaxInstDestRegs = %(maxInstDestRegs)d;
    const int MaxMiscDestRegs = %(maxMiscDestRegs)d;\n}\n''' % self)
        print >>dep, 'max_inst_regs.hh:'

        dep.close()


    scaremonger_template ='''// DO NOT EDIT
// This file was automatically generated from an ISA description:
//   %(filename)s

''';

    #####################################################################
    #
    #                                Lexer
    #
    # The PLY lexer module takes two things as input:
    # - A list of token names (the string list 'tokens')
    # - A regular expression describing a match for each token.  The
    #   regexp for token FOO can be provided in two ways:
    #   - as a string variable named t_FOO
    #   - as the doc string for a function named t_FOO.  In this case,
    #     the function is also executed, allowing an action to be
    #     associated with each token match.
    #
    #####################################################################

    # Reserved words.  These are listed separately as they are matched
    # using the same regexp as generic IDs, but distinguished in the
    # t_ID() function.  The PLY documentation suggests this approach.
    reserved = (
        'BITFIELD', 'DECODE', 'DECODER', 'DEFAULT', 'DEF', 'EXEC', 'FORMAT',
        'HEADER', 'LET', 'NAMESPACE', 'OPERAND_TYPES', 'OPERANDS',
        'OUTPUT', 'SIGNED', 'SPLIT', 'TEMPLATE'
        )

    # List of tokens.  The lex module requires this.
    tokens = reserved + (
        # identifier
        'ID',

        # integer literal
        'INTLIT',

        # string literal
        'STRLIT',

        # code literal
        'CODELIT',

        # ( ) [ ] { } < > , ; . : :: *
        'LPAREN', 'RPAREN',
        'LBRACKET', 'RBRACKET',
        'LBRACE', 'RBRACE',
        'LESS', 'GREATER', 'EQUALS',
        'COMMA', 'SEMI', 'DOT', 'COLON', 'DBLCOLON',
        'ASTERISK',

        # C preprocessor directives
        'CPPDIRECTIVE'

    # The following are matched but never returned. commented out to
    # suppress PLY warning
        # newfile directive
    #    'NEWFILE',

        # endfile directive
    #    'ENDFILE'
    )

    # Regular expressions for token matching
    t_LPAREN           = r'\('
    t_RPAREN           = r'\)'
    t_LBRACKET         = r'\['
    t_RBRACKET         = r'\]'
    t_LBRACE           = r'\{'
    t_RBRACE           = r'\}'
    t_LESS             = r'\<'
    t_GREATER          = r'\>'
    t_EQUALS           = r'='
    t_COMMA            = r','
    t_SEMI             = r';'
    t_DOT              = r'\.'
    t_COLON            = r':'
    t_DBLCOLON         = r'::'
    t_ASTERISK         = r'\*'

    # Identifiers and reserved words
    reserved_map = { }
    for r in reserved:
        reserved_map[r.lower()] = r

    def t_ID(self, t):
        r'[A-Za-z_]\w*'
        t.type = self.reserved_map.get(t.value, 'ID')
        return t

    # Integer literal
    def t_INTLIT(self, t):
        r'-?(0x[\da-fA-F]+)|\d+'
        try:
            t.value = int(t.value,0)
        except ValueError:
            error(t, 'Integer value "%s" too large' % t.value)
            t.value = 0
        return t

    # String literal.  Note that these use only single quotes, and
    # can span multiple lines.
    def t_STRLIT(self, t):
        r"(?m)'([^'])+'"
        # strip off quotes
        t.value = t.value[1:-1]
        t.lexer.lineno += t.value.count('\n')
        return t


    # "Code literal"... like a string literal, but delimiters are
    # '{{' and '}}' so they get formatted nicely under emacs c-mode
    def t_CODELIT(self, t):
        r"(?m)\{\{([^\}]|}(?!\}))+\}\}"
        # strip off {{ & }}
        t.value = t.value[2:-2]
        t.lexer.lineno += t.value.count('\n')
        return t

    def t_CPPDIRECTIVE(self, t):
        r'^\#[^\#].*\n'
        t.lexer.lineno += t.value.count('\n')
        return t

    def t_NEWFILE(self, t):
        r'^\#\#newfile\s+"[^"]*"'
        self.fileNameStack.push((t.value[11:-1], t.lexer.lineno))
        t.lexer.lineno = 0

    def t_ENDFILE(self, t):
        r'^\#\#endfile'
        (old_filename, t.lexer.lineno) = self.fileNameStack.pop()

    #
    # The functions t_NEWLINE, t_ignore, and t_error are
    # special for the lex module.
    #

    # Newlines
    def t_NEWLINE(self, t):
        r'\n+'
        t.lexer.lineno += t.value.count('\n')

    # Comments
    def t_comment(self, t):
        r'//.*'

    # Completely ignored characters
    t_ignore = ' \t\x0c'

    # Error handler
    def t_error(self, t):
        error(t, "illegal character '%s'" % t.value[0])
        t.skip(1)

    #####################################################################
    #
    #                                Parser
    #
    # Every function whose name starts with 'p_' defines a grammar
    # rule.  The rule is encoded in the function's doc string, while
    # the function body provides the action taken when the rule is
    # matched.  The argument to each function is a list of the values
    # of the rule's symbols: t[0] for the LHS, and t[1..n] for the
    # symbols on the RHS.  For tokens, the value is copied from the
    # t.value attribute provided by the lexer.  For non-terminals, the
    # value is assigned by the producing rule; i.e., the job of the
    # grammar rule function is to set the value for the non-terminal
    # on the LHS (by assigning to t[0]).
    #####################################################################

    # The LHS of the first grammar rule is used as the start symbol
    # (in this case, 'specification').  Note that this rule enforces
    # that there will be exactly one namespace declaration, with 0 or
    # more global defs/decls before and after it.  The defs & decls
    # before the namespace decl will be outside the namespace; those
    # after will be inside.  The decoder function is always inside the
    # namespace.
    def p_specification(self, t):
        'specification : opt_defs_and_outputs top_level_decode_block'

        for f in self.splits.iterkeys():
            f.write('\n#endif\n')

        for f in self.files.itervalues(): # close ALL the files;
            f.close() # not doing so can cause compilation to fail

        self.write_top_level_files()

        t[0] = True

    # 'opt_defs_and_outputs' is a possibly empty sequence of def and/or
    # output statements. Its productions do the hard work of eventually
    # instantiating a GenCode, which are generally emitted (written to disk)
    # as soon as possible, except for the decode_block, which has to be
    # accumulated into one large function of nested switch/case blocks.
    def p_opt_defs_and_outputs_0(self, t):
        'opt_defs_and_outputs : empty'

    def p_opt_defs_and_outputs_1(self, t):
        'opt_defs_and_outputs : defs_and_outputs'

    def p_defs_and_outputs_0(self, t):
        'defs_and_outputs : def_or_output'

    def p_defs_and_outputs_1(self, t):
        'defs_and_outputs : defs_and_outputs def_or_output'

    # The list of possible definition/output statements.
    # They are all processed as they are seen.
    def p_def_or_output(self, t):
        '''def_or_output : name_decl
                         | def_format
                         | def_bitfield
                         | def_bitfield_struct
                         | def_template
                         | def_operand_types
                         | def_operands
                         | output
                         | global_let
                         | split'''

    # Utility function used by both invocations of splitting - explicit
    # 'split' keyword and split() function inside "let {{ }};" blocks.
    def split(self, sec, write=False):
        assert(sec != 'header' and "header cannot be split")

        f = self.get_file(sec)
        self.splits[f] += 1
        s = '\n#endif\n#if __SPLIT == %u\n' % self.splits[f]
        if write:
            f.write(s)
        else:
            return s

    # split output file to reduce compilation time
    def p_split(self, t):
        'split : SPLIT output_type SEMI'
        assert(self.isa_name and "'split' not allowed before namespace decl")

        self.split(t[2], True)

    def p_output_type(self, t):
        '''output_type : DECODER
                       | HEADER
                       | EXEC'''
        t[0] = t[1]

    # ISA name declaration looks like "namespace <foo>;"
    def p_name_decl(self, t):
        'name_decl : NAMESPACE ID SEMI'
        assert(self.isa_name == None and "Only 1 namespace decl permitted")
        self.isa_name = t[2]
        self.namespace = t[2] + 'Inst'

    # Output blocks 'output <foo> {{...}}' (C++ code blocks) are copied
    # directly to the appropriate output section.

    # Massage output block by substituting in template definitions and
    # bit operators.  We handle '%'s embedded in the string that don't
    # indicate template substitutions (or CPU-specific symbols, which
    # get handled in GenCode) by doubling them first so that the
    # format operation will reduce them back to single '%'s.
    def process_output(self, s):
        s = self.protectNonSubstPercents(s)
        # protects cpu-specific symbols too
        s = self.protectCpuSymbols(s)
        return substBitOps(s % self.templateMap)

    def p_output(self, t):
        'output : OUTPUT output_type CODELIT SEMI'
        kwargs = { t[2]+'_output' : self.process_output(t[3]) }
        GenCode(self, **kwargs).emit()

    # global let blocks 'let {{...}}' (Python code blocks) are
    # executed directly when seen.  Note that these execute in a
    # special variable context 'exportContext' to prevent the code
    # from polluting this script's namespace.
    def p_global_let(self, t):
        'global_let : LET CODELIT SEMI'
        def _split(sec):
            return self.split(sec)
        self.updateExportContext()
        self.exportContext["header_output"] = ''
        self.exportContext["decoder_output"] = ''
        self.exportContext["exec_output"] = ''
        self.exportContext["decode_block"] = ''
        self.exportContext["split"] = _split
        split_setup = '''
def wrap(func):
    def split(sec):
        globals()[sec + '_output'] += func(sec)
    return split
split = wrap(split)
del wrap
'''
        # This tricky setup (immediately above) allows us to just write
        # (e.g.) "split('exec')" in the Python code and the split #ifdef's
        # will automatically be added to the exec_output variable. The inner
        # Python execution environment doesn't know about the split points,
        # so we carefully inject and wrap a closure that can retrieve the
        # next split's #define from the parser and add it to the current
        # emission-in-progress.
        try:
            exec split_setup+fixPythonIndentation(t[2]) in self.exportContext
        except Exception, exc:
            if debug:
                raise
            error(t, 'error: %s in global let block "%s".' % (exc, t[2]))
        GenCode(self,
                header_output=self.exportContext["header_output"],
                decoder_output=self.exportContext["decoder_output"],
                exec_output=self.exportContext["exec_output"],
                decode_block=self.exportContext["decode_block"]).emit()

    # Define the mapping from operand type extensions to C++ types and
    # bit widths (stored in operandTypeMap).
    def p_def_operand_types(self, t):
        'def_operand_types : DEF OPERAND_TYPES CODELIT SEMI'
        try:
            self.operandTypeMap = eval('{' + t[3] + '}')
        except Exception, exc:
            if debug:
                raise
            error(t,
                  'error: %s in def operand_types block "%s".' % (exc, t[3]))

    # Define the mapping from operand names to operand classes and
    # other traits.  Stored in operandNameMap.
    def p_def_operands(self, t):
        'def_operands : DEF OPERANDS CODELIT SEMI'
        if not hasattr(self, 'operandTypeMap'):
            error(t, 'error: operand types must be defined before operands')
        try:
            user_dict = eval('{' + t[3] + '}', self.exportContext)
        except Exception, exc:
            if debug:
                raise
            error(t, 'error: %s in def operands block "%s".' % (exc, t[3]))
        self.buildOperandNameMap(user_dict, t.lexer.lineno)

    # A bitfield definition looks like:
    # 'def [signed] bitfield <ID> [<first>:<last>]'
    # This generates a preprocessor macro in the output file.
    def p_def_bitfield_0(self, t):
        'def_bitfield : DEF opt_signed BITFIELD ID LESS INTLIT COLON INTLIT GREATER SEMI'
        expr = 'bits(machInst, %2d, %2d)' % (t[6], t[8])
        if (t[2] == 'signed'):
            expr = 'sext<%d>(%s)' % (t[6] - t[8] + 1, expr)
        hash_define = '#undef %s\n#define %s\t%s\n' % (t[4], t[4], expr)
        GenCode(self, header_output=hash_define).emit()

    # alternate form for single bit: 'def [signed] bitfield <ID> [<bit>]'
    def p_def_bitfield_1(self, t):
        'def_bitfield : DEF opt_signed BITFIELD ID LESS INTLIT GREATER SEMI'
        expr = 'bits(machInst, %2d, %2d)' % (t[6], t[6])
        if (t[2] == 'signed'):
            expr = 'sext<%d>(%s)' % (1, expr)
        hash_define = '#undef %s\n#define %s\t%s\n' % (t[4], t[4], expr)
        GenCode(self, header_output=hash_define).emit()

    # alternate form for structure member: 'def bitfield <ID> <ID>'
    def p_def_bitfield_struct(self, t):
        'def_bitfield_struct : DEF opt_signed BITFIELD ID id_with_dot SEMI'
        if (t[2] != ''):
            error(t, 'error: structure bitfields are always unsigned.')
        expr = 'machInst.%s' % t[5]
        hash_define = '#undef %s\n#define %s\t%s\n' % (t[4], t[4], expr)
        GenCode(self, header_output=hash_define).emit()

    def p_id_with_dot_0(self, t):
        'id_with_dot : ID'
        t[0] = t[1]

    def p_id_with_dot_1(self, t):
        'id_with_dot : ID DOT id_with_dot'
        t[0] = t[1] + t[2] + t[3]

    def p_opt_signed_0(self, t):
        'opt_signed : SIGNED'
        t[0] = t[1]

    def p_opt_signed_1(self, t):
        'opt_signed : empty'
        t[0] = ''

    def p_def_template(self, t):
        'def_template : DEF TEMPLATE ID CODELIT SEMI'
        if t[3] in self.templateMap:
            print "warning: template %s already defined" % t[3]
        self.templateMap[t[3]] = Template(self, t[4])

    # An instruction format definition looks like
    # "def format <fmt>(<params>) {{...}};"
    def p_def_format(self, t):
        'def_format : DEF FORMAT ID LPAREN param_list RPAREN CODELIT SEMI'
        (id, params, code) = (t[3], t[5], t[7])
        self.defFormat(id, params, code, t.lexer.lineno)

    # The formal parameter list for an instruction format is a
    # possibly empty list of comma-separated parameters.  Positional
    # (standard, non-keyword) parameters must come first, followed by
    # keyword parameters, followed by a '*foo' parameter that gets
    # excess positional arguments (as in Python).  Each of these three
    # parameter categories is optional.
    #
    # Note that we do not support the '**foo' parameter for collecting
    # otherwise undefined keyword args.  Otherwise the parameter list
    # is (I believe) identical to what is supported in Python.
    #
    # The param list generates a tuple, where the first element is a
    # list of the positional params and the second element is a dict
    # containing the keyword params.
    def p_param_list_0(self, t):
        'param_list : positional_param_list COMMA nonpositional_param_list'
        t[0] = t[1] + t[3]

    def p_param_list_1(self, t):
        '''param_list : positional_param_list
                      | nonpositional_param_list'''
        t[0] = t[1]

    def p_positional_param_list_0(self, t):
        'positional_param_list : empty'
        t[0] = []

    def p_positional_param_list_1(self, t):
        'positional_param_list : ID'
        t[0] = [t[1]]

    def p_positional_param_list_2(self, t):
        'positional_param_list : positional_param_list COMMA ID'
        t[0] = t[1] + [t[3]]

    def p_nonpositional_param_list_0(self, t):
        'nonpositional_param_list : keyword_param_list COMMA excess_args_param'
        t[0] = t[1] + t[3]

    def p_nonpositional_param_list_1(self, t):
        '''nonpositional_param_list : keyword_param_list
                                    | excess_args_param'''
        t[0] = t[1]

    def p_keyword_param_list_0(self, t):
        'keyword_param_list : keyword_param'
        t[0] = [t[1]]

    def p_keyword_param_list_1(self, t):
        'keyword_param_list : keyword_param_list COMMA keyword_param'
        t[0] = t[1] + [t[3]]

    def p_keyword_param(self, t):
        'keyword_param : ID EQUALS expr'
        t[0] = t[1] + ' = ' + t[3].__repr__()

    def p_excess_args_param(self, t):
        'excess_args_param : ASTERISK ID'
        # Just concatenate them: '*ID'.  Wrap in list to be consistent
        # with positional_param_list and keyword_param_list.
        t[0] = [t[1] + t[2]]

    # End of format definition-related rules.
    ##############

    #
    # A decode block looks like:
    #       decode <field1> [, <field2>]* [default <inst>] { ... }
    #
    def p_top_level_decode_block(self, t):
        'top_level_decode_block : decode_block'
        codeObj = t[1]
        codeObj.wrap_decode_block('''
StaticInstPtr
%(isa_name)s::Decoder::decodeInst(%(isa_name)s::ExtMachInst machInst)
{
    using namespace %(namespace)s;
''' % self, '}')

        codeObj.emit()

    def p_decode_block(self, t):
        'decode_block : DECODE ID opt_default LBRACE decode_stmt_list RBRACE'
        default_defaults = self.defaultStack.pop()
        codeObj = t[5]
        # use the "default defaults" only if there was no explicit
        # default statement in decode_stmt_list
        if not codeObj.has_decode_default:
            codeObj += default_defaults
        codeObj.wrap_decode_block('switch (%s) {\n' % t[2], '}\n')
        t[0] = codeObj

    # The opt_default statement serves only to push the "default
    # defaults" onto defaultStack.  This value will be used by nested
    # decode blocks, and used and popped off when the current
    # decode_block is processed (in p_decode_block() above).
    def p_opt_default_0(self, t):
        'opt_default : empty'
        # no default specified: reuse the one currently at the top of
        # the stack
        self.defaultStack.push(self.defaultStack.top())
        # no meaningful value returned
        t[0] = None

    def p_opt_default_1(self, t):
        'opt_default : DEFAULT inst'
        # push the new default
        codeObj = t[2]
        codeObj.wrap_decode_block('\ndefault:\n', 'break;\n')
        self.defaultStack.push(codeObj)
        # no meaningful value returned
        t[0] = None

    def p_decode_stmt_list_0(self, t):
        'decode_stmt_list : decode_stmt'
        t[0] = t[1]

    def p_decode_stmt_list_1(self, t):
        'decode_stmt_list : decode_stmt decode_stmt_list'
        if (t[1].has_decode_default and t[2].has_decode_default):
            error(t, 'Two default cases in decode block')
        t[0] = t[1] + t[2]

    #
    # Decode statement rules
    #
    # There are four types of statements allowed in a decode block:
    # 1. Format blocks 'format <foo> { ... }'
    # 2. Nested decode blocks
    # 3. Instruction definitions.
    # 4. C preprocessor directives.


    # Preprocessor directives found in a decode statement list are
    # passed through to the output, replicated to all of the output
    # code streams.  This works well for ifdefs, so we can ifdef out
    # both the declarations and the decode cases generated by an
    # instruction definition.  Handling them as part of the grammar
    # makes it easy to keep them in the right place with respect to
    # the code generated by the other statements.
    def p_decode_stmt_cpp(self, t):
        'decode_stmt : CPPDIRECTIVE'
        t[0] = GenCode(self, t[1], t[1], t[1], t[1])

    # A format block 'format <foo> { ... }' sets the default
    # instruction format used to handle instruction definitions inside
    # the block.  This format can be overridden by using an explicit
    # format on the instruction definition or with a nested format
    # block.
    def p_decode_stmt_format(self, t):
        'decode_stmt : FORMAT push_format_id LBRACE decode_stmt_list RBRACE'
        # The format will be pushed on the stack when 'push_format_id'
        # is processed (see below).  Once the parser has recognized
        # the full production (though the right brace), we're done
        # with the format, so now we can pop it.
        self.formatStack.pop()
        t[0] = t[4]

    # This rule exists so we can set the current format (& push the
    # stack) when we recognize the format name part of the format
    # block.
    def p_push_format_id(self, t):
        'push_format_id : ID'
        try:
            self.formatStack.push(self.formatMap[t[1]])
            t[0] = ('', '// format %s' % t[1])
        except KeyError:
            error(t, 'instruction format "%s" not defined.' % t[1])

    # Nested decode block: if the value of the current field matches
    # the specified constant, do a nested decode on some other field.
    def p_decode_stmt_decode(self, t):
        'decode_stmt : case_label COLON decode_block'
        label = t[1]
        codeObj = t[3]
        # just wrap the decoding code from the block as a case in the
        # outer switch statement.
        codeObj.wrap_decode_block('\n%s:\n' % label)
        codeObj.has_decode_default = (label == 'default')
        t[0] = codeObj

    # Instruction definition (finally!).
    def p_decode_stmt_inst(self, t):
        'decode_stmt : case_label COLON inst SEMI'
        label = t[1]
        codeObj = t[3]
        codeObj.wrap_decode_block('\n%s:' % label, 'break;\n')
        codeObj.has_decode_default = (label == 'default')
        t[0] = codeObj

    # The case label is either a list of one or more constants or
    # 'default'
    def p_case_label_0(self, t):
        'case_label : intlit_list'
        def make_case(intlit):
            if intlit >= 2**32:
                return 'case ULL(%#x)' % intlit
            else:
                return 'case %#x' % intlit
        t[0] = ': '.join(map(make_case, t[1]))

    def p_case_label_1(self, t):
        'case_label : DEFAULT'
        t[0] = 'default'

    #
    # The constant list for a decode case label must be non-empty, but
    # may have one or more comma-separated integer literals in it.
    #
    def p_intlit_list_0(self, t):
        'intlit_list : INTLIT'
        t[0] = [t[1]]

    def p_intlit_list_1(self, t):
        'intlit_list : intlit_list COMMA INTLIT'
        t[0] = t[1]
        t[0].append(t[3])

    # Define an instruction using the current instruction format
    # (specified by an enclosing format block).
    # "<mnemonic>(<args>)"
    def p_inst_0(self, t):
        'inst : ID LPAREN arg_list RPAREN'
        # Pass the ID and arg list to the current format class to deal with.
        currentFormat = self.formatStack.top()
        codeObj = currentFormat.defineInst(self, t[1], t[3], t.lexer.lineno)
        args = ','.join(map(str, t[3]))
        args = re.sub('(?m)^', '//', args)
        args = re.sub('^//', '', args)
        comment = '\n// %s::%s(%s)\n' % (currentFormat.id, t[1], args)
        codeObj.prepend_all(comment)
        t[0] = codeObj

    # Define an instruction using an explicitly specified format:
    # "<fmt>::<mnemonic>(<args>)"
    def p_inst_1(self, t):
        'inst : ID DBLCOLON ID LPAREN arg_list RPAREN'
        try:
            format = self.formatMap[t[1]]
        except KeyError:
            error(t, 'instruction format "%s" not defined.' % t[1])

        codeObj = format.defineInst(self, t[3], t[5], t.lexer.lineno)
        comment = '\n// %s::%s(%s)\n' % (t[1], t[3], t[5])
        codeObj.prepend_all(comment)
        t[0] = codeObj

    # The arg list generates a tuple, where the first element is a
    # list of the positional args and the second element is a dict
    # containing the keyword args.
    def p_arg_list_0(self, t):
        'arg_list : positional_arg_list COMMA keyword_arg_list'
        t[0] = ( t[1], t[3] )

    def p_arg_list_1(self, t):
        'arg_list : positional_arg_list'
        t[0] = ( t[1], {} )

    def p_arg_list_2(self, t):
        'arg_list : keyword_arg_list'
        t[0] = ( [], t[1] )

    def p_positional_arg_list_0(self, t):
        'positional_arg_list : empty'
        t[0] = []

    def p_positional_arg_list_1(self, t):
        'positional_arg_list : expr'
        t[0] = [t[1]]

    def p_positional_arg_list_2(self, t):
        'positional_arg_list : positional_arg_list COMMA expr'
        t[0] = t[1] + [t[3]]

    def p_keyword_arg_list_0(self, t):
        'keyword_arg_list : keyword_arg'
        t[0] = t[1]

    def p_keyword_arg_list_1(self, t):
        'keyword_arg_list : keyword_arg_list COMMA keyword_arg'
        t[0] = t[1]
        t[0].update(t[3])

    def p_keyword_arg(self, t):
        'keyword_arg : ID EQUALS expr'
        t[0] = { t[1] : t[3] }

    #
    # Basic expressions.  These constitute the argument values of
    # "function calls" (i.e. instruction definitions in the decode
    # block) and default values for formal parameters of format
    # functions.
    #
    # Right now, these are either strings, integers, or (recursively)
    # lists of exprs (using Python square-bracket list syntax).  Note
    # that bare identifiers are trated as string constants here (since
    # there isn't really a variable namespace to refer to).
    #
    def p_expr_0(self, t):
        '''expr : ID
                | INTLIT
                | STRLIT
                | CODELIT'''
        t[0] = t[1]

    def p_expr_1(self, t):
        '''expr : LBRACKET list_expr RBRACKET'''
        t[0] = t[2]

    def p_list_expr_0(self, t):
        'list_expr : expr'
        t[0] = [t[1]]

    def p_list_expr_1(self, t):
        'list_expr : list_expr COMMA expr'
        t[0] = t[1] + [t[3]]

    def p_list_expr_2(self, t):
        'list_expr : empty'
        t[0] = []

    #
    # Empty production... use in other rules for readability.
    #
    def p_empty(self, t):
        'empty :'
        pass

    # Parse error handler.  Note that the argument here is the
    # offending *token*, not a grammar symbol (hence the need to use
    # t.value)
    def p_error(self, t):
        if t:
            error(t, "syntax error at '%s'" % t.value)
        else:
            error("unknown syntax error")

    # END OF GRAMMAR RULES

    def updateExportContext(self):

        # create a continuation that allows us to grab the current parser
        def wrapInstObjParams(*args):
            return InstObjParams(self, *args)
        self.exportContext['InstObjParams'] = wrapInstObjParams
        self.exportContext.update(self.templateMap)

    def defFormat(self, id, params, code, lineno):
        '''Define a new format'''

        # make sure we haven't already defined this one
        if id in self.formatMap:
            error(lineno, 'format %s redefined.' % id)

        # create new object and store in global map
        self.formatMap[id] = Format(id, params, code)

    def expandCpuSymbolsToDict(self, template):
        '''Expand template with CPU-specific references into a
        dictionary with an entry for each CPU model name.  The entry
        key is the model name and the corresponding value is the
        template with the CPU-specific refs substituted for that
        model.'''

        # Protect '%'s that don't go with CPU-specific terms
        t = re.sub(r'%(?!\(CPU_)', '%%', template)
        result = {}
        for cpu in self.cpuModels:
            result[cpu.name] = t % cpu.strings
        return result

    def expandCpuSymbolsToString(self, template):
        '''*If* the template has CPU-specific references, return a
        single string containing a copy of the template for each CPU
        model with the corresponding values substituted in.  If the
        template has no CPU-specific references, it is returned
        unmodified.'''

        if template.find('%(CPU_') != -1:
            return reduce(lambda x,y: x+y,
                          self.expandCpuSymbolsToDict(template).values())
        else:
            return template

    def protectCpuSymbols(self, template):
        '''Protect CPU-specific references by doubling the
        corresponding '%'s (in preparation for substituting a different
        set of references into the template).'''

        return re.sub(r'%(?=\(CPU_)', '%%', template)

    def protectNonSubstPercents(self, s):
        '''Protect any non-dict-substitution '%'s in a format string
        (i.e. those not followed by '(')'''

        return re.sub(r'%(?!\()', '%%', s)

    def buildOperandNameMap(self, user_dict, lineno):
        operand_name = {}
        for op_name, val in user_dict.iteritems():

            # Check if extra attributes have been specified.
            if len(val) > 9:
                error(lineno, 'error: too many attributes for operand "%s"' %
                      base_cls_name)

            # Pad val with None in case optional args are missing
            val += (None, None, None, None)
            base_cls_name, dflt_ext, reg_spec, flags, sort_pri, \
            read_code, write_code, read_predicate, write_predicate = val[:9]

            # Canonical flag structure is a triple of lists, where each list
            # indicates the set of flags implied by this operand always, when
            # used as a source, and when used as a dest, respectively.
            # For simplicity this can be initialized using a variety of fairly
            # obvious shortcuts; we convert these to canonical form here.
            if not flags:
                # no flags specified (e.g., 'None')
                flags = ( [], [], [] )
            elif isinstance(flags, str):
                # a single flag: assumed to be unconditional
                flags = ( [ flags ], [], [] )
            elif isinstance(flags, list):
                # a list of flags: also assumed to be unconditional
                flags = ( flags, [], [] )
            elif isinstance(flags, tuple):
                # it's a tuple: it should be a triple,
                # but each item could be a single string or a list
                (uncond_flags, src_flags, dest_flags) = flags
                flags = (makeList(uncond_flags),
                         makeList(src_flags), makeList(dest_flags))

            # Accumulate attributes of new operand class in tmp_dict
            tmp_dict = {}
            attrList = ['reg_spec', 'flags', 'sort_pri',
                        'read_code', 'write_code',
                        'read_predicate', 'write_predicate']
            if dflt_ext:
                dflt_ctype = self.operandTypeMap[dflt_ext]
                attrList.extend(['dflt_ctype', 'dflt_ext'])
            for attr in attrList:
                tmp_dict[attr] = eval(attr)
            tmp_dict['base_name'] = op_name

            # New class name will be e.g. "IntReg_Ra"
            cls_name = base_cls_name + '_' + op_name
            # Evaluate string arg to get class object.  Note that the
            # actual base class for "IntReg" is "IntRegOperand", i.e. we
            # have to append "Operand".
            try:
                base_cls = eval(base_cls_name + 'Operand')
            except NameError:
                error(lineno,
                      'error: unknown operand base class "%s"' % base_cls_name)
            # The following statement creates a new class called
            # <cls_name> as a subclass of <base_cls> with the attributes
            # in tmp_dict, just as if we evaluated a class declaration.
            operand_name[op_name] = type(cls_name, (base_cls,), tmp_dict)

        self.operandNameMap = operand_name

        # Define operand variables.
        operands = user_dict.keys()
        extensions = self.operandTypeMap.keys()

        operandsREString = r'''
        (?<!\w)      # neg. lookbehind assertion: prevent partial matches
        ((%s)(?:_(%s))?)   # match: operand with optional '_' then suffix
        (?!\w)       # neg. lookahead assertion: prevent partial matches
        ''' % (string.join(operands, '|'), string.join(extensions, '|'))

        self.operandsRE = re.compile(operandsREString, re.MULTILINE|re.VERBOSE)

        # Same as operandsREString, but extension is mandatory, and only two
        # groups are returned (base and ext, not full name as above).
        # Used for subtituting '_' for '.' to make C++ identifiers.
        operandsWithExtREString = r'(?<!\w)(%s)_(%s)(?!\w)' \
            % (string.join(operands, '|'), string.join(extensions, '|'))

        self.operandsWithExtRE = \
            re.compile(operandsWithExtREString, re.MULTILINE)

    def substMungedOpNames(self, code):
        '''Munge operand names in code string to make legal C++
        variable names.  This means getting rid of the type extension
        if any.  Will match base_name attribute of Operand object.)'''
        return self.operandsWithExtRE.sub(r'\1', code)

    def mungeSnippet(self, s):
        '''Fix up code snippets for final substitution in templates.'''
        if isinstance(s, str):
            return self.substMungedOpNames(substBitOps(s))
        else:
            return s

    def open(self, name, bare=False):
        '''Open the output file for writing and include scary warning.'''
        filename = os.path.join(self.output_dir, name)
        f = open(filename, 'w')
        if f:
            if not bare:
                f.write(ISAParser.scaremonger_template % self)
        return f

    def update(self, file, contents):
        '''Update the output file only.  Scons should handle the case when
        the new contents are unchanged using its built-in hash feature.'''
        f = self.open(file)
        f.write(contents)
        f.close()

    # This regular expression matches '##include' directives
    includeRE = re.compile(r'^\s*##include\s+"(?P<filename>[^"]*)".*$',
                           re.MULTILINE)

    def replace_include(self, matchobj, dirname):
        """Function to replace a matched '##include' directive with the
        contents of the specified file (with nested ##includes
        replaced recursively).  'matchobj' is an re match object
        (from a match of includeRE) and 'dirname' is the directory
        relative to which the file path should be resolved."""

        fname = matchobj.group('filename')
        full_fname = os.path.normpath(os.path.join(dirname, fname))
        contents = '##newfile "%s"\n%s\n##endfile\n' % \
                   (full_fname, self.read_and_flatten(full_fname))
        return contents

    def read_and_flatten(self, filename):
        """Read a file and recursively flatten nested '##include' files."""

        current_dir = os.path.dirname(filename)
        try:
            contents = open(filename).read()
        except IOError:
            error('Error including file "%s"' % filename)

        self.fileNameStack.push((filename, 0))

        # Find any includes and include them
        def replace(matchobj):
            return self.replace_include(matchobj, current_dir)
        contents = self.includeRE.sub(replace, contents)

        self.fileNameStack.pop()
        return contents

    AlreadyGenerated = {}

    def _parse_isa_desc(self, isa_desc_file):
        '''Read in and parse the ISA description.'''

        # The build system can end up running the ISA parser twice: once to
        # finalize the build dependencies, and then to actually generate
        # the files it expects (in src/arch/$ARCH/generated). This code
        # doesn't do anything different either time, however; the SCons
        # invocations just expect different things. Since this code runs
        # within SCons, we can just remember that we've already run and
        # not perform a completely unnecessary run, since the ISA parser's
        # effect is idempotent.
        if isa_desc_file in ISAParser.AlreadyGenerated:
            return

        # grab the last three path components of isa_desc_file
        self.filename = '/'.join(isa_desc_file.split('/')[-3:])

        # Read file and (recursively) all included files into a string.
        # PLY requires that the input be in a single string so we have to
        # do this up front.
        isa_desc = self.read_and_flatten(isa_desc_file)

        # Initialize filename stack with outer file.
        self.fileNameStack.push((isa_desc_file, 0))

        # Parse.
        self.parse_string(isa_desc)

        ISAParser.AlreadyGenerated[isa_desc_file] = None

    def parse_isa_desc(self, *args, **kwargs):
        try:
            self._parse_isa_desc(*args, **kwargs)
        except ISAParserError, e:
            e.exit(self.fileNameStack)

# Called as script: get args from command line.
# Args are: <path to cpu_models.py> <isa desc file> <output dir> <cpu models>
if __name__ == '__main__':
    execfile(sys.argv[1])  # read in CpuModel definitions
    cpu_models = [CpuModel.dict[cpu] for cpu in sys.argv[4:]]
    ISAParser(sys.argv[3], cpu_models).parse_isa_desc(sys.argv[2])

# Copyright (c) 2003-2005 The Regents of The University of Michigan
# Copyright (c) 2013 Advanced Micro Devices, Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met: redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer;
# redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution;
# neither the name of the copyright holders nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# Authors: <NAME>

from __future__ import with_statement
import os
import sys
import re
import string
import inspect, traceback
# get type names
from types import *

from m5.util.grammar import Grammar

debug=False

###################
# Utility functions

#
# Indent every line in string 's' by two spaces
# (except preprocessor directives).
# Used to make nested code blocks look pretty.
#
def indent(s):
    return re.sub(r'(?m)^(?!#)', '  ', s)

#
# Munge a somewhat arbitrarily formatted piece of Python code
# (e.g. from a format 'let' block) into something whose indentation
# will get by the Python parser.
#
# The two keys here are that Python will give a syntax error if
# there's any whitespace at the beginning of the first line, and that
# all lines at the same lexical nesting level must have identical
# indentation.  Unfortunately the way code literals work, an entire
# let block tends to have some initial indentation.  Rather than
# trying to figure out what that is and strip it off, we prepend 'if
# 1:' to make the let code the nested block inside the if (and have
# the parser automatically deal with the indentation for us).
#
# We don't want to do this if (1) the code block is empty or (2) the
# first line of the block doesn't have any whitespace at the front.

def fixPythonIndentation(s):
    # get rid of blank lines first
    s = re.sub(r'(?m)^\s*\n', '', s);
    if (s != '' and re.match(r'[ \t]', s[0])):
        s = 'if 1:\n' + s
    return s

class ISAParserError(Exception):
    """Error handler for parser errors"""
    def __init__(self, first, second=None):
        if second is None:
            self.lineno = 0
            self.string = first
        else:
            if hasattr(first, 'lexer'):
                first = first.lexer.lineno
            self.lineno = first
            self.string = second

    def display(self, filename_stack, print_traceback=debug):
        # Output formatted to work under Emacs compile-mode.  Optional
        # 'print_traceback' arg, if set to True, prints a Python stack
        # backtrace too (can be handy when trying to debug the parser
        # itself).

        spaces = ""
        for (filename, line) in filename_stack[:-1]:
            print "%sIn file included from %s:" % (spaces, filename)
            spaces += "  "

        # Print a Python stack backtrace if requested.
        if print_traceback or not self.lineno:
            traceback.print_exc()

        line_str = "%s:" % (filename_stack[-1][0], )
        if self.lineno:
            line_str += "%d:" % (self.lineno, )

        return "%s%s %s" % (spaces, line_str, self.string)

    def exit(self, filename_stack, print_traceback=debug):
        # Just call exit.

        sys.exit(self.display(filename_stack, print_traceback))

def error(*args):
    raise ISAParserError(*args)

####################
# Template objects.
#
# Template objects are format strings that allow substitution from
# the attribute spaces of other objects (e.g. InstObjParams instances).

labelRE = re.compile(r'(?<!%)%\(([^\)]+)\)[sd]')

class Template(object):
    def __init__(self, parser, t):
        self.parser = parser
        self.template = t

    def subst(self, d):
        myDict = None

        # Protect non-Python-dict substitutions (e.g. if there's a printf
        # in the templated C++ code)
        template = self.parser.protectNonSubstPercents(self.template)
        # CPU-model-specific substitutions are handled later (in GenCode).
        template = self.parser.protectCpuSymbols(template)

        # Build a dict ('myDict') to use for the template substitution.
        # Start with the template namespace.  Make a copy since we're
        # going to modify it.
        myDict = self.parser.templateMap.copy()

        if isinstance(d, InstObjParams):
            # If we're dealing with an InstObjParams object, we need
            # to be a little more sophisticated.  The instruction-wide
            # parameters are already formed, but the parameters which
            # are only function wide still need to be generated.
            compositeCode = ''

            myDict.update(d.__dict__)
            # The "operands" and "snippets" attributes of the InstObjParams
            # objects are for internal use and not substitution.
            del myDict['operands']
            del myDict['snippets']

            snippetLabels = [l for l in labelRE.findall(template)
                             if d.snippets.has_key(l)]

            snippets = dict([(s, self.parser.mungeSnippet(d.snippets[s]))
                             for s in snippetLabels])

            myDict.update(snippets)

            compositeCode = ' '.join(map(str, snippets.values()))

            # Add in template itself in case it references any
            # operands explicitly (like Mem)
            compositeCode += ' ' + template

            operands = SubOperandList(self.parser, compositeCode, d.operands)

            myDict['op_decl'] = operands.concatAttrStrings('op_decl')
            if operands.readPC or operands.setPC:
                myDict['op_decl'] += 'TheISA::PCState __parserAutoPCState;\n'

            # In case there are predicated register reads and write, declare
            # the variables for register indicies. It is being assumed that
            # all the operands in the OperandList are also in the
            # SubOperandList and in the same order. Otherwise, it is
            # expected that predication would not be used for the operands.
            if operands.predRead:
                myDict['op_decl'] += 'uint8_t _sourceIndex = 0;\n'
            if operands.predWrite:
                myDict['op_decl'] += 'uint8_t M5_VAR_USED _destIndex = 0;\n'

            is_src = lambda op: op.is_src
            is_dest = lambda op: op.is_dest

            myDict['op_src_decl'] = \
                      operands.concatSomeAttrStrings(is_src, 'op_src_decl')
            myDict['op_dest_decl'] = \
                      operands.concatSomeAttrStrings(is_dest, 'op_dest_decl')
            if operands.readPC:
                myDict['op_src_decl'] += \
                    'TheISA::PCState __parserAutoPCState;\n'
            if operands.setPC:
                myDict['op_dest_decl'] += \
                    'TheISA::PCState __parserAutoPCState;\n'

            myDict['op_rd'] = operands.concatAttrStrings('op_rd')
            if operands.readPC:
                myDict['op_rd'] = '__parserAutoPCState = xc->pcState();\n' + \
                                  myDict['op_rd']

            # Compose the op_wb string. If we're going to write back the
            # PC state because we changed some of its elements, we'll need to
            # do that as early as possible. That allows later uncoordinated
            # modifications to the PC to layer appropriately.
            reordered = list(operands.items)
            reordered.reverse()
            op_wb_str = ''
            pcWbStr = 'xc->pcState(__parserAutoPCState);\n'
            for op_desc in reordered:
                if op_desc.isPCPart() and op_desc.is_dest:
                    op_wb_str = op_desc.op_wb + pcWbStr + op_wb_str
                    pcWbStr = ''
                else:
                    op_wb_str = op_desc.op_wb + op_wb_str
            myDict['op_wb'] = op_wb_str

        elif isinstance(d, dict):
            # if the argument is a dictionary, we just use it.
            myDict.update(d)
        elif hasattr(d, '__dict__'):
            # if the argument is an object, we use its attribute map.
            myDict.update(d.__dict__)
        else:
            raise TypeError, "Template.subst() arg must be or have dictionary"
        return template % myDict

    # Convert to string.  This handles the case when a template with a
    # CPU-specific term gets interpolated into another template or into
    # an output block.
    def __str__(self):
        return self.parser.expandCpuSymbolsToString(self.template)

################
# Format object.
#
# A format object encapsulates an instruction format.  It must provide
# a defineInst() method that generates the code for an instruction
# definition.

class Format(object):
    def __init__(self, id, params, code):
        self.id = id
        self.params = params
        label = 'def format ' + id
        self.user_code = compile(fixPythonIndentation(code), label, 'exec')
        param_list = string.join(params, ", ")
        f = '''def defInst(_code, _context, %s):
                my_locals = vars().copy()
                exec _code in _context, my_locals
                return my_locals\n''' % param_list
        c = compile(f, label + ' wrapper', 'exec')
        exec c
        self.func = defInst

    def defineInst(self, parser, name, args, lineno):
        parser.updateExportContext()
        context = parser.exportContext.copy()
        if len(name):
            Name = name[0].upper()
            if len(name) > 1:
                Name += name[1:]
        context.update({ 'name' : name, 'Name' : Name })
        try:
            vars = self.func(self.user_code, context, *args[0], **args[1])
        except Exception, exc:
            if debug:
                raise
            error(lineno, 'error defining "%s": %s.' % (name, exc))
        for k in vars.keys():
            if k not in ('header_output', 'decoder_output',
                         'exec_output', 'decode_block'):
                del vars[k]
        return GenCode(parser, **vars)

# Special null format to catch an implicit-format instruction
# definition outside of any format block.
class NoFormat(object):
    def __init__(self):
        self.defaultInst = ''

    def defineInst(self, parser, name, args, lineno):
        error(lineno,
              'instruction definition "%s" with no active format!' % name)

###############
# GenCode class
#
# The GenCode class encapsulates generated code destined for various
# output files.  The header_output and decoder_output attributes are
# strings containing code destined for decoder.hh and decoder.cc
# respectively.  The decode_block attribute contains code to be
# incorporated in the decode function itself (that will also end up in
# decoder.cc).  The exec_output attribute is a dictionary with a key
# for each CPU model name; the value associated with a particular key
# is the string of code for that CPU model's exec.cc file.  The
# has_decode_default attribute is used in the decode block to allow
# explicit default clauses to override default default clauses.

class GenCode(object):
    # Constructor.  At this point we substitute out all CPU-specific
    # symbols.  For the exec output, these go into the per-model
    # dictionary.  For all other output types they get collapsed into
    # a single string.
    def __init__(self, parser,
                 header_output = '', decoder_output = '', exec_output = '',
                 decode_block = '', has_decode_default = False):
        self.parser = parser
        self.header_output = parser.expandCpuSymbolsToString(header_output)
        self.decoder_output = parser.expandCpuSymbolsToString(decoder_output)
        self.exec_output = exec_output
        self.decode_block = decode_block
        self.has_decode_default = has_decode_default

    # Write these code chunks out to the filesystem.  They will be properly
    # interwoven by the write_top_level_files().
    def emit(self):
        if self.header_output:
            self.parser.get_file('header').write(self.header_output)
        if self.decoder_output:
            self.parser.get_file('decoder').write(self.decoder_output)
        if self.exec_output:
            self.parser.get_file('exec').write(self.exec_output)
        if self.decode_block:
            self.parser.get_file('decode_block').write(self.decode_block)

    # Override '+' operator: generate a new GenCode object that
    # concatenates all the individual strings in the operands.
    def __add__(self, other):
        return GenCode(self.parser,
                       self.header_output + other.header_output,
                       self.decoder_output + other.decoder_output,
                       self.exec_output + other.exec_output,
                       self.decode_block + other.decode_block,
                       self.has_decode_default or other.has_decode_default)

    # Prepend a string (typically a comment) to all the strings.
    def prepend_all(self, pre):
        self.header_output = pre + self.header_output
        self.decoder_output  = pre + self.decoder_output
        self.decode_block = pre + self.decode_block
        self.exec_output  = pre + self.exec_output

    # Wrap the decode block in a pair of strings (e.g., 'case foo:'
    # and 'break;').  Used to build the big nested switch statement.
    def wrap_decode_block(self, pre, post = ''):
        self.decode_block = pre + indent(self.decode_block) + post

#####################################################################
#
#                      Bitfield Operator Support
#
#####################################################################

bitOp1ArgRE = re.compile(r'<\s*(\w+)\s*:\s*>')

bitOpWordRE = re.compile(r'(?<![\w\.])([\w\.]+)<\s*(\w+)\s*:\s*(\w+)\s*>')
bitOpExprRE = re.compile(r'\)<\s*(\w+)\s*:\s*(\w+)\s*>')

def substBitOps(code):
    # first convert single-bit selectors to two-index form
    # i.e., <n> --> <n:n>
    code = bitOp1ArgRE.sub(r'<\1:\1>', code)
    # simple case: selector applied to ID (name)
    # i.e., foo<a:b> --> bits(foo, a, b)
    code = bitOpWordRE.sub(r'bits(\1, \2, \3)', code)
    # if selector is applied to expression (ending in ')'),
    # we need to search backward for matching '('
    match = bitOpExprRE.search(code)
    while match:
        exprEnd = match.start()
        here = exprEnd - 1
        nestLevel = 1
        while nestLevel > 0:
            if code[here] == '(':
                nestLevel -= 1
            elif code[here] == ')':
                nestLevel += 1
            here -= 1
            if here < 0:
                sys.exit("Didn't find '('!")
        exprStart = here+1
        newExpr = r'bits(%s, %s, %s)' % (code[exprStart:exprEnd+1],
                                         match.group(1), match.group(2))
        code = code[:exprStart] + newExpr + code[match.end():]
        match = bitOpExprRE.search(code)
    return code


#####################################################################
#
#                             Code Parser
#
# The remaining code is the support for automatically extracting
# instruction characteristics from pseudocode.
#
#####################################################################

# Force the argument to be a list.  Useful for flags, where a caller
# can specify a singleton flag or a list of flags.  Also usful for
# converting tuples to lists so they can be modified.
def makeList(arg):
    if isinstance(arg, list):
        return arg
    elif isinstance(arg, tuple):
        return list(arg)
    elif not arg:
        return []
    else:
        return [ arg ]

class Operand(object):
    '''Base class for operand descriptors.  An instance of this class
    (or actually a class derived from this one) represents a specific
    operand for a code block (e.g, "Rc.sq" as a dest). Intermediate
    derived classes encapsulates the traits of a particular operand
    type (e.g., "32-bit integer register").'''

    def buildReadCode(self, func = None):
        subst_dict = {"name": self.base_name,
                      "func": func,
                      "reg_idx": self.reg_spec,
                      "ctype": self.ctype}
        if hasattr(self, 'src_reg_idx'):
            subst_dict['op_idx'] = self.src_reg_idx
        code = self.read_code % subst_dict
        return '%s = %s;\n' % (self.base_name, code)

    def buildWriteCode(self, func = None):
        subst_dict = {"name": self.base_name,
                      "func": func,
                      "reg_idx": self.reg_spec,
                      "ctype": self.ctype,
                      "final_val": self.base_name}
        if hasattr(self, 'dest_reg_idx'):
            subst_dict['op_idx'] = self.dest_reg_idx
        code = self.write_code % subst_dict
        return '''
        {
            %s final_val = %s;
            %s;
            if (traceData) { traceData->setData(final_val); }
        }''' % (self.dflt_ctype, self.base_name, code)

    def __init__(self, parser, full_name, ext, is_src, is_dest):
        self.full_name = full_name
        self.ext = ext
        self.is_src = is_src
        self.is_dest = is_dest
        # The 'effective extension' (eff_ext) is either the actual
        # extension, if one was explicitly provided, or the default.
        if ext:
            self.eff_ext = ext
        elif hasattr(self, 'dflt_ext'):
            self.eff_ext = self.dflt_ext

        if hasattr(self, 'eff_ext'):
            self.ctype = parser.operandTypeMap[self.eff_ext]

    # Finalize additional fields (primarily code fields).  This step
    # is done separately since some of these fields may depend on the
    # register index enumeration that hasn't been performed yet at the
    # time of __init__(). The register index enumeration is affected
    # by predicated register reads/writes. Hence, we forward the flags
    # that indicate whether or not predication is in use.
    def finalize(self, predRead, predWrite):
        self.flags = self.getFlags()
        self.constructor = self.makeConstructor(predRead, predWrite)
        self.op_decl = self.makeDecl()

        if self.is_src:
            self.op_rd = self.makeRead(predRead)
            self.op_src_decl = self.makeDecl()
        else:
            self.op_rd = ''
            self.op_src_decl = ''

        if self.is_dest:
            self.op_wb = self.makeWrite(predWrite)
            self.op_dest_decl = self.makeDecl()
        else:
            self.op_wb = ''
            self.op_dest_decl = ''

    def isMem(self):
        return 0

    def isReg(self):
        return 0

    def isFloatReg(self):
        return 0

    def isIntReg(self):
        return 0

    def isCCReg(self):
        return 0

    def isControlReg(self):
        return 0

    def isPCState(self):
        return 0

    def isPCPart(self):
        return self.isPCState() and self.reg_spec

    def hasReadPred(self):
        return self.read_predicate != None

    def hasWritePred(self):
        return self.write_predicate != None

    def getFlags(self):
        # note the empty slice '[:]' gives us a copy of self.flags[0]
        # instead of a reference to it
        my_flags = self.flags[0][:]
        if self.is_src:
            my_flags += self.flags[1]
        if self.is_dest:
            my_flags += self.flags[2]
        return my_flags

    def makeDecl(self):
        # Note that initializations in the declarations are solely
        # to avoid 'uninitialized variable' errors from the compiler.
        return self.ctype + ' ' + self.base_name + ' = 0;\n';

class IntRegOperand(Operand):
    def isReg(self):
        return 1

    def isIntReg(self):
        return 1

    def makeConstructor(self, predRead, predWrite):
        c_src = ''
        c_dest = ''

        if self.is_src:
            c_src = '\n\t_srcRegIdx[_numSrcRegs++] = %s;' % (self.reg_spec)
            if self.hasReadPred():
                c_src = '\n\tif (%s) {%s\n\t}' % \
                        (self.read_predicate, c_src)

        if self.is_dest:
            c_dest = '\n\t_destRegIdx[_numDestRegs++] = %s;' % \
                    (self.reg_spec)
            c_dest += '\n\t_numIntDestRegs++;'
            if self.hasWritePred():
                c_dest = '\n\tif (%s) {%s\n\t}' % \
                         (self.write_predicate, c_dest)

        return c_src + c_dest

    def makeRead(self, predRead):
        if (self.ctype == 'float' or self.ctype == 'double'):
            error('Attempt to read integer register as FP')
        if self.read_code != None:
            return self.buildReadCode('readIntRegOperand')

        int_reg_val = ''
        if predRead:
            int_reg_val = 'xc->readIntRegOperand(this, _sourceIndex++)'
            if self.hasReadPred():
                int_reg_val = '(%s) ? %s : 0' % \
                              (self.read_predicate, int_reg_val)
        else:
            int_reg_val = 'xc->readIntRegOperand(this, %d)' % self.src_reg_idx

        return '%s = %s;\n' % (self.base_name, int_reg_val)

    def makeWrite(self, predWrite):
        if (self.ctype == 'float' or self.ctype == 'double'):
            error('Attempt to write integer register as FP')
        if self.write_code != None:
            return self.buildWriteCode('setIntRegOperand')

        if predWrite:
            wp = 'true'
            if self.hasWritePred():
                wp = self.write_predicate

            wcond = 'if (%s)' % (wp)
            windex = '_destIndex++'
        else:
            wcond = ''
            windex = '%d' % self.dest_reg_idx

        wb = '''
        %s
        {
            %s final_val = %s;
            xc->setIntRegOperand(this, %s, final_val);\n
            if (traceData) { traceData->setData(final_val); }
        }''' % (wcond, self.ctype, self.base_name, windex)

        return wb

class FloatRegOperand(Operand):
    def isReg(self):
        return 1

    def isFloatReg(self):
        return 1

    def makeConstructor(self, predRead, predWrite):
        c_src = ''
        c_dest = ''

        if self.is_src:
            c_src = '\n\t_srcRegIdx[_numSrcRegs++] = %s + FP_Reg_Base;' % \
                    (self.reg_spec)

        if self.is_dest:
            c_dest = \
              '\n\t_destRegIdx[_numDestRegs++] = %s + FP_Reg_Base;' % \
              (self.reg_spec)
            c_dest += '\n\t_numFPDestRegs++;'

        return c_src + c_dest

    def makeRead(self, predRead):
        bit_select = 0
        if (self.ctype == 'float' or self.ctype == 'double'):
            func = 'readFloatRegOperand'
        else:
            func = 'readFloatRegOperandBits'
        if self.read_code != None:
            return self.buildReadCode(func)

        if predRead:
            rindex = '_sourceIndex++'
        else:
            rindex = '%d' % self.src_reg_idx

        return '%s = xc->%s(this, %s);\n' % \
            (self.base_name, func, rindex)

    def makeWrite(self, predWrite):
        if (self.ctype == 'float' or self.ctype == 'double'):
            func = 'setFloatRegOperand'
        else:
            func = 'setFloatRegOperandBits'
        if self.write_code != None:
            return self.buildWriteCode(func)

        if predWrite:
            wp = '_destIndex++'
        else:
            wp = '%d' % self.dest_reg_idx
        wp = 'xc->%s(this, %s, final_val);' % (func, wp)

        wb = '''
        {
            %s final_val = %s;
            %s\n
            if (traceData) { traceData->setData(final_val); }
        }''' % (self.ctype, self.base_name, wp)
        return wb

class CCRegOperand(Operand):
    def isReg(self):
        return 1

    def isCCReg(self):
        return 1

    def makeConstructor(self, predRead, predWrite):
        c_src = ''
        c_dest = ''

        if self.is_src:
            c_src = '\n\t_srcRegIdx[_numSrcRegs++] = %s + CC_Reg_Base;' % \
                     (self.reg_spec)
            if self.hasReadPred():
                c_src = '\n\tif (%s) {%s\n\t}' % \
                        (self.read_predicate, c_src)

        if self.is_dest:
            c_dest = \
              '\n\t_destRegIdx[_numDestRegs++] = %s + CC_Reg_Base;' % \
              (self.reg_spec)
            c_dest += '\n\t_numCCDestRegs++;'
            if self.hasWritePred():
                c_dest = '\n\tif (%s) {%s\n\t}' % \
                         (self.write_predicate, c_dest)

        return c_src + c_dest

    def makeRead(self, predRead):
        if (self.ctype == 'float' or self.ctype == 'double'):
            error('Attempt to read condition-code register as FP')
        if self.read_code != None:
            return self.buildReadCode('readCCRegOperand')

        int_reg_val = ''
        if predRead:
            int_reg_val = 'xc->readCCRegOperand(this, _sourceIndex++)'
            if self.hasReadPred():
                int_reg_val = '(%s) ? %s : 0' % \
                              (self.read_predicate, int_reg_val)
        else:
            int_reg_val = 'xc->readCCRegOperand(this, %d)' % self.src_reg_idx

        return '%s = %s;\n' % (self.base_name, int_reg_val)

    def makeWrite(self, predWrite):
        if (self.ctype == 'float' or self.ctype == 'double'):
            error('Attempt to write condition-code register as FP')
        if self.write_code != None:
            return self.buildWriteCode('setCCRegOperand')

        if predWrite:
            wp = 'true'
            if self.hasWritePred():
                wp = self.write_predicate

            wcond = 'if (%s)' % (wp)
            windex = '_destIndex++'
        else:
            wcond = ''
            windex = '%d' % self.dest_reg_idx

        wb = '''
        %s
        {
            %s final_val = %s;
            xc->setCCRegOperand(this, %s, final_val);\n
            if (traceData) { traceData->setData(final_val); }
        }''' % (wcond, self.ctype, self.base_name, windex)

        return wb

class ControlRegOperand(Operand):
    def isReg(self):
        return 1

    def isControlReg(self):
        return 1

    def makeConstructor(self, predRead, predWrite):
        c_src = ''
        c_dest = ''

        if self.is_src:
            c_src = \
              '\n\t_srcRegIdx[_numSrcRegs++] = %s + Misc_Reg_Base;' % \
              (self.reg_spec)

        if self.is_dest:
            c_dest = \
              '\n\t_destRegIdx[_numDestRegs++] = %s + Misc_Reg_Base;' % \
              (self.reg_spec)

        return c_src + c_dest

    def makeRead(self, predRead):
        bit_select = 0
        if (self.ctype == 'float' or self.ctype == 'double'):
            error('Attempt to read control register as FP')
        if self.read_code != None:
            return self.buildReadCode('readMiscRegOperand')

        if predRead:
            rindex = '_sourceIndex++'
        else:
            rindex = '%d' % self.src_reg_idx

        return '%s = xc->readMiscRegOperand(this, %s);\n' % \
            (self.base_name, rindex)

    def makeWrite(self, predWrite):
        if (self.ctype == 'float' or self.ctype == 'double'):
            error('Attempt to write control register as FP')
        if self.write_code != None:
            return self.buildWriteCode('setMiscRegOperand')

        if predWrite:
            windex = '_destIndex++'
        else:
            windex = '%d' % self.dest_reg_idx

        wb = 'xc->setMiscRegOperand(this, %s, %s);\n' % \
             (windex, self.base_name)
        wb += 'if (traceData) { traceData->setData(%s); }' % \
              self.base_name

        return wb

class MemOperand(Operand):
    def isMem(self):
        return 1

    def makeConstructor(self, predRead, predWrite):
        return ''

    def makeDecl(self):
        # Note that initializations in the declarations are solely
        # to avoid 'uninitialized variable' errors from the compiler.
        # Declare memory data variable.
        return '%s %s = 0;\n' % (self.ctype, self.base_name)

    def makeRead(self, predRead):
        if self.read_code != None:
            return self.buildReadCode()
        return ''

    def makeWrite(self, predWrite):
        if self.write_code != None:
            return self.buildWriteCode()
        return ''

class PCStateOperand(Operand):
    def makeConstructor(self, predRead, predWrite):
        return ''

    def makeRead(self, predRead):
        if self.reg_spec:
            # A component of the PC state.
            return '%s = __parserAutoPCState.%s();\n' % \
                (self.base_name, self.reg_spec)
        else:
            # The whole PC state itself.
            return '%s = xc->pcState();\n' % self.base_name

    def makeWrite(self, predWrite):
        if self.reg_spec:
            # A component of the PC state.
            return '__parserAutoPCState.%s(%s);\n' % \
                (self.reg_spec, self.base_name)
        else:
            # The whole PC state itself.
            return 'xc->pcState(%s);\n' % self.base_name

    def makeDecl(self):
        ctype = 'TheISA::PCState'
        if self.isPCPart():
            ctype = self.ctype
        return "%s %s;\n" % (ctype, self.base_name)

    def isPCState(self):
        return 1

class OperandList(object):
    '''Find all the operands in the given code block.  Returns an operand
    descriptor list (instance of class OperandList).'''
    def __init__(self, parser, code):
        self.items = []
        self.bases = {}
        # delete strings and comments so we don't match on operands inside
        for regEx in (stringRE, commentRE):
            code = regEx.sub('', code)
        # search for operands
        next_pos = 0
        while 1:
            match = parser.operandsRE.search(code, next_pos)
            if not match:
                # no more matches: we're done
                break
            op = match.groups()
            # regexp groups are operand full name, base, and extension
            (op_full, op_base, op_ext) = op
            # if the token following the operand is an assignment, this is
            # a destination (LHS), else it's a source (RHS)
            is_dest = (assignRE.match(code, match.end()) != None)
            is_src = not is_dest
            # see if we've already seen this one
            op_desc = self.find_base(op_base)
            if op_desc:
                if op_desc.ext != op_ext:
                    error('Inconsistent extensions for operand %s' % \
                          op_base)
                op_desc.is_src = op_desc.is_src or is_src
                op_desc.is_dest = op_desc.is_dest or is_dest
            else:
                # new operand: create new descriptor
                op_desc = parser.operandNameMap[op_base](parser,
                    op_full, op_ext, is_src, is_dest)
                self.append(op_desc)
            # start next search after end of current match
            next_pos = match.end()
        self.sort()
        # enumerate source & dest register operands... used in building
        # constructor later
        self.numSrcRegs = 0
        self.numDestRegs = 0
        self.numFPDestRegs = 0
        self.numIntDestRegs = 0
        self.numCCDestRegs = 0
        self.numMiscDestRegs = 0
        self.memOperand = None

        # Flags to keep track if one or more operands are to be read/written
        # conditionally.
        self.predRead = False
        self.predWrite = False

        for op_desc in self.items:
            if op_desc.isReg():
                if op_desc.is_src:
                    op_desc.src_reg_idx = self.numSrcRegs
                    self.numSrcRegs += 1
                if op_desc.is_dest:
                    op_desc.dest_reg_idx = self.numDestRegs
                    self.numDestRegs += 1
                    if op_desc.isFloatReg():
                        self.numFPDestRegs += 1
                    elif op_desc.isIntReg():
                        self.numIntDestRegs += 1
                    elif op_desc.isCCReg():
                        self.numCCDestRegs += 1
                    elif op_desc.isControlReg():
                        self.numMiscDestRegs += 1
            elif op_desc.isMem():
                if self.memOperand:
                    error("Code block has more than one memory operand.")
                self.memOperand = op_desc

            # Check if this operand has read/write predication. If true, then
            # the microop will dynamically index source/dest registers.
            self.predRead = self.predRead or op_desc.hasReadPred()
            self.predWrite = self.predWrite or op_desc.hasWritePred()

        if parser.maxInstSrcRegs < self.numSrcRegs:
            parser.maxInstSrcRegs = self.numSrcRegs
        if parser.maxInstDestRegs < self.numDestRegs:
            parser.maxInstDestRegs = self.numDestRegs
        if parser.maxMiscDestRegs < self.numMiscDestRegs:
            parser.maxMiscDestRegs = self.numMiscDestRegs

        # now make a final pass to finalize op_desc fields that may depend
        # on the register enumeration
        for op_desc in self.items:
            op_desc.finalize(self.predRead, self.predWrite)

    def __len__(self):
        return len(self.items)

    def __getitem__(self, index):
        return self.items[index]

    def append(self, op_desc):
        self.items.append(op_desc)
        self.bases[op_desc.base_name] = op_desc

    def find_base(self, base_name):
        # like self.bases[base_name], but returns None if not found
        # (rather than raising exception)
        return self.bases.get(base_name)

    # internal helper function for concat[Some]Attr{Strings|Lists}
    def __internalConcatAttrs(self, attr_name, filter, result):
        for op_desc in self.items:
            if filter(op_desc):
                result += getattr(op_desc, attr_name)
        return result

    # return a single string that is the concatenation of the (string)
    # values of the specified attribute for all operands
    def concatAttrStrings(self, attr_name):
        return self.__internalConcatAttrs(attr_name, lambda x: 1, '')

    # like concatAttrStrings, but only include the values for the operands
    # for which the provided filter function returns true
    def concatSomeAttrStrings(self, filter, attr_name):
        return self.__internalConcatAttrs(attr_name, filter, '')

    # return a single list that is the concatenation of the (list)
    # values of the specified attribute for all operands
    def concatAttrLists(self, attr_name):
        return self.__internalConcatAttrs(attr_name, lambda x: 1, [])

    # like concatAttrLists, but only include the values for the operands
    # for which the provided filter function returns true
    def concatSomeAttrLists(self, filter, attr_name):
        return self.__internalConcatAttrs(attr_name, filter, [])

    def sort(self):
        self.items.sort(lambda a, b: a.sort_pri - b.sort_pri)

class SubOperandList(OperandList):
    '''Find all the operands in the given code block.  Returns an operand
    descriptor list (instance of class OperandList).'''
    def __init__(self, parser, code, master_list):
        self.items = []
        self.bases = {}
        # delete strings and comments so we don't match on operands inside
        for regEx in (stringRE, commentRE):
            code = regEx.sub('', code)
        # search for operands
        next_pos = 0
        while 1:
            match = parser.operandsRE.search(code, next_pos)
            if not match:
                # no more matches: we're done
                break
            op = match.groups()
            # regexp groups are operand full name, base, and extension
            (op_full, op_base, op_ext) = op
            # find this op in the master list
            op_desc = master_list.find_base(op_base)
            if not op_desc:
                error('Found operand %s which is not in the master list!' \
                      ' This is an internal error' % op_base)
            else:
                # See if we've already found this operand
                op_desc = self.find_base(op_base)
                if not op_desc:
                    # if not, add a reference to it to this sub list
                    self.append(master_list.bases[op_base])

            # start next search after end of current match
            next_pos = match.end()
        self.sort()
        self.memOperand = None
        # Whether the whole PC needs to be read so parts of it can be accessed
        self.readPC = False
        # Whether the whole PC needs to be written after parts of it were
        # changed
        self.setPC = False
        # Whether this instruction manipulates the whole PC or parts of it.
        # Mixing the two is a bad idea and flagged as an error.
        self.pcPart = None

        # Flags to keep track if one or more operands are to be read/written
        # conditionally.
        self.predRead = False
        self.predWrite = False

        for op_desc in self.items:
            if op_desc.isPCPart():
                self.readPC = True
                if op_desc.is_dest:
                    self.setPC = True

            if op_desc.isPCState():
                if self.pcPart is not None:
                    if self.pcPart and not op_desc.isPCPart() or \
                            not self.pcPart and op_desc.isPCPart():
                        error("Mixed whole and partial PC state operands.")
                self.pcPart = op_desc.isPCPart()

            if op_desc.isMem():
                if self.memOperand:
                    error("Code block has more than one memory operand.")
                self.memOperand = op_desc

            # Check if this operand has read/write predication. If true, then
            # the microop will dynamically index source/dest registers.
            self.predRead = self.predRead or op_desc.hasReadPred()
            self.predWrite = self.predWrite or op_desc.hasWritePred()

# Regular expression object to match C++ strings
stringRE = re.compile(r'"([^"\\]|\\.)*"')

# Regular expression object to match C++ comments
# (used in findOperands())
commentRE = re.compile(r'(^)?[^\S\n]*/(?:\*(.*?)\*/[^\S\n]*|/[^\n]*)($)?',
        re.DOTALL | re.MULTILINE)

# Regular expression object to match assignment statements
# (used in findOperands())
assignRE = re.compile(r'\s*=(?!=)', re.MULTILINE)

def makeFlagConstructor(flag_list):
    if len(flag_list) == 0:
        return ''
    # filter out repeated flags
    flag_list.sort()
    i = 1
    while i < len(flag_list):
        if flag_list[i] == flag_list[i-1]:
            del flag_list[i]
        else:
            i += 1
    pre = '\n\tflags['
    post = '] = true;'
    code = pre + string.join(flag_list, post + pre) + post
    return code

# Assume all instruction flags are of the form 'IsFoo'
instFlagRE = re.compile(r'Is.*')

# OpClass constants end in 'Op' except No_OpClass
opClassRE = re.compile(r'.*Op|No_OpClass')

class InstObjParams(object):
    def __init__(self, parser, mnem, class_name, base_class = '',
                 snippets = {}, opt_args = []):
        self.mnemonic = mnem
        self.class_name = class_name
        self.base_class = base_class
        if not isinstance(snippets, dict):
            snippets = {'code' : snippets}
        compositeCode = ' '.join(map(str, snippets.values()))
        self.snippets = snippets

        self.operands = OperandList(parser, compositeCode)

        # The header of the constructor declares the variables to be used
        # in the body of the constructor.
        header = ''
        header += '\n\t_numSrcRegs = 0;'
        header += '\n\t_numDestRegs = 0;'
        header += '\n\t_numFPDestRegs = 0;'
        header += '\n\t_numIntDestRegs = 0;'
        header += '\n\t_numCCDestRegs = 0;'

        self.constructor = header + \
                           self.operands.concatAttrStrings('constructor')

        self.flags = self.operands.concatAttrLists('flags')

        # Make a basic guess on the operand class (function unit type).
        # These are good enough for most cases, and can be overridden
        # later otherwise.
        if 'IsStore' in self.flags:
            self.op_class = 'MemWriteOp'
        elif 'IsLoad' in self.flags or 'IsPrefetch' in self.flags:
            self.op_class = 'MemReadOp'
        elif 'IsFloating' in self.flags:
            self.op_class = 'FloatAddOp'
        else:
            self.op_class = 'IntAluOp'

        # Optional arguments are assumed to be either StaticInst flags
        # or an OpClass value.  To avoid having to import a complete
        # list of these values to match against, we do it ad-hoc
        # with regexps.
        for oa in opt_args:
            if instFlagRE.match(oa):
                self.flags.append(oa)
            elif opClassRE.match(oa):
                self.op_class = oa
            else:
                error('InstObjParams: optional arg "%s" not recognized '
                      'as StaticInst::Flag or OpClass.' % oa)

        # add flag initialization to contructor here to include
        # any flags added via opt_args
        self.constructor += makeFlagConstructor(self.flags)

        # if 'IsFloating' is set, add call to the FP enable check
        # function (which should be provided by isa_desc via a declare)
        if 'IsFloating' in self.flags:
            self.fp_enable_check = 'fault = checkFpEnableFault(xc);'
        else:
            self.fp_enable_check = ''

##############
# Stack: a simple stack object.  Used for both formats (formatStack)
# and default cases (defaultStack).  Simply wraps a list to give more
# stack-like syntax and enable initialization with an argument list
# (as opposed to an argument that's a list).

class Stack(list):
    def __init__(self, *items):
        list.__init__(self, items)

    def push(self, item):
        self.append(item);

    def top(self):
        return self[-1]

#######################
#
# ISA Parser
#   parses ISA DSL and emits C++ headers and source
#

class ISAParser(Grammar):
    def __init__(self, output_dir, cpu_models):
        super(ISAParser, self).__init__()
        self.output_dir = output_dir

        self.filename = None # for output file watermarking/scaremongering

        self.cpuModels = cpu_models

        # variable to hold templates
        self.templateMap = {}

        # This dictionary maps format name strings to Format objects.
        self.formatMap = {}

        # Track open files and, if applicable, how many chunks it has been
        # split into so far.
        self.files = {}
        self.splits = {}

        # isa_name / namespace identifier from namespace declaration.
        # before the namespace declaration, None.
        self.isa_name = None
        self.namespace = None

        # The format stack.
        self.formatStack = Stack(NoFormat())

        # The default case stack.
        self.defaultStack = Stack(None)

        # Stack that tracks current file and line number.  Each
        # element is a tuple (filename, lineno) that records the
        # *current* filename and the line number in the *previous*
        # file where it was included.
        self.fileNameStack = Stack()

        symbols = ('makeList', 're', 'string')
        self.exportContext = dict([(s, eval(s)) for s in symbols])

        self.maxInstSrcRegs = 0
        self.maxInstDestRegs = 0
        self.maxMiscDestRegs = 0

    def __getitem__(self, i):    # Allow object (self) to be
        return getattr(self, i)  # passed to %-substitutions

    # Change the file suffix of a base filename:
    #   (e.g.) decoder.cc -> decoder-g.cc.inc for 'global' outputs
    def suffixize(self, s, sec):
        extn = re.compile('(\.[^\.]+)$') # isolate extension
        if self.namespace:
            return extn.sub(r'-ns\1.inc', s) # insert some text on either side
        else:
            return extn.sub(r'-g\1.inc', s)

    # Get the file object for emitting code into the specified section
    # (header, decoder, exec, decode_block).
    def get_file(self, section):
        if section == 'decode_block':
            filename = 'decode-method.cc.inc'
        else:
            if section == 'header':
                file = 'decoder.hh'
            else:
                file = '%s.cc' % section
            filename = self.suffixize(file, section)
        try:
            return self.files[filename]
        except KeyError: pass

        f = self.open(filename)
        self.files[filename] = f

        # The splittable files are the ones with many independent
        # per-instruction functions - the decoder's instruction constructors
        # and the instruction execution (execute()) methods. These both have
        # the suffix -ns.cc.inc, meaning they are within the namespace part
        # of the ISA, contain object-emitting C++ source, and are included
        # into other top-level files. These are the files that need special
        # #define's to allow parts of them to be compiled separately. Rather
        # than splitting the emissions into separate files, the monolithic
        # output of the ISA parser is maintained, but the value (or lack
        # thereof) of the __SPLIT definition during C preprocessing will
        # select the different chunks. If no 'split' directives are used,
        # the cpp emissions have no effect.
        if re.search('-ns.cc.inc$', filename):
            print >>f, '#if !defined(__SPLIT) || (__SPLIT == 1)'
            self.splits[f] = 1
        # ensure requisite #include's
        elif filename in ['decoder-g.cc.inc', 'exec-g.cc.inc']:
            print >>f, '#include "decoder.hh"'
        elif filename == 'decoder-g.hh.inc':
            print >>f, '#include "base/bitfield.hh"'

        return f

    # Weave together the parts of the different output sections by
    # #include'ing them into some very short top-level .cc/.hh files.
    # These small files make it much clearer how this tool works, since
    # you directly see the chunks emitted as files that are #include'd.
    def write_top_level_files(self):
        dep = self.open('inc.d', bare=True)

        # decoder header - everything depends on this
        file = 'decoder.hh'
        with self.open(file) as f:
            inc = []

            fn = 'decoder-g.hh.inc'
            assert(fn in self.files)
            f.write('#include "%s"\n' % fn)
            inc.append(fn)

            fn = 'decoder-ns.hh.inc'
            assert(fn in self.files)
            f.write('namespace %s {\n#include "%s"\n}\n'
                    % (self.namespace, fn))
            inc.append(fn)

            print >>dep, file+':', ' '.join(inc)

        # decoder method - cannot be split
        file = 'decoder.cc'
        with self.open(file) as f:
            inc = []

            fn = 'decoder-g.cc.inc'
            assert(fn in self.files)
            f.write('#include "%s"\n' % fn)
            inc.append(fn)

            fn = 'decode-method.cc.inc'
            # is guaranteed to have been written for parse to complete
            f.write('#include "%s"\n' % fn)
            inc.append(fn)

            inc.append("decoder.hh")
            print >>dep, file+':', ' '.join(inc)

        extn = re.compile('(\.[^\.]+)$')

        # instruction constructors
        splits = self.splits[self.get_file('decoder')]
        file_ = 'inst-constrs.cc'
        for i in range(1, splits+1):
            if splits > 1:
                file = extn.sub(r'-%d\1' % i, file_)
            else:
                file = file_
            with self.open(file) as f:
                inc = []

                fn = 'decoder-g.cc.inc'
                assert(fn in self.files)
                f.write('#include "%s"\n' % fn)
                inc.append(fn)

                fn = 'decoder-ns.cc.inc'
                assert(fn in self.files)
                print >>f, 'namespace %s {' % self.namespace
                if splits > 1:
                    print >>f, '#define __SPLIT %u' % i
                print >>f, '#include "%s"' % fn
                print >>f, '}'
                inc.append(fn)

                inc.append("decoder.hh")
                print >>dep, file+':', ' '.join(inc)

        # instruction execution per-CPU model
        splits = self.splits[self.get_file('exec')]
        for cpu in self.cpuModels:
            for i in range(1, splits+1):
                if splits > 1:
                    file = extn.sub(r'_%d\1' % i, cpu.filename)
                else:
                    file = cpu.filename
                with self.open(file) as f:
                    inc = []

                    fn = 'exec-g.cc.inc'
                    assert(fn in self.files)
                    f.write('#include "%s"\n' % fn)
                    inc.append(fn)

                    f.write(cpu.includes+"\n")

                    fn = 'exec-ns.cc.inc'
                    assert(fn in self.files)
                    print >>f, 'namespace %s {' % self.namespace
                    print >>f, '#define CPU_EXEC_CONTEXT %s' \
                               % cpu.strings['CPU_exec_context']
                    if splits > 1:
                        print >>f, '#define __SPLIT %u' % i
                    print >>f, '#include "%s"' % fn
                    print >>f, '}'
                    inc.append(fn)

                    inc.append("decoder.hh")
                    print >>dep, file+':', ' '.join(inc)

        # max_inst_regs.hh
        self.update('max_inst_regs.hh',
                    '''namespace %(namespace)s {
    const int MaxInstSrcRegs = %(maxInstSrcRegs)d;
    const int MaxInstDestRegs = %(maxInstDestRegs)d;
    const int MaxMiscDestRegs = %(maxMiscDestRegs)d;\n}\n''' % self)
        print >>dep, 'max_inst_regs.hh:'

        dep.close()


    scaremonger_template ='''// DO NOT EDIT
// This file was automatically generated from an ISA description:
//   %(filename)s

''';

    #####################################################################
    #
    #                                Lexer
    #
    # The PLY lexer module takes two things as input:
    # - A list of token names (the string list 'tokens')
    # - A regular expression describing a match for each token.  The
    #   regexp for token FOO can be provided in two ways:
    #   - as a string variable named t_FOO
    #   - as the doc string for a function named t_FOO.  In this case,
    #     the function is also executed, allowing an action to be
    #     associated with each token match.
    #
    #####################################################################

    # Reserved words.  These are listed separately as they are matched
    # using the same regexp as generic IDs, but distinguished in the
    # t_ID() function.  The PLY documentation suggests this approach.
    reserved = (
        'BITFIELD', 'DECODE', 'DECODER', 'DEFAULT', 'DEF', 'EXEC', 'FORMAT',
        'HEADER', 'LET', 'NAMESPACE', 'OPERAND_TYPES', 'OPERANDS',
        'OUTPUT', 'SIGNED', 'SPLIT', 'TEMPLATE'
        )

    # List of tokens.  The lex module requires this.
    tokens = reserved + (
        # identifier
        'ID',

        # integer literal
        'INTLIT',

        # string literal
        'STRLIT',

        # code literal
        'CODELIT',

        # ( ) [ ] { } < > , ; . : :: *
        'LPAREN', 'RPAREN',
        'LBRACKET', 'RBRACKET',
        'LBRACE', 'RBRACE',
        'LESS', 'GREATER', 'EQUALS',
        'COMMA', 'SEMI', 'DOT', 'COLON', 'DBLCOLON',
        'ASTERISK',

        # C preprocessor directives
        'CPPDIRECTIVE'

    # The following are matched but never returned. commented out to
    # suppress PLY warning
        # newfile directive
    #    'NEWFILE',

        # endfile directive
    #    'ENDFILE'
    )

    # Regular expressions for token matching
    t_LPAREN           = r'\('
    t_RPAREN           = r'\)'
    t_LBRACKET         = r'\['
    t_RBRACKET         = r'\]'
    t_LBRACE           = r'\{'
    t_RBRACE           = r'\}'
    t_LESS             = r'\<'
    t_GREATER          = r'\>'
    t_EQUALS           = r'='
    t_COMMA            = r','
    t_SEMI             = r';'
    t_DOT              = r'\.'
    t_COLON            = r':'
    t_DBLCOLON         = r'::'
    t_ASTERISK         = r'\*'

    # Identifiers and reserved words
    reserved_map = { }
    for r in reserved:
        reserved_map[r.lower()] = r

    def t_ID(self, t):
        r'[A-Za-z_]\w*'
        t.type = self.reserved_map.get(t.value, 'ID')
        return t

    # Integer literal
    def t_INTLIT(self, t):
        r'-?(0x[\da-fA-F]+)|\d+'
        try:
            t.value = int(t.value,0)
        except ValueError:
            error(t, 'Integer value "%s" too large' % t.value)
            t.value = 0
        return t

    # String literal.  Note that these use only single quotes, and
    # can span multiple lines.
    def t_STRLIT(self, t):
        r"(?m)'([^'])+'"
        # strip off quotes
        t.value = t.value[1:-1]
        t.lexer.lineno += t.value.count('\n')
        return t


    # "Code literal"... like a string literal, but delimiters are
    # '{{' and '}}' so they get formatted nicely under emacs c-mode
    def t_CODELIT(self, t):
        r"(?m)\{\{([^\}]|}(?!\}))+\}\}"
        # strip off {{ & }}
        t.value = t.value[2:-2]
        t.lexer.lineno += t.value.count('\n')
        return t

    def t_CPPDIRECTIVE(self, t):
        r'^\#[^\#].*\n'
        t.lexer.lineno += t.value.count('\n')
        return t

    def t_NEWFILE(self, t):
        r'^\#\#newfile\s+"[^"]*"'
        self.fileNameStack.push((t.value[11:-1], t.lexer.lineno))
        t.lexer.lineno = 0

    def t_ENDFILE(self, t):
        r'^\#\#endfile'
        (old_filename, t.lexer.lineno) = self.fileNameStack.pop()

    #
    # The functions t_NEWLINE, t_ignore, and t_error are
    # special for the lex module.
    #

    # Newlines
    def t_NEWLINE(self, t):
        r'\n+'
        t.lexer.lineno += t.value.count('\n')

    # Comments
    def t_comment(self, t):
        r'//.*'

    # Completely ignored characters
    t_ignore = ' \t\x0c'

    # Error handler
    def t_error(self, t):
        error(t, "illegal character '%s'" % t.value[0])
        t.skip(1)

    #####################################################################
    #
    #                                Parser
    #
    # Every function whose name starts with 'p_' defines a grammar
    # rule.  The rule is encoded in the function's doc string, while
    # the function body provides the action taken when the rule is
    # matched.  The argument to each function is a list of the values
    # of the rule's symbols: t[0] for the LHS, and t[1..n] for the
    # symbols on the RHS.  For tokens, the value is copied from the
    # t.value attribute provided by the lexer.  For non-terminals, the
    # value is assigned by the producing rule; i.e., the job of the
    # grammar rule function is to set the value for the non-terminal
    # on the LHS (by assigning to t[0]).
    #####################################################################

    # The LHS of the first grammar rule is used as the start symbol
    # (in this case, 'specification').  Note that this rule enforces
    # that there will be exactly one namespace declaration, with 0 or
    # more global defs/decls before and after it.  The defs & decls
    # before the namespace decl will be outside the namespace; those
    # after will be inside.  The decoder function is always inside the
    # namespace.
    def p_specification(self, t):
        'specification : opt_defs_and_outputs top_level_decode_block'

        for f in self.splits.iterkeys():
            f.write('\n#endif\n')

        for f in self.files.itervalues(): # close ALL the files;
            f.close() # not doing so can cause compilation to fail

        self.write_top_level_files()

        t[0] = True

    # 'opt_defs_and_outputs' is a possibly empty sequence of def and/or
    # output statements. Its productions do the hard work of eventually
    # instantiating a GenCode, which are generally emitted (written to disk)
    # as soon as possible, except for the decode_block, which has to be
    # accumulated into one large function of nested switch/case blocks.
    def p_opt_defs_and_outputs_0(self, t):
        'opt_defs_and_outputs : empty'

    def p_opt_defs_and_outputs_1(self, t):
        'opt_defs_and_outputs : defs_and_outputs'

    def p_defs_and_outputs_0(self, t):
        'defs_and_outputs : def_or_output'

    def p_defs_and_outputs_1(self, t):
        'defs_and_outputs : defs_and_outputs def_or_output'

    # The list of possible definition/output statements.
    # They are all processed as they are seen.
    def p_def_or_output(self, t):
        '''def_or_output : name_decl
                         | def_format
                         | def_bitfield
                         | def_bitfield_struct
                         | def_template
                         | def_operand_types
                         | def_operands
                         | output
                         | global_let
                         | split'''

    # Utility function used by both invocations of splitting - explicit
    # 'split' keyword and split() function inside "let {{ }};" blocks.
    def split(self, sec, write=False):
        assert(sec != 'header' and "header cannot be split")

        f = self.get_file(sec)
        self.splits[f] += 1
        s = '\n#endif\n#if __SPLIT == %u\n' % self.splits[f]
        if write:
            f.write(s)
        else:
            return s

    # split output file to reduce compilation time
    def p_split(self, t):
        'split : SPLIT output_type SEMI'
        assert(self.isa_name and "'split' not allowed before namespace decl")

        self.split(t[2], True)

    def p_output_type(self, t):
        '''output_type : DECODER
                       | HEADER
                       | EXEC'''
        t[0] = t[1]

    # ISA name declaration looks like "namespace <foo>;"
    def p_name_decl(self, t):
        'name_decl : NAMESPACE ID SEMI'
        assert(self.isa_name == None and "Only 1 namespace decl permitted")
        self.isa_name = t[2]
        self.namespace = t[2] + 'Inst'

    # Output blocks 'output <foo> {{...}}' (C++ code blocks) are copied
    # directly to the appropriate output section.

    # Massage output block by substituting in template definitions and
    # bit operators.  We handle '%'s embedded in the string that don't
    # indicate template substitutions (or CPU-specific symbols, which
    # get handled in GenCode) by doubling them first so that the
    # format operation will reduce them back to single '%'s.
    def process_output(self, s):
        s = self.protectNonSubstPercents(s)
        # protects cpu-specific symbols too
        s = self.protectCpuSymbols(s)
        return substBitOps(s % self.templateMap)

    def p_output(self, t):
        'output : OUTPUT output_type CODELIT SEMI'
        kwargs = { t[2]+'_output' : self.process_output(t[3]) }
        GenCode(self, **kwargs).emit()

    # global let blocks 'let {{...}}' (Python code blocks) are
    # executed directly when seen.  Note that these execute in a
    # special variable context 'exportContext' to prevent the code
    # from polluting this script's namespace.
    def p_global_let(self, t):
        'global_let : LET CODELIT SEMI'
        def _split(sec):
            return self.split(sec)
        self.updateExportContext()
        self.exportContext["header_output"] = ''
        self.exportContext["decoder_output"] = ''
        self.exportContext["exec_output"] = ''
        self.exportContext["decode_block"] = ''
        self.exportContext["split"] = _split
        split_setup = '''
def wrap(func):
    def split(sec):
        globals()[sec + '_output'] += func(sec)
    return split
split = wrap(split)
del wrap
'''
        # This tricky setup (immediately above) allows us to just write
        # (e.g.) "split('exec')" in the Python code and the split #ifdef's
        # will automatically be added to the exec_output variable. The inner
        # Python execution environment doesn't know about the split points,
        # so we carefully inject and wrap a closure that can retrieve the
        # next split's #define from the parser and add it to the current
        # emission-in-progress.
        try:
            exec split_setup+fixPythonIndentation(t[2]) in self.exportContext
        except Exception, exc:
            if debug:
                raise
            error(t, 'error: %s in global let block "%s".' % (exc, t[2]))
        GenCode(self,
                header_output=self.exportContext["header_output"],
                decoder_output=self.exportContext["decoder_output"],
                exec_output=self.exportContext["exec_output"],
                decode_block=self.exportContext["decode_block"]).emit()

    # Define the mapping from operand type extensions to C++ types and
    # bit widths (stored in operandTypeMap).
    def p_def_operand_types(self, t):
        'def_operand_types : DEF OPERAND_TYPES CODELIT SEMI'
        try:
            self.operandTypeMap = eval('{' + t[3] + '}')
        except Exception, exc:
            if debug:
                raise
            error(t,
                  'error: %s in def operand_types block "%s".' % (exc, t[3]))

    # Define the mapping from operand names to operand classes and
    # other traits.  Stored in operandNameMap.
    def p_def_operands(self, t):
        'def_operands : DEF OPERANDS CODELIT SEMI'
        if not hasattr(self, 'operandTypeMap'):
            error(t, 'error: operand types must be defined before operands')
        try:
            user_dict = eval('{' + t[3] + '}', self.exportContext)
        except Exception, exc:
            if debug:
                raise
            error(t, 'error: %s in def operands block "%s".' % (exc, t[3]))
        self.buildOperandNameMap(user_dict, t.lexer.lineno)

    # A bitfield definition looks like:
    # 'def [signed] bitfield <ID> [<first>:<last>]'
    # This generates a preprocessor macro in the output file.
    def p_def_bitfield_0(self, t):
        'def_bitfield : DEF opt_signed BITFIELD ID LESS INTLIT COLON INTLIT GREATER SEMI'
        expr = 'bits(machInst, %2d, %2d)' % (t[6], t[8])
        if (t[2] == 'signed'):
            expr = 'sext<%d>(%s)' % (t[6] - t[8] + 1, expr)
        hash_define = '#undef %s\n#define %s\t%s\n' % (t[4], t[4], expr)
        GenCode(self, header_output=hash_define).emit()

    # alternate form for single bit: 'def [signed] bitfield <ID> [<bit>]'
    def p_def_bitfield_1(self, t):
        'def_bitfield : DEF opt_signed BITFIELD ID LESS INTLIT GREATER SEMI'
        expr = 'bits(machInst, %2d, %2d)' % (t[6], t[6])
        if (t[2] == 'signed'):
            expr = 'sext<%d>(%s)' % (1, expr)
        hash_define = '#undef %s\n#define %s\t%s\n' % (t[4], t[4], expr)
        GenCode(self, header_output=hash_define).emit()

    # alternate form for structure member: 'def bitfield <ID> <ID>'
    def p_def_bitfield_struct(self, t):
        'def_bitfield_struct : DEF opt_signed BITFIELD ID id_with_dot SEMI'
        if (t[2] != ''):
            error(t, 'error: structure bitfields are always unsigned.')
        expr = 'machInst.%s' % t[5]
        hash_define = '#undef %s\n#define %s\t%s\n' % (t[4], t[4], expr)
        GenCode(self, header_output=hash_define).emit()

    def p_id_with_dot_0(self, t):
        'id_with_dot : ID'
        t[0] = t[1]

    def p_id_with_dot_1(self, t):
        'id_with_dot : ID DOT id_with_dot'
        t[0] = t[1] + t[2] + t[3]

    def p_opt_signed_0(self, t):
        'opt_signed : SIGNED'
        t[0] = t[1]

    def p_opt_signed_1(self, t):
        'opt_signed : empty'
        t[0] = ''

    def p_def_template(self, t):
        'def_template : DEF TEMPLATE ID CODELIT SEMI'
        if t[3] in self.templateMap:
            print "warning: template %s already defined" % t[3]
        self.templateMap[t[3]] = Template(self, t[4])

    # An instruction format definition looks like
    # "def format <fmt>(<params>) {{...}};"
    def p_def_format(self, t):
        'def_format : DEF FORMAT ID LPAREN param_list RPAREN CODELIT SEMI'
        (id, params, code) = (t[3], t[5], t[7])
        self.defFormat(id, params, code, t.lexer.lineno)

    # The formal parameter list for an instruction format is a
    # possibly empty list of comma-separated parameters.  Positional
    # (standard, non-keyword) parameters must come first, followed by
    # keyword parameters, followed by a '*foo' parameter that gets
    # excess positional arguments (as in Python).  Each of these three
    # parameter categories is optional.
    #
    # Note that we do not support the '**foo' parameter for collecting
    # otherwise undefined keyword args.  Otherwise the parameter list
    # is (I believe) identical to what is supported in Python.
    #
    # The param list generates a tuple, where the first element is a
    # list of the positional params and the second element is a dict
    # containing the keyword params.
    def p_param_list_0(self, t):
        'param_list : positional_param_list COMMA nonpositional_param_list'
        t[0] = t[1] + t[3]

    def p_param_list_1(self, t):
        '''param_list : positional_param_list
                      | nonpositional_param_list'''
        t[0] = t[1]

    def p_positional_param_list_0(self, t):
        'positional_param_list : empty'
        t[0] = []

    def p_positional_param_list_1(self, t):
        'positional_param_list : ID'
        t[0] = [t[1]]

    def p_positional_param_list_2(self, t):
        'positional_param_list : positional_param_list COMMA ID'
        t[0] = t[1] + [t[3]]

    def p_nonpositional_param_list_0(self, t):
        'nonpositional_param_list : keyword_param_list COMMA excess_args_param'
        t[0] = t[1] + t[3]

    def p_nonpositional_param_list_1(self, t):
        '''nonpositional_param_list : keyword_param_list
                                    | excess_args_param'''
        t[0] = t[1]

    def p_keyword_param_list_0(self, t):
        'keyword_param_list : keyword_param'
        t[0] = [t[1]]

    def p_keyword_param_list_1(self, t):
        'keyword_param_list : keyword_param_list COMMA keyword_param'
        t[0] = t[1] + [t[3]]

    def p_keyword_param(self, t):
        'keyword_param : ID EQUALS expr'
        t[0] = t[1] + ' = ' + t[3].__repr__()

    def p_excess_args_param(self, t):
        'excess_args_param : ASTERISK ID'
        # Just concatenate them: '*ID'.  Wrap in list to be consistent
        # with positional_param_list and keyword_param_list.
        t[0] = [t[1] + t[2]]

    # End of format definition-related rules.
    ##############

    #
    # A decode block looks like:
    #       decode <field1> [, <field2>]* [default <inst>] { ... }
    #
    def p_top_level_decode_block(self, t):
        'top_level_decode_block : decode_block'
        codeObj = t[1]
        codeObj.wrap_decode_block('''
StaticInstPtr
%(isa_name)s::Decoder::decodeInst(%(isa_name)s::ExtMachInst machInst)
{
    using namespace %(namespace)s;
''' % self, '}')

        codeObj.emit()

    def p_decode_block(self, t):
        'decode_block : DECODE ID opt_default LBRACE decode_stmt_list RBRACE'
        default_defaults = self.defaultStack.pop()
        codeObj = t[5]
        # use the "default defaults" only if there was no explicit
        # default statement in decode_stmt_list
        if not codeObj.has_decode_default:
            codeObj += default_defaults
        codeObj.wrap_decode_block('switch (%s) {\n' % t[2], '}\n')
        t[0] = codeObj

    # The opt_default statement serves only to push the "default
    # defaults" onto defaultStack.  This value will be used by nested
    # decode blocks, and used and popped off when the current
    # decode_block is processed (in p_decode_block() above).
    def p_opt_default_0(self, t):
        'opt_default : empty'
        # no default specified: reuse the one currently at the top of
        # the stack
        self.defaultStack.push(self.defaultStack.top())
        # no meaningful value returned
        t[0] = None

    def p_opt_default_1(self, t):
        'opt_default : DEFAULT inst'
        # push the new default
        codeObj = t[2]
        codeObj.wrap_decode_block('\ndefault:\n', 'break;\n')
        self.defaultStack.push(codeObj)
        # no meaningful value returned
        t[0] = None

    def p_decode_stmt_list_0(self, t):
        'decode_stmt_list : decode_stmt'
        t[0] = t[1]

    def p_decode_stmt_list_1(self, t):
        'decode_stmt_list : decode_stmt decode_stmt_list'
        if (t[1].has_decode_default and t[2].has_decode_default):
            error(t, 'Two default cases in decode block')
        t[0] = t[1] + t[2]

    #
    # Decode statement rules
    #
    # There are four types of statements allowed in a decode block:
    # 1. Format blocks 'format <foo> { ... }'
    # 2. Nested decode blocks
    # 3. Instruction definitions.
    # 4. C preprocessor directives.


    # Preprocessor directives found in a decode statement list are
    # passed through to the output, replicated to all of the output
    # code streams.  This works well for ifdefs, so we can ifdef out
    # both the declarations and the decode cases generated by an
    # instruction definition.  Handling them as part of the grammar
    # makes it easy to keep them in the right place with respect to
    # the code generated by the other statements.
    def p_decode_stmt_cpp(self, t):
        'decode_stmt : CPPDIRECTIVE'
        t[0] = GenCode(self, t[1], t[1], t[1], t[1])

    # A format block 'format <foo> { ... }' sets the default
    # instruction format used to handle instruction definitions inside
    # the block.  This format can be overridden by using an explicit
    # format on the instruction definition or with a nested format
    # block.
    def p_decode_stmt_format(self, t):
        'decode_stmt : FORMAT push_format_id LBRACE decode_stmt_list RBRACE'
        # The format will be pushed on the stack when 'push_format_id'
        # is processed (see below).  Once the parser has recognized
        # the full production (though the right brace), we're done
        # with the format, so now we can pop it.
        self.formatStack.pop()
        t[0] = t[4]

    # This rule exists so we can set the current format (& push the
    # stack) when we recognize the format name part of the format
    # block.
    def p_push_format_id(self, t):
        'push_format_id : ID'
        try:
            self.formatStack.push(self.formatMap[t[1]])
            t[0] = ('', '// format %s' % t[1])
        except KeyError:
            error(t, 'instruction format "%s" not defined.' % t[1])

    # Nested decode block: if the value of the current field matches
    # the specified constant, do a nested decode on some other field.
    def p_decode_stmt_decode(self, t):
        'decode_stmt : case_label COLON decode_block'
        label = t[1]
        codeObj = t[3]
        # just wrap the decoding code from the block as a case in the
        # outer switch statement.
        codeObj.wrap_decode_block('\n%s:\n' % label)
        codeObj.has_decode_default = (label == 'default')
        t[0] = codeObj

    # Instruction definition (finally!).
    def p_decode_stmt_inst(self, t):
        'decode_stmt : case_label COLON inst SEMI'
        label = t[1]
        codeObj = t[3]
        codeObj.wrap_decode_block('\n%s:' % label, 'break;\n')
        codeObj.has_decode_default = (label == 'default')
        t[0] = codeObj

    # The case label is either a list of one or more constants or
    # 'default'
    def p_case_label_0(self, t):
        'case_label : intlit_list'
        def make_case(intlit):
            if intlit >= 2**32:
                return 'case ULL(%#x)' % intlit
            else:
                return 'case %#x' % intlit
        t[0] = ': '.join(map(make_case, t[1]))

    def p_case_label_1(self, t):
        'case_label : DEFAULT'
        t[0] = 'default'

    #
    # The constant list for a decode case label must be non-empty, but
    # may have one or more comma-separated integer literals in it.
    #
    def p_intlit_list_0(self, t):
        'intlit_list : INTLIT'
        t[0] = [t[1]]

    def p_intlit_list_1(self, t):
        'intlit_list : intlit_list COMMA INTLIT'
        t[0] = t[1]
        t[0].append(t[3])

    # Define an instruction using the current instruction format
    # (specified by an enclosing format block).
    # "<mnemonic>(<args>)"
    def p_inst_0(self, t):
        'inst : ID LPAREN arg_list RPAREN'
        # Pass the ID and arg list to the current format class to deal with.
        currentFormat = self.formatStack.top()
        codeObj = currentFormat.defineInst(self, t[1], t[3], t.lexer.lineno)
        args = ','.join(map(str, t[3]))
        args = re.sub('(?m)^', '//', args)
        args = re.sub('^//', '', args)
        comment = '\n// %s::%s(%s)\n' % (currentFormat.id, t[1], args)
        codeObj.prepend_all(comment)
        t[0] = codeObj

    # Define an instruction using an explicitly specified format:
    # "<fmt>::<mnemonic>(<args>)"
    def p_inst_1(self, t):
        'inst : ID DBLCOLON ID LPAREN arg_list RPAREN'
        try:
            format = self.formatMap[t[1]]
        except KeyError:
            error(t, 'instruction format "%s" not defined.' % t[1])

        codeObj = format.defineInst(self, t[3], t[5], t.lexer.lineno)
        comment = '\n// %s::%s(%s)\n' % (t[1], t[3], t[5])
        codeObj.prepend_all(comment)
        t[0] = codeObj

    # The arg list generates a tuple, where the first element is a
    # list of the positional args and the second element is a dict
    # containing the keyword args.
    def p_arg_list_0(self, t):
        'arg_list : positional_arg_list COMMA keyword_arg_list'
        t[0] = ( t[1], t[3] )

    def p_arg_list_1(self, t):
        'arg_list : positional_arg_list'
        t[0] = ( t[1], {} )

    def p_arg_list_2(self, t):
        'arg_list : keyword_arg_list'
        t[0] = ( [], t[1] )

    def p_positional_arg_list_0(self, t):
        'positional_arg_list : empty'
        t[0] = []

    def p_positional_arg_list_1(self, t):
        'positional_arg_list : expr'
        t[0] = [t[1]]

    def p_positional_arg_list_2(self, t):
        'positional_arg_list : positional_arg_list COMMA expr'
        t[0] = t[1] + [t[3]]

    def p_keyword_arg_list_0(self, t):
        'keyword_arg_list : keyword_arg'
        t[0] = t[1]

    def p_keyword_arg_list_1(self, t):
        'keyword_arg_list : keyword_arg_list COMMA keyword_arg'
        t[0] = t[1]
        t[0].update(t[3])

    def p_keyword_arg(self, t):
        'keyword_arg : ID EQUALS expr'
        t[0] = { t[1] : t[3] }

    #
    # Basic expressions.  These constitute the argument values of
    # "function calls" (i.e. instruction definitions in the decode
    # block) and default values for formal parameters of format
    # functions.
    #
    # Right now, these are either strings, integers, or (recursively)
    # lists of exprs (using Python square-bracket list syntax).  Note
    # that bare identifiers are trated as string constants here (since
    # there isn't really a variable namespace to refer to).
    #
    def p_expr_0(self, t):
        '''expr : ID
                | INTLIT
                | STRLIT
                | CODELIT'''
        t[0] = t[1]

    def p_expr_1(self, t):
        '''expr : LBRACKET list_expr RBRACKET'''
        t[0] = t[2]

    def p_list_expr_0(self, t):
        'list_expr : expr'
        t[0] = [t[1]]

    def p_list_expr_1(self, t):
        'list_expr : list_expr COMMA expr'
        t[0] = t[1] + [t[3]]

    def p_list_expr_2(self, t):
        'list_expr : empty'
        t[0] = []

    #
    # Empty production... use in other rules for readability.
    #
    def p_empty(self, t):
        'empty :'
        pass

    # Parse error handler.  Note that the argument here is the
    # offending *token*, not a grammar symbol (hence the need to use
    # t.value)
    def p_error(self, t):
        if t:
            error(t, "syntax error at '%s'" % t.value)
        else:
            error("unknown syntax error")

    # END OF GRAMMAR RULES

    def updateExportContext(self):

        # create a continuation that allows us to grab the current parser
        def wrapInstObjParams(*args):
            return InstObjParams(self, *args)
        self.exportContext['InstObjParams'] = wrapInstObjParams
        self.exportContext.update(self.templateMap)

    def defFormat(self, id, params, code, lineno):
        '''Define a new format'''

        # make sure we haven't already defined this one
        if id in self.formatMap:
            error(lineno, 'format %s redefined.' % id)

        # create new object and store in global map
        self.formatMap[id] = Format(id, params, code)

    def expandCpuSymbolsToDict(self, template):
        '''Expand template with CPU-specific references into a
        dictionary with an entry for each CPU model name.  The entry
        key is the model name and the corresponding value is the
        template with the CPU-specific refs substituted for that
        model.'''

        # Protect '%'s that don't go with CPU-specific terms
        t = re.sub(r'%(?!\(CPU_)', '%%', template)
        result = {}
        for cpu in self.cpuModels:
            result[cpu.name] = t % cpu.strings
        return result

    def expandCpuSymbolsToString(self, template):
        '''*If* the template has CPU-specific references, return a
        single string containing a copy of the template for each CPU
        model with the corresponding values substituted in.  If the
        template has no CPU-specific references, it is returned
        unmodified.'''

        if template.find('%(CPU_') != -1:
            return reduce(lambda x,y: x+y,
                          self.expandCpuSymbolsToDict(template).values())
        else:
            return template

    def protectCpuSymbols(self, template):
        '''Protect CPU-specific references by doubling the
        corresponding '%'s (in preparation for substituting a different
        set of references into the template).'''

        return re.sub(r'%(?=\(CPU_)', '%%', template)

    def protectNonSubstPercents(self, s):
        '''Protect any non-dict-substitution '%'s in a format string
        (i.e. those not followed by '(')'''

        return re.sub(r'%(?!\()', '%%', s)

    def buildOperandNameMap(self, user_dict, lineno):
        operand_name = {}
        for op_name, val in user_dict.iteritems():

            # Check if extra attributes have been specified.
            if len(val) > 9:
                error(lineno, 'error: too many attributes for operand "%s"' %
                      base_cls_name)

            # Pad val with None in case optional args are missing
            val += (None, None, None, None)
            base_cls_name, dflt_ext, reg_spec, flags, sort_pri, \
            read_code, write_code, read_predicate, write_predicate = val[:9]

            # Canonical flag structure is a triple of lists, where each list
            # indicates the set of flags implied by this operand always, when
            # used as a source, and when used as a dest, respectively.
            # For simplicity this can be initialized using a variety of fairly
            # obvious shortcuts; we convert these to canonical form here.
            if not flags:
                # no flags specified (e.g., 'None')
                flags = ( [], [], [] )
            elif isinstance(flags, str):
                # a single flag: assumed to be unconditional
                flags = ( [ flags ], [], [] )
            elif isinstance(flags, list):
                # a list of flags: also assumed to be unconditional
                flags = ( flags, [], [] )
            elif isinstance(flags, tuple):
                # it's a tuple: it should be a triple,
                # but each item could be a single string or a list
                (uncond_flags, src_flags, dest_flags) = flags
                flags = (makeList(uncond_flags),
                         makeList(src_flags), makeList(dest_flags))

            # Accumulate attributes of new operand class in tmp_dict
            tmp_dict = {}
            attrList = ['reg_spec', 'flags', 'sort_pri',
                        'read_code', 'write_code',
                        'read_predicate', 'write_predicate']
            if dflt_ext:
                dflt_ctype = self.operandTypeMap[dflt_ext]
                attrList.extend(['dflt_ctype', 'dflt_ext'])
            for attr in attrList:
                tmp_dict[attr] = eval(attr)
            tmp_dict['base_name'] = op_name

            # New class name will be e.g. "IntReg_Ra"
            cls_name = base_cls_name + '_' + op_name
            # Evaluate string arg to get class object.  Note that the
            # actual base class for "IntReg" is "IntRegOperand", i.e. we
            # have to append "Operand".
            try:
                base_cls = eval(base_cls_name + 'Operand')
            except NameError:
                error(lineno,
                      'error: unknown operand base class "%s"' % base_cls_name)
            # The following statement creates a new class called
            # <cls_name> as a subclass of <base_cls> with the attributes
            # in tmp_dict, just as if we evaluated a class declaration.
            operand_name[op_name] = type(cls_name, (base_cls,), tmp_dict)

        self.operandNameMap = operand_name

        # Define operand variables.
        operands = user_dict.keys()
        extensions = self.operandTypeMap.keys()

        operandsREString = r'''
        (?<!\w)      # neg. lookbehind assertion: prevent partial matches
        ((%s)(?:_(%s))?)   # match: operand with optional '_' then suffix
        (?!\w)       # neg. lookahead assertion: prevent partial matches
        ''' % (string.join(operands, '|'), string.join(extensions, '|'))

        self.operandsRE = re.compile(operandsREString, re.MULTILINE|re.VERBOSE)

        # Same as operandsREString, but extension is mandatory, and only two
        # groups are returned (base and ext, not full name as above).
        # Used for subtituting '_' for '.' to make C++ identifiers.
        operandsWithExtREString = r'(?<!\w)(%s)_(%s)(?!\w)' \
            % (string.join(operands, '|'), string.join(extensions, '|'))

        self.operandsWithExtRE = \
            re.compile(operandsWithExtREString, re.MULTILINE)

    def substMungedOpNames(self, code):
        '''Munge operand names in code string to make legal C++
        variable names.  This means getting rid of the type extension
        if any.  Will match base_name attribute of Operand object.)'''
        return self.operandsWithExtRE.sub(r'\1', code)

    def mungeSnippet(self, s):
        '''Fix up code snippets for final substitution in templates.'''
        if isinstance(s, str):
            return self.substMungedOpNames(substBitOps(s))
        else:
            return s

    def open(self, name, bare=False):
        '''Open the output file for writing and include scary warning.'''
        filename = os.path.join(self.output_dir, name)
        f = open(filename, 'w')
        if f:
            if not bare:
                f.write(ISAParser.scaremonger_template % self)
        return f

    def update(self, file, contents):
        '''Update the output file only.  Scons should handle the case when
        the new contents are unchanged using its built-in hash feature.'''
        f = self.open(file)
        f.write(contents)
        f.close()

    # This regular expression matches '##include' directives
    includeRE = re.compile(r'^\s*##include\s+"(?P<filename>[^"]*)".*$',
                           re.MULTILINE)

    def replace_include(self, matchobj, dirname):
        """Function to replace a matched '##include' directive with the
        contents of the specified file (with nested ##includes
        replaced recursively).  'matchobj' is an re match object
        (from a match of includeRE) and 'dirname' is the directory
        relative to which the file path should be resolved."""

        fname = matchobj.group('filename')
        full_fname = os.path.normpath(os.path.join(dirname, fname))
        contents = '##newfile "%s"\n%s\n##endfile\n' % \
                   (full_fname, self.read_and_flatten(full_fname))
        return contents

    def read_and_flatten(self, filename):
        """Read a file and recursively flatten nested '##include' files."""

        current_dir = os.path.dirname(filename)
        try:
            contents = open(filename).read()
        except IOError:
            error('Error including file "%s"' % filename)

        self.fileNameStack.push((filename, 0))

        # Find any includes and include them
        def replace(matchobj):
            return self.replace_include(matchobj, current_dir)
        contents = self.includeRE.sub(replace, contents)

        self.fileNameStack.pop()
        return contents

    AlreadyGenerated = {}

    def _parse_isa_desc(self, isa_desc_file):
        '''Read in and parse the ISA description.'''

        # The build system can end up running the ISA parser twice: once to
        # finalize the build dependencies, and then to actually generate
        # the files it expects (in src/arch/$ARCH/generated). This code
        # doesn't do anything different either time, however; the SCons
        # invocations just expect different things. Since this code runs
        # within SCons, we can just remember that we've already run and
        # not perform a completely unnecessary run, since the ISA parser's
        # effect is idempotent.
        if isa_desc_file in ISAParser.AlreadyGenerated:
            return

        # grab the last three path components of isa_desc_file
        self.filename = '/'.join(isa_desc_file.split('/')[-3:])

        # Read file and (recursively) all included files into a string.
        # PLY requires that the input be in a single string so we have to
        # do this up front.
        isa_desc = self.read_and_flatten(isa_desc_file)

        # Initialize filename stack with outer file.
        self.fileNameStack.push((isa_desc_file, 0))

        # Parse.
        self.parse_string(isa_desc)

        ISAParser.AlreadyGenerated[isa_desc_file] = None

    def parse_isa_desc(self, *args, **kwargs):
        try:
            self._parse_isa_desc(*args, **kwargs)
        except ISAParserError, e:
            e.exit(self.fileNameStack)

# Called as script: get args from command line.
# Args are: <path to cpu_models.py> <isa desc file> <output dir> <cpu models>
if __name__ == '__main__':
    execfile(sys.argv[1])  # read in CpuModel definitions
    cpu_models = [CpuModel.dict[cpu] for cpu in sys.argv[4:]]
    ISAParser(sys.argv[3], cpu_models).parse_isa_desc(sys.argv[2])
# Copyright (c) 2003-2005 The Regents of The University of Michigan # Copyright (c) 2013 Advanced Micro Devices, Inc. # All rights reserved. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions are # met: redistributions of source code must retain the above copyright # notice, this list of conditions and the following disclaimer; # redistributions in binary form must reproduce the above copyright # notice, this list of conditions and the following disclaimer in the # documentation and/or other materials provided with the distribution; # neither the name of the copyright holders nor the names of its # contributors may be used to endorse or promote products derived from # this software without specific prior written permission. # # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. # # Authors: <NAME> # get type names ################### # Utility functions # # Indent every line in string 's' by two spaces # (except preprocessor directives). # Used to make nested code blocks look pretty. # #)', '  ', s) # # Munge a somewhat arbitrarily formatted piece of Python code # (e.g. from a format 'let' block) into something whose indentation # will get by the Python parser. # # The two keys here are that Python will give a syntax error if # there's any whitespace at the beginning of the first line, and that # all lines at the same lexical nesting level must have identical # indentation.  Unfortunately the way code literals work, an entire # let block tends to have some initial indentation.  Rather than # trying to figure out what that is and strip it off, we prepend 'if # 1:' to make the let code the nested block inside the if (and have # the parser automatically deal with the indentation for us). # # We don't want to do this if (1) the code block is empty or (2) the # first line of the block doesn't have any whitespace at the front. # get rid of blank lines first Error handler for parser errors # Output formatted to work under Emacs compile-mode.  Optional # 'print_traceback' arg, if set to True, prints a Python stack # backtrace too (can be handy when trying to debug the parser # itself). # Print a Python stack backtrace if requested. # Just call exit. #################### # Template objects. # # Template objects are format strings that allow substitution from # the attribute spaces of other objects (e.g. InstObjParams instances). # Protect non-Python-dict substitutions (e.g. if there's a printf # in the templated C++ code) # CPU-model-specific substitutions are handled later (in GenCode). # Build a dict ('myDict') to use for the template substitution. # Start with the template namespace.  Make a copy since we're # going to modify it. # If we're dealing with an InstObjParams object, we need # to be a little more sophisticated.  The instruction-wide # parameters are already formed, but the parameters which # are only function wide still need to be generated. # The "operands" and "snippets" attributes of the InstObjParams # objects are for internal use and not substitution. # Add in template itself in case it references any # operands explicitly (like Mem) # In case there are predicated register reads and write, declare # the variables for register indicies. It is being assumed that # all the operands in the OperandList are also in the # SubOperandList and in the same order. Otherwise, it is # expected that predication would not be used for the operands. # Compose the op_wb string. If we're going to write back the # PC state because we changed some of its elements, we'll need to # do that as early as possible. That allows later uncoordinated # modifications to the PC to layer appropriately. # if the argument is a dictionary, we just use it. # if the argument is an object, we use its attribute map. # Convert to string.  This handles the case when a template with a # CPU-specific term gets interpolated into another template or into # an output block. ################ # Format object. # # A format object encapsulates an instruction format.  It must provide # a defineInst() method that generates the code for an instruction # definition. def defInst(_code, _context, %s):                 my_locals = vars().copy()                 exec _code in _context, my_locals                 return my_locals\n # Special null format to catch an implicit-format instruction # definition outside of any format block. ############### # GenCode class # # The GenCode class encapsulates generated code destined for various # output files.  The header_output and decoder_output attributes are # strings containing code destined for decoder.hh and decoder.cc # respectively.  The decode_block attribute contains code to be # incorporated in the decode function itself (that will also end up in # decoder.cc).  The exec_output attribute is a dictionary with a key # for each CPU model name; the value associated with a particular key # is the string of code for that CPU model's exec.cc file.  The # has_decode_default attribute is used in the decode block to allow # explicit default clauses to override default default clauses. # Constructor.  At this point we substitute out all CPU-specific # symbols.  For the exec output, these go into the per-model # dictionary.  For all other output types they get collapsed into # a single string. # Write these code chunks out to the filesystem.  They will be properly # interwoven by the write_top_level_files(). # Override '+' operator: generate a new GenCode object that # concatenates all the individual strings in the operands. # Prepend a string (typically a comment) to all the strings. # Wrap the decode block in a pair of strings (e.g., 'case foo:' # and 'break;').  Used to build the big nested switch statement. ##################################################################### # #                      Bitfield Operator Support # ##################################################################### # first convert single-bit selectors to two-index form # i.e., <n> --> <n:n> # simple case: selector applied to ID (name) # i.e., foo<a:b> --> bits(foo, a, b) # if selector is applied to expression (ending in ')'), # we need to search backward for matching '(' ##################################################################### # #                             Code Parser # # The remaining code is the support for automatically extracting # instruction characteristics from pseudocode. # ##################################################################### # Force the argument to be a list.  Useful for flags, where a caller # can specify a singleton flag or a list of flags.  Also usful for # converting tuples to lists so they can be modified. Base class for operand descriptors.  An instance of this class     (or actually a class derived from this one) represents a specific     operand for a code block (e.g, "Rc.sq" as a dest). Intermediate     derived classes encapsulates the traits of a particular operand     type (e.g., "32-bit integer register"). {             %s final_val = %s;             %s;             if (traceData) { traceData->setData(final_val); }         } # The 'effective extension' (eff_ext) is either the actual # extension, if one was explicitly provided, or the default. # Finalize additional fields (primarily code fields).  This step # is done separately since some of these fields may depend on the # register index enumeration that hasn't been performed yet at the # time of __init__(). The register index enumeration is affected # by predicated register reads/writes. Hence, we forward the flags # that indicate whether or not predication is in use. # note the empty slice '[:]' gives us a copy of self.flags[0] # instead of a reference to it # Note that initializations in the declarations are solely # to avoid 'uninitialized variable' errors from the compiler. %s         {             %s final_val = %s;             xc->setIntRegOperand(this, %s, final_val);\n             if (traceData) { traceData->setData(final_val); }         } {             %s final_val = %s;             %s\n             if (traceData) { traceData->setData(final_val); }         } %s         {             %s final_val = %s;             xc->setCCRegOperand(this, %s, final_val);\n             if (traceData) { traceData->setData(final_val); }         } # Note that initializations in the declarations are solely # to avoid 'uninitialized variable' errors from the compiler. # Declare memory data variable. # A component of the PC state. # The whole PC state itself. # A component of the PC state. # The whole PC state itself. Find all the operands in the given code block.  Returns an operand     descriptor list (instance of class OperandList). # delete strings and comments so we don't match on operands inside # search for operands # no more matches: we're done # regexp groups are operand full name, base, and extension # if the token following the operand is an assignment, this is # a destination (LHS), else it's a source (RHS) # see if we've already seen this one # new operand: create new descriptor # start next search after end of current match # enumerate source & dest register operands... used in building # constructor later # Flags to keep track if one or more operands are to be read/written # conditionally. # Check if this operand has read/write predication. If true, then # the microop will dynamically index source/dest registers. # now make a final pass to finalize op_desc fields that may depend # on the register enumeration # like self.bases[base_name], but returns None if not found # (rather than raising exception) # internal helper function for concat[Some]Attr{Strings|Lists} # return a single string that is the concatenation of the (string) # values of the specified attribute for all operands # like concatAttrStrings, but only include the values for the operands # for which the provided filter function returns true # return a single list that is the concatenation of the (list) # values of the specified attribute for all operands # like concatAttrLists, but only include the values for the operands # for which the provided filter function returns true Find all the operands in the given code block.  Returns an operand     descriptor list (instance of class OperandList). # delete strings and comments so we don't match on operands inside # search for operands # no more matches: we're done # regexp groups are operand full name, base, and extension # find this op in the master list # See if we've already found this operand # if not, add a reference to it to this sub list # start next search after end of current match # Whether the whole PC needs to be read so parts of it can be accessed # Whether the whole PC needs to be written after parts of it were # changed # Whether this instruction manipulates the whole PC or parts of it. # Mixing the two is a bad idea and flagged as an error. # Flags to keep track if one or more operands are to be read/written # conditionally. # Check if this operand has read/write predication. If true, then # the microop will dynamically index source/dest registers. # Regular expression object to match C++ strings # Regular expression object to match C++ comments # (used in findOperands()) # Regular expression object to match assignment statements # (used in findOperands()) # filter out repeated flags # Assume all instruction flags are of the form 'IsFoo' # OpClass constants end in 'Op' except No_OpClass # The header of the constructor declares the variables to be used # in the body of the constructor. # Make a basic guess on the operand class (function unit type). # These are good enough for most cases, and can be overridden # later otherwise. # Optional arguments are assumed to be either StaticInst flags # or an OpClass value.  To avoid having to import a complete # list of these values to match against, we do it ad-hoc # with regexps. # add flag initialization to contructor here to include # any flags added via opt_args # if 'IsFloating' is set, add call to the FP enable check # function (which should be provided by isa_desc via a declare) ############## # Stack: a simple stack object.  Used for both formats (formatStack) # and default cases (defaultStack).  Simply wraps a list to give more # stack-like syntax and enable initialization with an argument list # (as opposed to an argument that's a list). ####################### # # ISA Parser #   parses ISA DSL and emits C++ headers and source # # for output file watermarking/scaremongering # variable to hold templates # This dictionary maps format name strings to Format objects. # Track open files and, if applicable, how many chunks it has been # split into so far. # isa_name / namespace identifier from namespace declaration. # before the namespace declaration, None. # The format stack. # The default case stack. # Stack that tracks current file and line number.  Each # element is a tuple (filename, lineno) that records the # *current* filename and the line number in the *previous* # file where it was included. # Allow object (self) to be # passed to %-substitutions # Change the file suffix of a base filename: #   (e.g.) decoder.cc -> decoder-g.cc.inc for 'global' outputs # isolate extension # insert some text on either side # Get the file object for emitting code into the specified section # (header, decoder, exec, decode_block). # The splittable files are the ones with many independent # per-instruction functions - the decoder's instruction constructors # and the instruction execution (execute()) methods. These both have # the suffix -ns.cc.inc, meaning they are within the namespace part # of the ISA, contain object-emitting C++ source, and are included # into other top-level files. These are the files that need special # #define's to allow parts of them to be compiled separately. Rather # than splitting the emissions into separate files, the monolithic # output of the ISA parser is maintained, but the value (or lack # thereof) of the __SPLIT definition during C preprocessing will # select the different chunks. If no 'split' directives are used, # the cpp emissions have no effect. # ensure requisite #include's # Weave together the parts of the different output sections by # #include'ing them into some very short top-level .cc/.hh files. # These small files make it much clearer how this tool works, since # you directly see the chunks emitted as files that are #include'd. # decoder header - everything depends on this #include "%s"\n}\n' # decoder method - cannot be split # is guaranteed to have been written for parse to complete # instruction constructors # instruction execution per-CPU model # max_inst_regs.hh namespace %(namespace)s {     const int MaxInstSrcRegs = %(maxInstSrcRegs)d;     const int MaxInstDestRegs = %(maxInstDestRegs)d;     const int MaxMiscDestRegs = %(maxMiscDestRegs)d;\n}\n // DO NOT EDIT // This file was automatically generated from an ISA description: //   %(filename)s ##################################################################### # #                                Lexer # # The PLY lexer module takes two things as input: # - A list of token names (the string list 'tokens') # - A regular expression describing a match for each token.  The #   regexp for token FOO can be provided in two ways: #   - as a string variable named t_FOO #   - as the doc string for a function named t_FOO.  In this case, #     the function is also executed, allowing an action to be #     associated with each token match. # ##################################################################### # Reserved words.  These are listed separately as they are matched # using the same regexp as generic IDs, but distinguished in the # t_ID() function.  The PLY documentation suggests this approach. # List of tokens.  The lex module requires this. # identifier # integer literal # string literal # code literal # ( ) [ ] { } < > , ; . : :: * # C preprocessor directives # The following are matched but never returned. commented out to # suppress PLY warning # newfile directive #    'NEWFILE', # endfile directive #    'ENDFILE' # Regular expressions for token matching # Identifiers and reserved words # Integer literal # String literal.  Note that these use only single quotes, and # can span multiple lines. # strip off quotes # "Code literal"... like a string literal, but delimiters are # '{{' and '}}' so they get formatted nicely under emacs c-mode # strip off {{ & }} #[^\#].*\n' #\#newfile\s+"[^"]*"' #\#endfile' # # The functions t_NEWLINE, t_ignore, and t_error are # special for the lex module. # # Newlines # Comments # Completely ignored characters # Error handler ##################################################################### # #                                Parser # # Every function whose name starts with 'p_' defines a grammar # rule.  The rule is encoded in the function's doc string, while # the function body provides the action taken when the rule is # matched.  The argument to each function is a list of the values # of the rule's symbols: t[0] for the LHS, and t[1..n] for the # symbols on the RHS.  For tokens, the value is copied from the # t.value attribute provided by the lexer.  For non-terminals, the # value is assigned by the producing rule; i.e., the job of the # grammar rule function is to set the value for the non-terminal # on the LHS (by assigning to t[0]). ##################################################################### # The LHS of the first grammar rule is used as the start symbol # (in this case, 'specification').  Note that this rule enforces # that there will be exactly one namespace declaration, with 0 or # more global defs/decls before and after it.  The defs & decls # before the namespace decl will be outside the namespace; those # after will be inside.  The decoder function is always inside the # namespace. #endif\n') # close ALL the files; # not doing so can cause compilation to fail # 'opt_defs_and_outputs' is a possibly empty sequence of def and/or # output statements. Its productions do the hard work of eventually # instantiating a GenCode, which are generally emitted (written to disk) # as soon as possible, except for the decode_block, which has to be # accumulated into one large function of nested switch/case blocks. # The list of possible definition/output statements. # They are all processed as they are seen. def_or_output : name_decl                          | def_format                          | def_bitfield                          | def_bitfield_struct                          | def_template                          | def_operand_types                          | def_operands                          | output                          | global_let                          | split # Utility function used by both invocations of splitting - explicit # 'split' keyword and split() function inside "let {{ }};" blocks. #endif\n#if __SPLIT == %u\n' % self.splits[f] # split output file to reduce compilation time output_type : DECODER                        | HEADER                        | EXEC # ISA name declaration looks like "namespace <foo>;" # Output blocks 'output <foo> {{...}}' (C++ code blocks) are copied # directly to the appropriate output section. # Massage output block by substituting in template definitions and # bit operators.  We handle '%'s embedded in the string that don't # indicate template substitutions (or CPU-specific symbols, which # get handled in GenCode) by doubling them first so that the # format operation will reduce them back to single '%'s. # protects cpu-specific symbols too # global let blocks 'let {{...}}' (Python code blocks) are # executed directly when seen.  Note that these execute in a # special variable context 'exportContext' to prevent the code # from polluting this script's namespace. def wrap(func):     def split(sec):         globals()[sec + '_output'] += func(sec)     return split split = wrap(split) del wrap # This tricky setup (immediately above) allows us to just write # (e.g.) "split('exec')" in the Python code and the split #ifdef's # will automatically be added to the exec_output variable. The inner # Python execution environment doesn't know about the split points, # so we carefully inject and wrap a closure that can retrieve the # next split's #define from the parser and add it to the current # emission-in-progress. # Define the mapping from operand type extensions to C++ types and # bit widths (stored in operandTypeMap). # Define the mapping from operand names to operand classes and # other traits.  Stored in operandNameMap. # A bitfield definition looks like: # 'def [signed] bitfield <ID> [<first>:<last>]' # This generates a preprocessor macro in the output file. #define %s\t%s\n' % (t[4], t[4], expr) # alternate form for single bit: 'def [signed] bitfield <ID> [<bit>]' #define %s\t%s\n' % (t[4], t[4], expr) # alternate form for structure member: 'def bitfield <ID> <ID>' #define %s\t%s\n' % (t[4], t[4], expr) # An instruction format definition looks like # "def format <fmt>(<params>) {{...}};" # The formal parameter list for an instruction format is a # possibly empty list of comma-separated parameters.  Positional # (standard, non-keyword) parameters must come first, followed by # keyword parameters, followed by a '*foo' parameter that gets # excess positional arguments (as in Python).  Each of these three # parameter categories is optional. # # Note that we do not support the '**foo' parameter for collecting # otherwise undefined keyword args.  Otherwise the parameter list # is (I believe) identical to what is supported in Python. # # The param list generates a tuple, where the first element is a # list of the positional params and the second element is a dict # containing the keyword params. param_list : positional_param_list                       | nonpositional_param_list nonpositional_param_list : keyword_param_list                                     | excess_args_param # Just concatenate them: '*ID'.  Wrap in list to be consistent # with positional_param_list and keyword_param_list. # End of format definition-related rules. ############## # # A decode block looks like: #       decode <field1> [, <field2>]* [default <inst>] { ... } # StaticInstPtr %(isa_name)s::Decoder::decodeInst(%(isa_name)s::ExtMachInst machInst) {     using namespace %(namespace)s; # use the "default defaults" only if there was no explicit # default statement in decode_stmt_list # The opt_default statement serves only to push the "default # defaults" onto defaultStack.  This value will be used by nested # decode blocks, and used and popped off when the current # decode_block is processed (in p_decode_block() above). # no default specified: reuse the one currently at the top of # the stack # no meaningful value returned # push the new default # no meaningful value returned # # Decode statement rules # # There are four types of statements allowed in a decode block: # 1. Format blocks 'format <foo> { ... }' # 2. Nested decode blocks # 3. Instruction definitions. # 4. C preprocessor directives. # Preprocessor directives found in a decode statement list are # passed through to the output, replicated to all of the output # code streams.  This works well for ifdefs, so we can ifdef out # both the declarations and the decode cases generated by an # instruction definition.  Handling them as part of the grammar # makes it easy to keep them in the right place with respect to # the code generated by the other statements. # A format block 'format <foo> { ... }' sets the default # instruction format used to handle instruction definitions inside # the block.  This format can be overridden by using an explicit # format on the instruction definition or with a nested format # block. # The format will be pushed on the stack when 'push_format_id' # is processed (see below).  Once the parser has recognized # the full production (though the right brace), we're done # with the format, so now we can pop it. # This rule exists so we can set the current format (& push the # stack) when we recognize the format name part of the format # block. # Nested decode block: if the value of the current field matches # the specified constant, do a nested decode on some other field. # just wrap the decoding code from the block as a case in the # outer switch statement. # Instruction definition (finally!). # The case label is either a list of one or more constants or # 'default' #x)' % intlit #x' % intlit # # The constant list for a decode case label must be non-empty, but # may have one or more comma-separated integer literals in it. # # Define an instruction using the current instruction format # (specified by an enclosing format block). # "<mnemonic>(<args>)" # Pass the ID and arg list to the current format class to deal with. # Define an instruction using an explicitly specified format: # "<fmt>::<mnemonic>(<args>)" # The arg list generates a tuple, where the first element is a # list of the positional args and the second element is a dict # containing the keyword args. # # Basic expressions.  These constitute the argument values of # "function calls" (i.e. instruction definitions in the decode # block) and default values for formal parameters of format # functions. # # Right now, these are either strings, integers, or (recursively) # lists of exprs (using Python square-bracket list syntax).  Note # that bare identifiers are trated as string constants here (since # there isn't really a variable namespace to refer to). # expr : ID                 | INTLIT                 | STRLIT                 | CODELIT expr : LBRACKET list_expr RBRACKET # # Empty production... use in other rules for readability. # # Parse error handler.  Note that the argument here is the # offending *token*, not a grammar symbol (hence the need to use # t.value) # END OF GRAMMAR RULES # create a continuation that allows us to grab the current parser Define a new format # make sure we haven't already defined this one # create new object and store in global map Expand template with CPU-specific references into a         dictionary with an entry for each CPU model name.  The entry         key is the model name and the corresponding value is the         template with the CPU-specific refs substituted for that         model. # Protect '%'s that don't go with CPU-specific terms *If* the template has CPU-specific references, return a         single string containing a copy of the template for each CPU         model with the corresponding values substituted in.  If the         template has no CPU-specific references, it is returned         unmodified. Protect CPU-specific references by doubling the         corresponding '%'s (in preparation for substituting a different         set of references into the template). Protect any non-dict-substitution '%'s in a format string         (i.e. those not followed by '(') # Check if extra attributes have been specified. # Pad val with None in case optional args are missing # Canonical flag structure is a triple of lists, where each list # indicates the set of flags implied by this operand always, when # used as a source, and when used as a dest, respectively. # For simplicity this can be initialized using a variety of fairly # obvious shortcuts; we convert these to canonical form here. # no flags specified (e.g., 'None') # a single flag: assumed to be unconditional # a list of flags: also assumed to be unconditional # it's a tuple: it should be a triple, # but each item could be a single string or a list # Accumulate attributes of new operand class in tmp_dict # New class name will be e.g. "IntReg_Ra" # Evaluate string arg to get class object.  Note that the # actual base class for "IntReg" is "IntRegOperand", i.e. we # have to append "Operand". # The following statement creates a new class called # <cls_name> as a subclass of <base_cls> with the attributes # in tmp_dict, just as if we evaluated a class declaration. # Define operand variables. (?<!\w)      # neg. lookbehind assertion: prevent partial matches         ((%s)(?:_(%s))?)   # match: operand with optional '_' then suffix         (?!\w)       # neg. lookahead assertion: prevent partial matches # Same as operandsREString, but extension is mandatory, and only two # groups are returned (base and ext, not full name as above). # Used for subtituting '_' for '.' to make C++ identifiers. Munge operand names in code string to make legal C++         variable names.  This means getting rid of the type extension         if any.  Will match base_name attribute of Operand object.) Fix up code snippets for final substitution in templates. Open the output file for writing and include scary warning. Update the output file only.  Scons should handle the case when         the new contents are unchanged using its built-in hash feature. # This regular expression matches '##include' directives ##include\s+"(?P<filename>[^"]*)".*$', Function to replace a matched '##include' directive with the         contents of the specified file (with nested ##includes         replaced recursively).  'matchobj' is an re match object         (from a match of includeRE) and 'dirname' is the directory         relative to which the file path should be resolved. #newfile "%s"\n%s\n##endfile\n' % \ Read a file and recursively flatten nested '##include' files. # Find any includes and include them Read in and parse the ISA description. # The build system can end up running the ISA parser twice: once to # finalize the build dependencies, and then to actually generate # the files it expects (in src/arch/$ARCH/generated). This code # doesn't do anything different either time, however; the SCons # invocations just expect different things. Since this code runs # within SCons, we can just remember that we've already run and # not perform a completely unnecessary run, since the ISA parser's # effect is idempotent. # grab the last three path components of isa_desc_file # Read file and (recursively) all included files into a string. # PLY requires that the input be in a single string so we have to # do this up front. # Initialize filename stack with outer file. # Parse. # Called as script: get args from command line. # Args are: <path to cpu_models.py> <isa desc file> <output dir> <cpu models> # read in CpuModel definitions