title: What does insn stand for?
body: <p>I need to come up with an x86(-64) disassembler so I started reading the source code for objdump. After searching around a bit I'm in a file, 'ia64-asmtab.h'. Inside is a struct 'ia64_main_table':</p>
  
  <pre><code>struct ia64_main_table
  {
    /* The entry in the string table that corresponds to the name of this
       opcode. */
    unsigned short name_index;
  
    /* The type of opcode; corresponds to the TYPE field in 
       struct ia64_opcode. */
    unsigned char opcode_type;
  
    /* The number of outputs for this opcode. */
    unsigned char num_outputs;
  
    /* The base insn value for this opcode.  It may be modified by completers. */
    ia64_insn opcode;
  
    /* The mask of valid bits in OPCODE. Zeros indicate operand fields. */
    ia64_insn mask;
  
    /* The operands of this instruction.  Corresponds to the OPERANDS field
       in struct ia64_opcode. */
    unsigned char operands[5];
  
    /* The flags for this instruction.  Corresponds to the FLAGS field in
       struct ia64_opcode. */
    short flags;
  
    /* The tree of completers for this instruction; this is an offset into
       completer_table. */
    short completers;
  };
  </code></pre>
  
  <p>A bit of Googling around hasn't shown any useful results and I'm stumped. Does anyone know what 'insn' stands for? I feel like it should stand for instruction, but it also seems to mean something else.</p>