the processor fetches the instructions from program memory.
the processor fetches the instructions from program memory.
where does the processor fetch the instructions from?
program memory
section::::computer components.:processor.:cache attack.









































to increase the computational power, processors are generally equipped with a cache memory which decreases the memory access latency. below, the figure shows the hierarchy between the processor and the memory. first the processor looks for data in the cache l1, then l2, then in the memory.









































when the data is not where the processor is looking for, it is called a cache-miss. below, pictures show how the processor fetch data when there are two cache levels.
computer security compromised by hardware failure
unlike alpha, sparc, and mips that only allows one register file to load/fetch one operand at the time; it would require multiple register files to achieve superscale. the arm processor on the other hand does not integrate multiple register files to load/fetch instructions. arm gprs have no special purpose to the instruction set (the arm isa does not require accumulator, index, and stack/base points. registers do not have an accumulator and base/stack point can only be used in thumb mode). any gprs can propagate and store multiple instructions independently in smaller code size that is small enough to be able to fit in one register and its architectural register act as a table and shared with all decoder/instructions with simple bank switching between decoders. the major difference between arm and other designs is that arm allows to run on the same general-purpose register with quick bank switching without requiring additional register file in superscalar. despite x86 sharing the same mechanism with arm that its gprs can store any data individually, x86 will confront data dependency if more than three non-related instructions are stored, as its gprs per file are too small (eight in 32 bit mode and 16 in 64 bit, compared to arm's 13 in 32 bit and 31 in 64 bit) for data, and it is impossible to have superscalar without multiple register files to feed to its decoder (x86 code is big and complex compared to arm). because most x86's front-ends have become much larger and much more power hungry than the arm processor in order to be competitive (example: pentium m & core 2 duo, bay trail). some third-party x86 equivalent processors even became noncompetitive with arm due to having no dedicated register file architecture. particularly for amd, cyrix and via that cannot bring any reasonable performance without register renaming and out of order execution, which leave only intel atom to be the only in-order x86 processor core in the mobile competition. this was until the x86 nehalem processor merged both of its integer and floating point register into one single file, and the introduction of a large physical register table and enhanced allocator table in its front-end before renaming in its out-of-order internal core.
register file