COMPSCI 61C Lecture Notes - Lecture 8: Instruction Set, Mips Instruction Set, Stored-Program Computer
6 Feb 2017
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Basic job of a cpu: execute lots of instructions. Instructions are the primitive operations that the cpu may execute. The set of instructions a particular cpu implements is an instruction set architecture (isa) Early trend: add more and more instructions to new cpus to do elaborate operations. Vax architecture had an instruction to multiply polynomials. Risc philosophy (cocke ibm, patterson, hennessy, 1980s): reduced instruction set. Keep the instruction set small and simple -> easier to build fast hardware. Let software do complicated operations by composing simpler ones. Riscs mostly same except for one/two silly design decisions. The instruction immediately after an if is always executed. Mips - semiconductor company that built one of the rst commercial risc architectures. We will study mips architecture in some detail. Widely used in embedded apps, x86 little used in embedded, and more embedded computers than pcs. Arm is instead designed for small code size. Unlike hll like c or java, assembly cannot use variables.
