Reduced Instruction Set Computer

What RISC stands for. A way of structuring microprocessors which lead to higher-performance designs than CISC (ComplexInstructionSetComputer) was capable of. Back in the 80's and early 90's, a great RISC-vs-CISC war was waged in the industry, with numerous RISC architectures (early ARM, SPARC, MIPS, PowerPC) pitted against the two predominant CISC architectures (x86 ExEightySix, MotorolaSixtyEightKay).

In RISC (in theory), you have a set of simple instructions with simple addressing modes, large general-purpose register sets, and memory transfers are separated from arithmetic instructions. Originally, each instruction was a fixed length (aligned to a machine word) and executed in a fixed number of cycles. This a) allows you to minimize the CriticalPath, increasing the CPU frequency you can get; b) makes pipelining and superscalar design tractable, and c) greatly simplifies instruction decoding.

Who won the RiscVsCisc battle? RISC, sort of:


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