< processor > (RISC) A processor whose design is based on the rapid execution of a sequence of simple instructions rather than on the provision of a large variety of complex instructions (as in a Complex Instruction Set Computer ).
Features which are generally found in RISC designs are uniform instruction encoding (e.g. the op-code is always in the same bit positions in each instruction which is always one word long), which allows faster decoding; a homogenous register set , allowing any register to be used in any context and simplifying compiler design; and simple addressing mode s with more complex modes replaced by sequences of simple arithmetic instructions.
Examples of (more or less) RISC processors are the Berkeley RISC , HP-PA , Clipper , i960 , AMD 29000 , MIPS R2000 and DEC Alpha . IBM 's first RISC computer was the RT/PC ( IBM 801 ), they now produce the RISC-based RISC System/6000 and SP/2 lines.
Despite Apple Computer 's bogus claims for their PowerPC -based Macintosh es, the first RISC processor used in a personal computer was the Advanced RISC Machine (ARM) used in the Acorn Archimedes .
(1997-06-03)