<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 modes 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 Macintoshes, the first RISC
processor used in a persona