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→Complex instructions: PIC controllers are not from Amtel. There is little difference between a PIC "add to accumulator" vs. an 8080 "add to accumulator" except addressing mode. Later PICs have memory mapped accumulators, but the architecture would not be considered memory-to-memory. |
→Classification of ISAs: add see also isa comparison |
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==Classification of ISAs==
{{See also|Comparison of instruction set architectures}}
An ISA may be classified in a number of different ways. A common classification is by architectural ''complexity''. A [[complex instruction set computer]] (CISC) has many specialized instructions, some of which may only be rarely used in practical programs. A [[reduced instruction set computer]] (RISC) simplifies the processor by efficiently implementing only the instructions that are frequently used in programs, while the less common operations are implemented as subroutines, having their resulting additional processor execution time offset by infrequent use.<ref>{{cite web |last1=Chen |first1=Crystal |last2=Novick |first2=Greg |last3=Shimano |first3=Kirk |date=December 16, 2006 |title=RISC Architecture: RISC vs. CISC |url=http://cs.stanford.edu/people/eroberts/courses/soco/projects/risc/risccisc/ |url-status=dead |archive-url=https://web.archive.org/web/20150221071744/http://cs.stanford.edu/people/eroberts/courses/soco/projects/risc/risccisc/ |archive-date=February 21, 2015 |access-date=February 21, 2015 |website=cs.stanford.edu}}</ref>
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