[chbot] Chchrobotics Digest, Vol 167, Issue 19 "For those of you interested in RISCV"

[Bevin Brett]

Of course originally ALL computers were 'RISC', but as soon as microcode got invented, that went out the window.

Then we had the architectures like the IBM 360, the Digital PDP-11's, and many others.

Then there was a push back to RISC again around 1980

But the Intel Pentium PRO basically put a squash on them.  What it showed was you could put the RISC machine behind a CISC instruction decoder, and reduce your instruction-fetch-time dramatically.

For the future, I expect to see a balance - rather like the DEC Alpha was doing - where you aim for a cheap-to-decode CISC instruction set over a hidden RISC core.  My impression is many of the ARM and Chinese ideas are basically that.   It is cheaper to store the decoder than it is to store the extra instruction bytes needed by a true RISC machine.

https://homes.cs.washington.edu/~lazowska/cra/risc.html#:~:text=The%20roots%20of%20RISC%20lie,contemporary%20machines%20using%20traditional%20architectures.
RISC Architectures - homes.cs.washington.edu<https://homes.cs.washington.edu/~lazowska/cra/risc.html#:~:text=The%20roots%20of%20RISC%20lie,contemporary%20machines%20using%20traditional%20architectures.>
The Microprocessor Revolution The engine of the computer revolution is the microprocessor. It has led to new inventions, such as FAX machines and personal computers, as well as adding intelligence to existing devices, such as wristwatches and automobiles.
homes.cs.washington.edu
/Bevin
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