Re:How Many X86-64 Instructions Are There Anyway?
by CalChris on Sunday April 30, 2017 @11:29PM
(#14235406)
It's ironic that Ditzel went from Berkeley RISC to Bell Labs and helped develop CRISP [1]. This was the invention of the Decoded Instruction Cache which solved the fetch/decode bandwidth problem. You could have a CISC and not have to worry about decode bandwidth. You could have a wide μop and not have to worry about fetch bandwidth.
[1] http://mprc.pku.edu.cn/~liuxianhua/chn/corpus/Notes/articles...
This was also the very brief time when memory was actually faster than the core, making it possible to contemplate things like large fixed-with instruction encodings, since the main bottleneck with the early CISCs was instruction decoding and not fetch bandwidth; it is unlikely that, had this period not existed, RISC would have developed in the way that it had.