[Libre-soc-dev] next ISA WG RFC

Luke Kenneth Casson Leighton lkcl at lkcl.net
Mon Mar 6 12:10:55 GMT 2023

folks we need to discuss what RFCs should go in next, and plan

my recommendation is to not go above about 5-7 instructions
per RFC, and to group them.  candidates:

* ternlogi, crternlogi, binlut, crbinlut
* average-sum-diff and abs-accumulate, useful for AV
* grevlut, xperm, bitmatrix
* bmask (x86 BMI on steroids) and cprop (carry-propagation)
* bitmask ops (or/and/xor/get) actually shift operations
* crweird operations (powerful interchange between GPR and CR)
* carryless mul/div/mod
* int/fp mv and mv.swizzle/fmv.swizzle

transcendentals and the GF groups are a bit big to tackle at
the moment.

the most obvious priority ones (easiest to justify) would
be the AV ones. there exist already VSX variants.



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