all: add GFNI instructions

[mmcloughlin]

Based on #343

Updates #335

[mmcloughlin]

@klauspost It appears the opcodes without V prefix are not recognized by Go assembler:

--- FAIL: TestAssembles (1.24s)
    load_test.go:30: exec: [/opt/hostedtoolcache/go/1.18.8/x64/bin/go tool asm -e -o /tmp/avo2003297476/asm.o /tmp/avo2003297476/asm.s]
    load_test.go:30: output:
        /tmp/avo200329[74](https://github.com/mmcloughlin/avo/actions/runs/3559848371/jobs/5979483745#step:8:75)76/asm.s:841: unrecognized instruction "GF2P8AFFINEINVQB"
        /tmp/avo2003297476/asm.s:842: unrecognized instruction "GF2P8AFFINEINVQB"
        /tmp/avo20032974[76](https://github.com/mmcloughlin/avo/actions/runs/3559848371/jobs/5979483745#step:8:77)/asm.s:845: unrecognized instruction "GF2P8AFFINEQB"
        /tmp/avo2003297476/asm.s:846: unrecognized instruction "GF2P8AFFINEQB"
        /tmp/avo2003297476/asm.s:849: unrecognized instruction "GF2P8MULB"
        /tmp/avo2003297476/asm.s:850: unrecognized instruction "GF2P8MULB"
        asm: assembly of /tmp/avo2003297476/asm.s failed

[codecov-commenter]

Codecov Report

Merging #344 (69eb794) into master (a0ea0f3) will decrease coverage by 0.03%.
The diff coverage is 72.61%.

@@            Coverage Diff             @@
##           master     #344      +/-   ##
==========================================
- Coverage   75.95%   75.92%   -0.04%     
==========================================
  Files          65       65              
  Lines       20633    20694      +61     
==========================================
+ Hits        15672    15711      +39     
- Misses       4879     4901      +22     
  Partials       82       82              

Flag	Coverage Δ
integration	11.92% <0.00%> (-0.04%)	⬇️
unittests	73.01% <72.61%> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
internal/inst/types.go	52.63% <0.00%> (-3.71%)	⬇️
x86/zoptab.go	92.42% <ø> (ø)
build/zinstructions.go	67.65% <60.60%> (-0.03%)	⬇️
internal/load/load.go	95.67% <100.00%> (+0.16%)	⬆️
x86/zctors.go	100.00% <100.00%> (ø)

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[klauspost]

@mmcloughlin Thanks a bunch. Added it to klauspost/reedsolomon#228 - going in after a bit of testing.

Sorry about the extra work. I will try to catch up on what you did so I can give you a more finished update if I should need it in the future.

[mmcloughlin]

@mmcloughlin Thanks a bunch. Added it to klauspost/reedsolomon#228 - going in after a bit of testing.

Sorry about the extra work. I will try to catch up on what you did so I can give you a more finished update if I should need it in the future.

Yeah no worries at all! This was always something I needed to work on, and GFNI turned out to be a nice small example to get things going. Having done this I can return to #234 and finally land it.

Great to see it in klauspost/reedsolomon#228 so quickly.

[vsivsi]

@mmcloughlin See newly updated PRs #234 and #349. Both caught-up with latest master and adopting the opcodesextra mechanism for adding new instructions. Those two PRs plus this one should bring Avo up to all AVX512 features currently supported by the Go assembler.