4 ms·
> interesting that you have a separate row for "66+F2" Yeah that's only for 0F38F0 to 0F38FF. > Re 'custom size "xh"': AVX-512 also has fourth and eighth Als
by bonzini 2y ago
> interesting that you have a separate row for "66+F2"
Yeah that's only for 0F38F0 to 0F38FF.
> Re 'custom size "xh"': AVX-512 also has fourth and eighth
Also AVX for VPMOVSX and VPMOVZX but those are handled differently. I probably should check if xh is actually redundant... EDIT: it's only needed for VCVTPS2PH, which is the only instruction with a half-sized destination.
> I think the prefix decoding is not quite right for x86-64: 26/2e/36/3e are ignored in 64-bit mode
Interesting, I need to check how they interact with the FS/GS prefixes (64/65).
> REX prefixes that don't immediately preceed the opcode (or VEX/EVEX prefix) are ignored
Oh, didn't know that!
- aengelke 2y ago> how they interact with the FS/GS prefixes (64/65) For memory operations, they are ignored: 64-2e-65-3e gives 65 as segment override. (From my memory and the resulting implementation, I did some tests with hardware a few years back.) I do need to check myself how 2e/3e on branches interact with other segment overrides, though.