[PATCH v3] Support Intel AVX10.2 media instructions

[Jan Beulich]

On 28.09.2024 17:12, Jiang, Haochen wrote:
>> From: Jan Beulich <jbeulich@suse.com>
>> Sent: Wednesday, September 25, 2024 10:42 PM
>>
>> On 25.09.2024 16:39, Haochen Jiang wrote:
>>> --- a/opcodes/i386-opc.tbl
>>> +++ b/opcodes/i386-opc.tbl
>>> @@ -3057,11 +3057,15 @@ vpdpwssd<vnni><sat>, 0x6652|<sat:opc>,
>> <vnni:avx>_VNNI, Modrm|Space0F38|Src1VVVV
>>>
>>>  // {AVX512,AVX}_VNNI instructions end
>>>
>>> +<vnni_vex:int8:int16:attr:reg:mem, $y:_VNNI_INT8:_VNNI_INT16:Vex::,
>> $z:10_2:10_2:Masking|Broadcast|Disp8ShiftVL:RegZMM:Dword>
>>
>> If this really is needed (contrary to previously outlined plans), it
>> wants wrapping across 3 lines (just like is done for other long-ish
>> templates). However, despite you saying something about this in the
>> description, I don't follow why this is needed.
>>
> 
> The problem here is for <vnni> template, which is used for
> AVX512_VNNI/AVX_VNNI, $z comes first due to AVX512_VNNI is the
> ISA introduced earlier and we need to place it before the VEX version
> for table order.
> 
> But for AVX_VNNI_INT8/16 and AVX10.2, VEX version comes first.
> We need $y placed before $z for table order.

Well, yes, with that <vnni> can't be re-used. That's why the purging of
<vnni> is placed the way it is, ahead of the AVX-VNNI-INT{8,16} insns,
which are the ones you mean to extend. You'll want a fresh new <vnni>,
with - as you say - VEX ahead of EVEX. But yes, I clearly partially
misguided you by saying to leave alone lines that are already there; I'm
sorry for that. The two vpdpb<dpb>d<sat> and vpdpw<dpw>d<sat> lines will
need touching, to add use of said 2nd instance of <vnni>. E.g.

vpdpb<dpb>d<vnni><sat>, 0x<dpb:pfx>50|<sat:opc>, AVX<vnni:cpu>, Modrm|Space0F38|Src1VVVV|VexW0|<vnni:attr>|CheckOperandSize|NoSuf, { RegXMM|RegYMM|<vnni:reg>|<vnni:mem>|Unspecified|BaseIndex, RegXMM|RegYMM|<vnni:reg>, RegXMM|RegYMM|<vnni:reg> }

Jan