Re: [PATCH V2 3/8] Support APX GPR32 with extend evex prefix

[Jan Beulich <jbeulich@suse.com>]

On 16.11.2023 16:10, Cui, Lili wrote:
> 
> 
>> -----Original Message-----
>> From: Jan Beulich <jbeulich@suse.com>
>> Sent: Thursday, November 16, 2023 9:58 PM
>> To: Cui, Lili <lili.cui@intel.com>
>> Cc: Lu, Hongjiu <hongjiu.lu@intel.com>; binutils@sourceware.org
>> Subject: Re: [PATCH V2 3/8] Support APX GPR32 with extend evex prefix
>>
>> On 15.11.2023 12:43, Cui, Lili wrote:
>>>> -----Original Message-----
>>>> From: Jan Beulich <jbeulich@suse.com>
>>>> Sent: Wednesday, November 15, 2023 5:12 PM
>>>>
>>>> On 15.11.2023 07:03, Cui, Lili wrote:
>>>>>>> --- /dev/null
>>>>>>> +++ b/opcodes/i386-dis-evex-x86-64.h
>>>>>>> @@ -0,0 +1,140 @@
>>>>>>> +  /* X86_64_EVEX_0F3849 */
>>>>>>> +  {
>>>>>>> +    { Bad_Opcode },
>>>>>>> +    { VEX_LEN_TABLE (VEX_LEN_0F3849_X86_64) },  },
>>>>>>> +  /* X86_64_EVEX_0F384B */
>>>>>>> +  {
>>>>>>> +    { Bad_Opcode },
>>>>>>> +    { VEX_LEN_TABLE (VEX_LEN_0F384B_X86_64) },  },
>>>>>>> +  /* X86_64_EVEX_0F38E0 */
>>>>>>> +  {
>>>>>>> +    { Bad_Opcode },
>>>>>>> +    { "cmpoxadd", { Mdq, Gdq, VexGdq }, PREFIX_DATA },  },
>>>>>>
>>>>>> This and its sibling entries look to again fully match
>>>> X86_64_VEX_0F38E<n>.
>>>>>
>>>>> It cannot be moved to up level, it needs to go through
>>>>> i386-dis-evex-x86-64.h
>>>>
>>>> I didn't suggest to move up a level. I suggested to re-use the
>>>> existing VEX entries.
>>>>
>>>
>>> It's currently in the x86-64 table, it's a bit weird to revisit the x86-64 table,
>> and moving up one level won't work.
>>>
>>> { X86_64_TABLE (X86_64_VEX_0F38E0) }
>>>
>>>   /* X86_64_VEX_0F38E0 */
>>>   {
>>>     { Bad_Opcode },
>>>     { "cmpoxadd", { Mdq, Gdq, VexGdq }, PREFIX_DATA },
>>>   },
>>
>> Again - I never suggested to move up a level. I also didn't suggest to re-visit
>> x86_64_table[]. I merely requested to re-use X86_64_VEX_0F38Ex in the
>> evex_table[] entries, instead of adding 16 (each) identical new entries to
>> x86_64_table[] with 16 new X86_64_EVEX_0F38Ex enumerators.
>>
> 
> We need to go through this virtual table USE_X86_64_EVEX_FROM_VEX_TABLE to mark event_type = evex_from_vex;

Sure, but instead of

    { X86_64_EVEX_FROM_VEX_TABLE (X86_64_EVEX_0F38E0) },

why can't you use

    { X86_64_EVEX_FROM_VEX_TABLE (X86_64_VEX_0F38E0) },

? The handling of USE_X86_64_EVEX_FROM_VEX_TABLE simply falls through
to that of USE_X86_64_TABLE.

Jan