[PATCH] Support APX NF
Jan Beulich
jbeulich@suse.com
Thu Feb 29 13:17:23 GMT 2024
On 29.02.2024 13:41, Cui, Lili wrote:
>
>
>> -----Original Message-----
>> From: Jan Beulich <jbeulich@suse.com>
>> Sent: Thursday, February 29, 2024 8:04 PM
>> To: Cui, Lili <lili.cui@intel.com>
>> Cc: Lu, Hongjiu <hongjiu.lu@intel.com>; binutils@sourceware.org
>> Subject: Re: [PATCH] Support APX NF
>>
>> On 29.02.2024 13:00, Cui, Lili wrote:
>>>> On 27.02.2024 10:01, Cui, Lili wrote:
>>>>> @@ -8860,6 +8880,9 @@ match_template (char mnem_suffix)
>>>>> goto check_operands_345;
>>>>> }
>>>>> else if (t->opcode_space != SPACE_BASE
>>>>> + /* Map0 and map1 are promoted to MAP4 when NF is
>>>> enabled.
>>>>> + */
>>>>> + && !t->opcode_modifier.nf
>>>>> && (t->opcode_space != SPACE_0F
>>>>> /* MOV to/from CR/DR/TR, as an exception, follow
>>>>> the base opcode space encoding model. */
>>>>
>>>> I don't understand this: How does a template permitting NF matter here?
>>>> I could see the immediately preceding "else if" become something
>>>> along the lines of
>>>>
>>>> else if (is_cpu (t, CpuAPX_F) && (i.operands == 3 ||
>>>> i.has_nf))
>>>>
>>>> But I admit I didn't fully think this through. It's just that the
>>>> change as is looks wrong to me.
>>>>
>>>
>>> I was also dissatisfied with this place yesterday and then modified it to:
>>>
>>> else if (t->opcode_space != SPACE_BASE
>>> /* For EVEX-promoted instructions, opcode_space is
>>> promoted to MAP4. */
>>> && (t->opcode_space != SPACE_EVEXMAP4
>>> || t->mnem_off == MN_movbe)
>>> && (t->opcode_space != SPACE_0F
>>> /* MOV to/from CR/DR/TR, as an exception, follow
>>> the base opcode space encoding model. */
>>> || (t->base_opcode | 7) != 0x27))
>>>
>>> For EVEX-promoted instructions, opcode_space is promoted to MAP4. The
>> old judgment no longer fit for EVEX promoted instructions. However, the logic
>> of this place is still not good.
>>
>> So what about my suggestion?
>
> Your suggestion is better, but we need to replace i.has_nf with new judgment, i.has_nf cannot cover instructions like adc, the testcase will be added by another patch.
>
> + else if (is_cpu (t, CpuAPX_F)
> + && (i.operands == 3 || (t->opcode_space == SPACE_EVEXMAP4
> + && t->mnem_off != MN_movbe)))
Ah yes, to cover the non-NF 2-operand forms. But then is the "i.operands == 3"
part actually still needed?
Jan
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