[PATCH 3/8] x86: don't use opcode_length to identify pseudo prefixes

[Jan Beulich]

On 22.03.2021 18:55, H.J. Lu wrote:
> On Mon, Mar 22, 2021 at 9:43 AM Jan Beulich <jbeulich@suse.com> wrote:
>> --- a/opcodes/i386-opc.tbl
>> +++ b/opcodes/i386-opc.tbl
>> @@ -849,19 +849,19 @@ rex.wrb, 0x4d, None, 1, Cpu64, No_bSuf|N
>>  rex.wrx, 0x4e, None, 1, Cpu64, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>>  rex.wrxb, 0x4f, None, 1, Cpu64, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>>
>> -// Pseudo prefixes (opcode_length == 0)
>> +// Pseudo prefixes (base_opcode == 0)
>>
>> -{disp8}, Prefix_Disp8, None, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> -{disp16}, Prefix_Disp16, None, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> -{disp32}, Prefix_Disp32, None, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> -{load}, Prefix_Load, None, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> -{store}, Prefix_Store, None, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> -{vex}, Prefix_VEX, None, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> -{vex2}, Prefix_VEX, None, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> -{vex3}, Prefix_VEX3, None, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> -{evex}, Prefix_EVEX, None, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> -{rex}, Prefix_REX, None, 0, Cpu64, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> -{nooptimize}, Prefix_NoOptimize, None, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> +{disp8}, 0, Prefix_Disp8, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> +{disp16}, 0, Prefix_Disp16, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> +{disp32}, 0, Prefix_Disp32, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> +{load}, 0, Prefix_Load, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> +{store}, 0, Prefix_Store, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> +{vex}, 0, Prefix_VEX, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> +{vex2}, 0, Prefix_VEX, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> +{vex3}, 0, Prefix_VEX3, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> +{evex}, 0, Prefix_EVEX, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> +{rex}, 0, Prefix_REX, 0, Cpu64, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
>> +{nooptimize}, 0, Prefix_NoOptimize, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, {}
> 
> Please define an opcode macro for pseudo prefix, something like
> 
> #define PSEUDO_PREFIX 0

Sure. Seeing your request I'm actually considering to go further and
introduce a pseudo-prefix template. Would you be okay with this?

Jan