Re: [Qemu-devel] bug in popcnt emulation with some register operand(s)?

[Andriy Gapon <avg@FreeBSD.org>]

on 08/10/2012 12:02 Andriy Gapon said the following:
> on 08/10/2012 10:52 malc said the following:
>> On Mon, 8 Oct 2012, Andriy Gapon wrote:
>>
>>>
>>> I am running Qemu (plain, no kvm, etc) on an AMD 10h machine that
>>> provides popcnt instruction.  Qemu advertises availability of pocnt
>>> to a guest as well.  What I see in the guest that popcnt
>>> 0x20(%r12),%r8 instruction actually placed its result into %rax.
>>> With %rdi and %rax operands the instruction worked fine though.
>>>
>>>
>>
>> Does following work?
> 
> It does!  Thank you very much.

Do you plan to commit this fix?
Is there anything that I should do to make that happen (sooner)?


>> diff --git a/target-i386/translate.c b/target-i386/translate.c
>> index e896abf..c36cc3e 100644
>> --- a/target-i386/translate.c
>> +++ b/target-i386/translate.c
>> @@ -7818,7 +7818,7 @@ static target_ulong disas_insn(DisasContext *s, target_ulong pc_start)
>>              goto illegal_op;
>>  
>>          modrm = cpu_ldub_code(cpu_single_env, s->pc++);
>> -        reg = ((modrm >> 3) & 7);
>> +        reg = ((modrm >> 3) & 7) | rex_r;
>>  
>>          if (s->prefix & PREFIX_DATA)
>>              ot = OT_WORD;
>>
> 
> 


-- 
Andriy Gapon