Re: [Qemu-devel] [RISU RFC PATCH v2 06/14] x86.risu: add MMX instructions

[Richard Henderson]

On 7/10/19 8:32 PM, Jan Bobek wrote:
> On 7/3/19 5:49 PM, Richard Henderson wrote:
>> On 7/1/19 6:35 AM, Jan Bobek wrote:
>>> +MOVQ            MMX     00001111 011 d 1110 !emit { rex(w => 1); modrm(mod 
>>> => MOD_DIRECT, rm => ~REG_ESP); }
>>> +MOVQ_mem        MMX     00001111 011 d 1110 !emit { rex(w => 1); modrm(mod 
>>> => ~MOD_DIRECT); mem(size => 8); }
>>
>> Oh, note that there are only 8 mmx registers, so the respective rex.{r,b} bit
>> can't be set.
> 
> Actually, my CPU chewed it without choking even when the bits were
> set, but it will taken care of in v3.

That's interesting data.

I wonder if it's worth retaining this as a feature in order to check qemu's
implementation?


r~