[PATCH 5/8] ntdll: Add detection for PF_SSE_DAZ_MODE_AVAILABLE

[Joris Huizer]

On 10/21/2012 05:49 PM, James Eder wrote:
> On Sat, Oct 20, 2012 at 7:06 PM, Chris Robinson <chris.kcat at gmail.com> wrote:
>> On 10/20/2012 05:40 PM, James Eder wrote:
>>> +    /* Intel says we need a zeroed 16-byte aligned buffer */
>>> +    char buffer[512 + 16];
>>> +    XMM_SAVE_AREA32 *state = (XMM_SAVE_AREA32 *)(((ULONG_PTR)buffer + 15)
>>> & ~15);
>>> +    memset(buffer, 0, sizeof(buffer));
>>> +
>>> +    __asm__ __volatile__( "fxsave %0" : "=m" (*state) : "m" (*state) );
>>
>> Wouldn't this be simpler?
>>
>> DECLSPEC_ALIGN(16) XMM_SAVE_AREA32 state;
>> memset(state, 0, sizeof(state));
>> __asm__ __volatile__("fxsave %0" : "=m" (*&state) : "m" (*&state));
>>
>> May also want to make sure the two structs are packed.
>>
>>
> I used  that alignment method because I saw it done that way other
> places in Wine.  I figured there must have been a good reason for
> doing it that way (issue with some build environments?) but perhaps
> I'm being paranoid.
>
>
I would think the construct is necessary when allocating memory (the 
allocation functions don't allow to require a certain alignment as far 
as I know)
That might be where you saw this being done?