more tidying of x86 feature tests

Uros Bizjak ubizjak@gmail.com
Wed Mar 7 20:28:00 GMT 2007


Richard Henderson wrote:
>> Compared with what?
>>     
>
> Bit tests vs ax.  E.g.
>
>         fnstsw  %ax
>         testb   $1, %ah
>         jne     .L5
> vs
>         fnstsw  %ax
>         sahf
>         jb      .L5
>
> Though I guess it really ought not make any difference
> whatsoever, because 64-bit should always use fcomi.
>   
sahf is ATM used in fmod reduction loop where it tests for incomplete 
reduction.

Uros.




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