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Re: [PATCH] Detect i586 and i686 features at run-time


On Tue, Aug 18, 2015 at 9:20 PM, Mike Frysinger <vapier@gentoo.org> wrote:
> On 18 Aug 2015 11:25, H.J. Lu wrote:
>> We detect i586 and i686 features at run-time by checking CX8 and CMOV
>> CPUID features bits.  We can use these information to select the best
>> implementation in ix86 multiarch.
>
> there are i686's w/out cmov.  shouldn't multiarch implementations that use
> certain insns be tied to those rather than a big knob like "i686" ?
> -mike

For purpose glibc build, i686 has cmov:

[hjl@gnu-tools-1 glibc]$ grep cmov sysdeps/i386/i686/*.S
sysdeps/i386/i686/strcmp.S: cmovbl %ecx, %eax
sysdeps/i386/i686/strtok.S: cmove %eax, %edx
sysdeps/i386/i686/strtok.S: cmovne %ecx, %edx
[hjl@gnu-tools-1 glibc]$
[

-- 
H.J.


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