[x264-devel] Detecting CPU capabilities

[Jason Garrett-Glaser]

On Thu, Sep 18, 2008 at 3:19 PM, Andreas <linuxdreas at dslextreme.com> wrote:
> On my AMD X2 systems (Linux, x86_64), x264 shows this string when I start
> encoding:
> x264 [info]: using cpu capabilities: MMX2 SSE2Slow
> Now, according to AMD, the X2 DualCore cpu is "Including support for SSE,
> SSE2, SSE3, MMX™, 3DNow!™ technology and legacy x86 instructions"
>
> Do I have to tell x264 to use SSE3 somehow, and would that have any
> advantage over the current autodetection?

SSE3 isn't used because there is no use for it.  The only SSE3 code is
used solely for the purpose of bypassing Intel's problem of cacheline
splits, and only on a single line of CPUs that benefits (Pentium 4D).

Now, if you can suggest a use of SSE3 besides that, we might
investigate it, but we haven't noticed any other possible uses ;)

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