[FFmpeg-devel] [flamefest-start] A little something on MMX/SSE intrinsics

[Zuxy Meng]

Hi,

2008/3/3, Dave Dodge <dododge at dododge.net>:
> On Thu, Feb 28, 2008 at 04:21:48PM +0800, Zuxy Meng wrote:
> > And IA-64 understands MMX and SSE intrinsics too
>
> I think on IA-64 the MMX/SSE instructions are part of the x86
> emulation, which could make them slow.  IA-64 has its own native
> parallel instructions which are similar but can work with its
> normal registers.

Not in that way. ICC will compile MMX/SSE instrinsics to native IA-64
code; not a one-to-one correspondence anyway.

>
> > Anybody ever checked how icc performed on intrinsics?
>
> BTW last I checked, icc on IA-64 didn't support inline assembly at
> all, so intrinsics (or a standalone assembler) were the only option.
> This isn't that surprising if you know anything about the way assembly
> works on that architecture.  One downside is that the intrinsics only
> cover part of the instruction set, so you can run into situations
> where you can't get it to generate the precise instruction and hint
> combination you're after.
>
>                                                  -Dave Dodge
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-- 
Zuxy
Beauty is truth,
While truth is beauty.
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