30 Mar
2012
30 Mar
'12
7:40 p.m.
On 30 March 2012 15:22, /dev/ammo42 <mickeytintincolle(a)yahoo.fr> wrote:
On Fri, 30 Mar 2012 15:36:34 +0100
Nix <nix(a)esperi.org.uk> wrote:
Will this impact Trinity on ARM?
Calvin
On 29 Mar 2012, dev stated:
The amd64 specifications include MMX and SSE2 (with 16 SSE registers
instead of 8 in x86), so every amd64 processor can do SSE2. And also,
composite_line_yuv_mmx.S already has a SSE opcode (pextrw).
But you are right, if operations can be easily parallelized we had
better use SSE2, which allows using MMX opcodes on SSE registers which
are 2 times wider than the MMX ones. And allow the use of SSE2 on x86
if cpuid detects its presence.
> On Sat, 24 Mar 2012 10:24:53 -0500
"David C. Rankin" <drankinatty(a)suddenlinkmail.com> wrote:
More generally, if you're rewriting it for x86-64 anyway, keeping it
MMX seems pretty much pointless. Just go all the way to SSE, or
better that SSE2: you'll cut off almost no hardware and be much more
useful in future. (AVX is probably a step too far: a lot of
toolchains don't support it yet, and I don't know anyone with AVX
hardware.) On 03/24/2012 02:35 AM, /dev/ammo42 wrote:
>> Does this mean I'm missing a library that it needs. I can't
>> ready
>> > the assembler code for nothing, so I hope so. What's the
>> > trick?
> From http://www.x86-64.org/documentation/assembly.html :
> push/pop with 32-bit registers are illegal in amd64. You need to
> disable compilation of this file as it is x86 only assembly.
You are good. Thank you. So the source needs a rewrite for x86_64
to eliminate the push/pop. That will be set in the lower priority
column.
Actually a --disable--mmx option is documented on configure.
And for the rewrite, replacing e?x by r?x in assembler files won't
be enough, some other code also has to be changed to accommodate the
different calling conventions (function arguments on linux-x86 are
on the stack, but the first ones on linux-amd64 are in the 64-bit
registers). Perhaps using inline assembly would allow having only
one version of the assembly code.