[Ffmpeg-devel] gcc4 support & MMX fixups (from Debian)
Aurelien Jacobs
aurel
Wed Feb 1 01:39:01 CET 2006
On Wed, 1 Feb 2006 01:26:49 +0100
Pawe? Sikora <pluto at pld-linux.org> wrote:
> Dnia Wednesday, 1 of February 2006 01:08, Aurelien Jacobs napisa?:
> > On Wed, 1 Feb 2006 00:21:56 +0100
> >
> > Pawe? Sikora <pluto at pld-linux.org> wrote:
> > > Dnia Wednesday, 1 of February 2006 00:01, Aurelien Jacobs napisa?:
> > > > > orig: iters = 1000000000, dt = 7.92 [avg]
> > > > > fixed: iters = 1000000000, dt = 7.35 [avg]
> > > > >
> > > > > we gain: ~7.2%
>
> > Oh ! My bad... stupid me. I just forgot the -O3 when compiling !
> > Now here are some better results :
> >
> > orig: iters = 1000000000, dt = 5.04
> > fixed: iters = 1000000000, dt = 5.47
> >
> > So that's still worse for the fixed version, but that's much more
> > reasonable.
> >
> > Here is the asm code resulting of fixed_transpose4x4:
> > (...)
>
> hmmm, the 4.1/4.0 fixed_transpose4x4 are equal but benchmarks differs.
> maybe orig_transpose4x4 has different prologue?
seems so.
> [ 4.1 / -O2 ]
> orig_transpose4x4:
> leal (%rdx,%rdx), %r9d
> leal (%rcx,%rcx), %eax
> movslq %edx,%r11
> movslq %ecx,%r8
> movslq %r9d,%r10
> addl %edx, %r9d
> movslq %eax,%rdx
> addl %ecx, %eax
> movslq %r9d,%r9
> cltq
> #APP
> movd (%rsi), %mm0
> movd (%rsi,%r8), %mm1
> movd (%rsi,%rdx), %mm2
> movd (%rsi,%rax), %mm3
> punpcklbw %mm1, %mm0
> punpcklbw %mm3, %mm2
> movq %mm0, %mm1
> punpcklwd %mm2, %mm0
> punpckhwd %mm2, %mm1
> movd %mm0, (%rdi)
> punpckhdq %mm0, %mm0
> movd %mm0, (%rdi,%r11)
> movd %mm1, (%rdi,%r10)
> punpckhdq %mm1, %mm1
> movd %mm1, (%rdi,%r9)
> #NO_APP
> ret
[ 4.0 / -O2 ]
orig_transpose4x4:
leal (%rdx,%rdx), %r8d
movslq %edx,%r10
leaq (%rcx,%rcx,2), %rax
movslq %r8d,%r9
addl %edx, %r8d
movslq %r8d,%r8
#APP
movd (%rsi), %mm0
movd (%rsi,%rcx), %mm1
movd (%rsi,%rcx,2), %mm2
movd (%rax,%rsi), %mm3
punpcklbw %mm1, %mm0
punpcklbw %mm3, %mm2
movq %mm0, %mm1
punpcklwd %mm2, %mm0
punpckhwd %mm2, %mm1
movd %mm0, (%rdi)
punpckhdq %mm0, %mm0
movd %mm0, (%rdi,%r10)
movd %mm1, (%rdi,%r9)
punpckhdq %mm1, %mm1
movd %mm1, (%rdi,%r8)
#NO_APP
ret
Aurel
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