[FFmpeg-devel] [PATCH] Higher bit-depth x86 SIMD assembly for yadif

Michael Niedermayer michaelni at gmx.at
Fri Jan 27 06:20:11 CET 2012


On Thu, Jan 26, 2012 at 06:40:39PM +0100, James Darnley wrote:
> On 2012-01-23 07:20, Michael Niedermayer wrote:
> >>> @@ -261,6 +263,7 @@ void RENAME(ff_yadif_filter_line_16bit)(uint8_t *dst,
> >>>              PMAXSD(MM"2",MM"1",MM"7")\
> >>>              PMINSD(MM"3",MM"1",MM"7")\
> >>>              PACK(MM"1")\
> >>> +            MOVH" "MM"1, (%[dst])"\
> >>>  \
> >>>              :\
> >>>              :[tmpA] "r"(tmpA),\
> >>> @@ -269,9 +272,10 @@ void RENAME(ff_yadif_filter_line_16bit)(uint8_t *dst,
> >>>               [next] "r"(next),\
> >>>               [prefs]"r"(prefs),\
> >>>               [mrefs]"r"(mrefs),\
> >>> -             [mode] "g"(mode)\
> >>> +             [mode] "g"(mode),\
> >>> +             [dst]  "r"(dst)\
> >>> +            :CLOBBER_LIST\
> >>>          );\
> > 
> > this uses quite a few registers, i suspect it wont reliably compile
> > on x86_32,
> 
> You are, no doubt, correct.  I tried using "=m"(*dst) as an output
> constraint (like in the original code) and that did give me an error
> about not being able to find a
> register.  Specifically:
> > error: can't find a register in class ‘GENERAL_REGS’ while reloading ‘asm’
> > error: ‘asm’ operand has impossible constraints
> 
> Do you have any suggestions?  Or should I just manage a register myself?

ive no specific suggestion, but iam happy with anything that works.
managing registers in a more manual fashion may help but is possibly
not easy.
simply putting the code under #if ARCH_X86_64 or leaving it split
if you plan to convert it to yasm are probably easier.

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Into a blind darkness they enter who follow after the Ignorance,
they as if into a greater darkness enter who devote themselves
to the Knowledge alone. -- Isha Upanishad
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