[FFmpeg-devel] [PATCH v4] mdct15: add assembly optimizations for the 15-point FFT

[Michael Niedermayer]

On Fri, Jun 23, 2017 at 10:35:43PM +0200, Paul B Mahol wrote:
> On 6/23/17, Michael Niedermayer <michael at niedermayer.cc> wrote:
> > On Fri, Jun 23, 2017 at 02:51:37AM +0100, Rostislav Pehlivanov wrote:
> >> c:    1802 decicycles in fft15,16774635 runs,   2581 skips
> >> avx:   865 decicycles in fft15,16776378 runs,    838 skips
> >>
> >> Signed-off-by: Rostislav Pehlivanov <atomnuker at gmail.com>
> >> ---
> >>  libavcodec/mdct15.c          | 182
> >> +++++++++++++++++++++----------------------
> >>  libavcodec/mdct15.h          |  26 +++----
> >>  libavcodec/x86/Makefile      |   2 +
> >>  libavcodec/x86/mdct15.asm    | 137 ++++++++++++++++++++++++++++++++
> >>  libavcodec/x86/mdct15_init.c |  95 ++++++++++++++++++++++
> >>  5 files changed, 333 insertions(+), 109 deletions(-)
> >>  create mode 100644 libavcodec/x86/mdct15.asm
> >>  create mode 100644 libavcodec/x86/mdct15_init.c
> >
> >
> > seems to fail to build here:
> >
> > libavcodec/x86/mdct15.asm:116: error: invalid combination of opcode and
> > operands
> > libavcodec/x86/mdct15.asm:117: error: invalid combination of opcode and
> > operands
> > libavcodec/x86/mdct15.asm:118: error: invalid combination of opcode and
> > operands
> > make: *** [libavcodec/x86/mdct15.o] Error 1
> >
> > X86ASM=nasm
> >
> > nasm -v
> > NASM version 2.10.09 compiled on Dec 29 2013
> 
> Please update your software sometimes, its healthy.

Actually, its the opposit for ffmpeg in that case.

Most developers probably use the latests nasm.
If i update mine too, we would not test with older as frequently
-> code breaking with older nasm would get in -> git would be more
often broken on user systems, ...

its not hard for me to update it at all, i just think its better if
someone (who doesnt need latest) keeps testing with a old one

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

Concerning the gods, I have no means of knowing whether they exist or not
or of what sort they may be, because of the obscurity of the subject, and
the brevity of human life -- Protagoras
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