| Message ID | 20170929225829.2890-3-michael@niedermayer.cc |
|---|---|
| State | New |
| Headers | show |
Hi, On Fri, Sep 29, 2017 at 6:58 PM, Michael Niedermayer <michael@niedermayer.cc > wrote: > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > --- > libavcodec/x86/lossless_videoencdsp.asm | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/libavcodec/x86/lossless_videoencdsp.asm > b/libavcodec/x86/lossless_videoencdsp.asm > index a9c7a0a73c..89f20dc4e2 100644 > --- a/libavcodec/x86/lossless_videoencdsp.asm > +++ b/libavcodec/x86/lossless_videoencdsp.asm > @@ -45,7 +45,7 @@ cglobal diff_bytes, 4,5,2, dst, src1, src2, w > ; labels to jump to if w < regsize and w < 0 > %macro DIFF_BYTES_LOOP_PREP 2 > mov i, wq > - and i, -2 * regsize > + and i, -(2 * regsize) > js %2 > jz %1 > add dstq, i > -- > 2.14.2 OK. (Is this a particular version of an assembler and maybe something that should be reported upstream?) Ronald
On Sat, Sep 30, 2017 at 08:50:57AM -0400, Ronald S. Bultje wrote: > Hi, > > On Fri, Sep 29, 2017 at 6:58 PM, Michael Niedermayer <michael@niedermayer.cc > > wrote: > > > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > > --- > > libavcodec/x86/lossless_videoencdsp.asm | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/libavcodec/x86/lossless_videoencdsp.asm > > b/libavcodec/x86/lossless_videoencdsp.asm > > index a9c7a0a73c..89f20dc4e2 100644 > > --- a/libavcodec/x86/lossless_videoencdsp.asm > > +++ b/libavcodec/x86/lossless_videoencdsp.asm > > @@ -45,7 +45,7 @@ cglobal diff_bytes, 4,5,2, dst, src1, src2, w > > ; labels to jump to if w < regsize and w < 0 > > %macro DIFF_BYTES_LOOP_PREP 2 > > mov i, wq > > - and i, -2 * regsize > > + and i, -(2 * regsize) > > js %2 > > jz %1 > > add dstq, i > > -- > > 2.14.2 > > > OK. > > (Is this a particular version of an assembler and maybe something that > should be reported upstream?) this report from 2011 sounds similar: https://bugzilla.nasm.us/show_bug.cgi?id=3311133 the issue is still open NASM version 2.10.09 compiled on Dec 29 2013 and NASM version 2.11.08 are both affected [...]
On Sat, Sep 30, 2017 at 12:58 AM, Michael Niedermayer <michael@niedermayer.cc> wrote: > - and i, -2 * regsize > + and i, -(2 * regsize) regsize is defined to mmsize / 2 in the relevant case so the expression resolves to -2 * 16 / 2 In nasm integers are 64-bit and / is unsigned division (// is signed division). When you perform unsigned division on a negative number you get a large number that doesn't fit inside a 32-bit immediate. E.g. the warning is working as intended. A better fix is to either use parentheses in the regsize definition (e.g. what you'd normally do in an equivalent C define), or use %assign instead of %define. Using // is kind of ugly so I rather avoid that.
On Sun, Oct 01, 2017 at 02:10:41AM +0200, Henrik Gramner wrote: > On Sat, Sep 30, 2017 at 12:58 AM, Michael Niedermayer > <michael@niedermayer.cc> wrote: > > - and i, -2 * regsize > > + and i, -(2 * regsize) > > regsize is defined to mmsize / 2 in the relevant case so the > expression resolves to -2 * 16 / 2 > > In nasm integers are 64-bit and / is unsigned division (// is signed > division). When you perform unsigned division on a negative number you > get a large number that doesn't fit inside a 32-bit immediate. E.g. > the warning is working as intended. > > A better fix is to either use parentheses in the regsize definition > (e.g. what you'd normally do in an equivalent C define), or use yes, thats better, ill push a fix with that thanks > %assign instead of %define. Using // is kind of ugly so I rather avoid > that. > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
diff --git a/libavcodec/x86/lossless_videoencdsp.asm b/libavcodec/x86/lossless_videoencdsp.asm index a9c7a0a73c..89f20dc4e2 100644 --- a/libavcodec/x86/lossless_videoencdsp.asm +++ b/libavcodec/x86/lossless_videoencdsp.asm @@ -45,7 +45,7 @@ cglobal diff_bytes, 4,5,2, dst, src1, src2, w ; labels to jump to if w < regsize and w < 0 %macro DIFF_BYTES_LOOP_PREP 2 mov i, wq - and i, -2 * regsize + and i, -(2 * regsize) js %2 jz %1 add dstq, i
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> --- libavcodec/x86/lossless_videoencdsp.asm | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)