[Ffmpeg-devel] H.264 encoder

Rich Felker dalias
Wed Oct 4 19:58:47 CEST 2006


On Wed, Oct 04, 2006 at 07:11:13PM +0200, Christian Iversen wrote:
> On Wednesday 04 October 2006 19:06, Panagiotis Issaris wrote:
> > Hi,
> >
> > On wo, 2006-10-04 at 19:02 +0200, Panagiotis Issaris wrote:
> > >[...]
> > >
> > > > Is this expression equiv. to val--; ?
> > >
> > > Yes.
> >
> > Well. yes, in case val>0.
> 
> Haha, yeah ;)
> 
> Ok, I thought C used logical SHR, so it all makes sense now. Thanks!

It depends on whether the type is signed or unsigned. Actually it's
unspecified for shifts to signed values which are negative, but any
real-world implementation will have correct signed shifts. This is one
of the (fewer, these days, at least) remaining idiocies in the C
standard, akin to the stupidity of allowing a floating-point
implementation where every float expression evaluates to zero..

Rich





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