[Ffmpeg-devel] PATCH Blackfin UNALIGNED_STORES_ARE_BAD in bitstream.h

[Michael Niedermayer]

Hi

On Tue, Apr 17, 2007 at 01:13:04PM -0400, Rich Felker wrote:
> On Tue, Apr 17, 2007 at 06:43:34PM +0200, Michael Niedermayer wrote:
> > Hi
> > 
> > On Tue, Apr 17, 2007 at 11:56:14AM -0400, Rich Felker wrote:
> > > On Tue, Apr 17, 2007 at 05:39:35PM +0200, Michael Niedermayer wrote:
> > > > > Index: bitstream.h
> > > > > ===================================================================
> > > > > --- bitstream.h	(revision 8596)
> > > > > +++ bitstream.h	(working copy)
> > > > > @@ -166,7 +166,7 @@
> > > > >      uint8_t run;
> > > > >  } RL_VLC_ELEM;
> > > > >  
> > > > > -#if defined(ARCH_SPARC) || defined(ARCH_ARMV4L) || defined(ARCH_MIPS)
> > > > > +#if defined(ARCH_SPARC) || defined(ARCH_ARMV4L) || defined(ARCH_MIPS) || defined(ARCH_BFIN)
> > > > >  #define UNALIGNED_STORES_ARE_BAD
> > > > 
> > > > looks ok
> > > 
> > > IMO we should turn this the other way around:
> > > 
> > > #if !defined(ARCH_X86) && !defined(...)
> > > 
> > > Then the code will ALWAYS work, and just be suboptimal on archs we
> > > haven't identified yet, rather than crashing on unknown archs.
> > 
> > i strongly object to this, noone would ever add any architecture besides x86
> > to it, how should anyone even know of this line?
> 
> It can be documented in a porting file or something. But I strongly
> object to having blatently nonportable code in the default build. If I
> were trying to compile ffmpeg on a strange system and not a competent
> coder/debugger, I would have no idea why it crashed and probably just
> assume it was nonportable crapware rather than learning how to
> investigate and "fix" the problem.
> 
> An few alternatives/compromise ideas:
> 
> 1. Enable the nonportable code by default but have a
> --disable-nonportable-assumptions option to configure, or an
> ARCH_GENERIC define included in the above list that configure would
> define when the arch is unknown to inhibit all such optimizations.
> 
> 2. Just have configure print a message directing users to a porting
> document with references to this line and other similar lines when an
> unknown arch is detected.
> 

iam fine with these, iam just strongly against silently disabling it


[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

When you are offended at any man's fault, turn to yourself and study your
own failings. Then you will forget your anger. -- Epictetus
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