[FFmpeg-devel] [PATCH] fix compiling VIS assembly on SPARC

Diego Biurrun diego
Tue Sep 18 02:23:32 CEST 2007


On Mon, Sep 17, 2007 at 12:18:00PM +0200, Diego Biurrun wrote:
> On Sun, Sep 16, 2007 at 12:14:01AM -0500, Derek E. Lewis wrote:
> > On Fri, 14 Sep 2007, Balatoni Denes wrote:
> > 
> > > Thanks Derek, that did clear things up for me - because I had no idea what
> > > these obsolote v8plus registers were.
> > 
> > Actually, part of what I said was wrong, but the concept is still the 
> > same: by default, GCC (as of 3.x) builds for SPARCv8. 'v8plus' is simply 
> > 32-bit code, but uses extra registers that SPARCv9 provides over SPARCv8. 
> > This means a binary built for 'v8plus' requires an UltraSPARC or another 
> > SPARCv9-compatible system to execute. It looks like GCC as of version 4.x 
> > defaults to 'v8plus'. I think it was gcc-2.x that built for SPARCv7 by 
> > default. It is probably to our advantage not to assume what architecture 
> > gcc will default to when compiling, and to define some level of SPARC 
> > compliance we expect. A reasonable level would by SPARCv8, IMO, as there 
> > are still some users out there using sun4m systems, which are SPARCv8. Of 
> > course, this has no relevance on your inline VIS code.
> 
> It would be nice if somebody could provide us some VIS detection code
> for configure.  It should be trivial to do, but it's better to have a
> machine for testing it on...

Somebody with some SPARC-fu please fix the attached patch.  I just took
the 23rd assembler line from libavcodec/sparc/simple_idct_vis.c, it
looked as good as any of them ...

Diego
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