[FFmpeg-devel] [PATCH] use MANGLE in flacdsp_mmx

Alexander Strange astrange
Sat Jun 28 08:04:29 CEST 2008

On Jun 28, 2008, at 1:53 AM, Mike Melanson wrote:

> Alexander Strange wrote:
>> This is needed to fix compilation with gcc 4.2 on OS X. make test  
>> passes.
> I'm confused-- I don't work with Mac OS X often but was working with  
> it
> a bit tonight. It has gcc 4.0.1, build 5470 and I have no problem
> compiling FFmpeg. It passes 'make test' and the whole FATE suite. FLAC
> shows up in "ffmpeg -formats".

Yeah, it only happens with the 4.2 builds in the iPhone SDK. Earlier  
versions are fine.

Using "m" to refer to global variables on OS X requires one register  
per variable name, because the compiler refers to all global symbols  
indirectly by default. This saves having to do text relocations or  
load eip, so it's not too bad an idea in general, but it tends to  
break sometimes. But even with that, and considering that non-icc  
compilers are all too stupid to spill the saved stack pointer for the  
VLA[1], I only count six registers used for any one asm. So I don't  
see what's wrong here, but as long as it's fixed it doesn't matter.

[1] I filed a bug about it.

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