[Ffmpeg-devel] Re: [Ffmpeg-cvslog] r8420 - trunk/libavcodec/dv.c

Guillaume POIRIER poirierg
Sun Mar 25 21:18:09 CEST 2007


Hi,

On 3/25/07, Roman Shaposhnik <rvs at sun.com> wrote:
> On Sun, 2007-03-25 at 15:40 +0300, Uoti Urpala wrote:
> > The de facto ABI on current Linux is 16 byte stack alignment. On OS X
> > the 16 byte alignment requirement has been in the official ABI from the
> > start AFAIK.
>
>   Two things:
>     * that would be just TWO of platforms libavcodec supports.
>     * could you, please, send me a pointer to Mac OSX ABI
>       mandating 16 byte alignment ?

http://developer.apple.com/documentation/DeveloperTools/Conceptual/LowLevelABI/Articles/IA32.html

The function calling conventions used in the IA-32 environment are the
same as those used in the System V IA-32 ABI, with the following
exceptions:

    * Different rules for returning structures
    * The stack is 16-byte aligned at the point of function calls
    * Large data types (larger than 4 bytes) are kept at their natural alignment
    * Most floating-point operations are carried out using the SSE
unit instead of the x87 FPU, except when operating on long double
values. (The IA-32 environment defaults to 64-bit internal precision
for the x87 FPU.)


Guillaume




More information about the ffmpeg-devel mailing list