[FFmpeg-devel] [PATCH] Do not assume long is same width as x86 register in swscale.

Måns Rullgård mans
Tue Jan 27 22:05:08 CET 2009

Reimar D?ffinger <Reimar.Doeffinger at stud.uni-karlsruhe.de> writes:

> On Tue, Jan 27, 2009 at 08:36:32PM +0000, M?ns Rullg?rd wrote:
>> Reimar D?ffinger <Reimar.Doeffinger at stud.uni-karlsruhe.de> writes:
>> > I think x,w,h are "long" for speed reasons, so they should be x86_reg,
>> > too...
>> int_fast32_t for the fastest type at least 32 bits wide.
> No, that is wrong. int_fast32_t == int32_t would be best for
> calculations etc., but as soon as it is used for indexed
> addressing int_fast32_t == int64_t would be best.

You'll probably find that it is 32 or 64 bits on most modern machines.

> The idea of a int_fast32_t type is plain broken for anything but RISC.

On any of the 36-bit machines, most of them very much non-RISC, it
makes sense for int_fast32_t to be 36 bits wide whatever the purpose.

M?ns Rullg?rd
mans at mansr.com

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