[FFmpeg-cvslog] r24926 - trunk/libavcodec/x86/vp56dsp.asm

[Måns Rullgård]

Reimar D?ffinger <Reimar.Doeffinger at gmx.de> writes:

> On Thu, Aug 26, 2010 at 03:25:52PM -0400, Ronald S. Bultje wrote:
>> On Thu, Aug 26, 2010 at 3:10 PM, Reimar D?ffinger
>> <Reimar.Doeffinger at gmx.de> wrote:
>> > I complained about the name back then already, but x86_reg is designed
>> > to and can be used just fine on all architectures, there really
>> > is no need to reinvent the wheel.
>> > If the term "x86" alone makes you run away screaming then the
>> > solution is to rename it and move it out of x86_cpu.h, but
>> > you certainly don't need to reinvent it!
>> 
>> Got it, the name confused me. I'm OK with it then, if Mans is OK also
>> (even though the problem is limited to x86 only, apparently).
>
> This specific problem? Yes.
> The problem in general? Not so sure.
> Nowadays compilers tend to be brighter, but one of the issues tended to be that
> something like
> int i;
> for (i = 0; i < j; i++)
>    array[i];
> ended up with a sign-extension inside the loop.
> I'd think that is not that unlikely to apply to other 64 bit 
> architectures as well and would make a "register-size" type
> useful for them as well.

That problem is also specific to x86.  I know of no other architecture
where the declared type of the counter would make a difference in a
construct like that.

-- 
M?ns Rullg?rd
mans at mansr.com