[MPlayer-dev-eng] [PATCH] Make mp3lib SIMD optimizations work on AMD64, Part 5

[Zuxy Meng]

Hi,

2007/5/25, Zuxy Meng <zuxy.meng at gmail.com>:
> Hi,
>
> 2007/5/25, Guillaume Poirier <gpoirier at mplayerhq.hu>:
> > Hi,
> >
> > Reimar Döffinger wrote:
> > > Hello,
> > > On Fri, May 25, 2007 at 02:14:49PM +0800, Zuxy Meng wrote:
> > >>  We've reached Part 5. This is again a big diff, replacing many 'long'
> > >>  to 'int', and several 'real' to 'short'. Among those, many are
> > >>  necessary because under LP64 environment, sizeof(long) != sizeof(int)
> > >>  and sizeof(long) != sizeof(float); others are optimizations simply
> > >>  because we really don't need such a long type, or the declaration
> > >>  didn't match its use (declared as float, used as short).
> > >
> > > These are separate issues and should be fixed in different patches. Also
> > > if you changed long to int because the code assumes 32 bits, it would
> > > make more sense to change it to int32_t. Replacing long with int without
> > > thinking can make the code even slower on 64 bit systems.
> >
> > [..]
> >
> > >
> > > This is unrelated and also completely useless since a static function
> > > that is used in only one place will be inlined anyway.
> > > In addition it is wrong since "static void make_decode_tables()" !=
> > > "static void make_decode_tables(void)"
> >
> >
> > Thanks for your quality review Reimar! I realize I'm quite a lousy
> > reviewer, but I'm trying to do my best! :-(
>
> But you're always a prompt tester and more importantly, a nice guy
> who's easy to get along with:-)
>
> Anway I've updated the patch according to suggestions from you and
> Reimar, which should be cleaner.
>
> In this patch, long->int conversions are carried out because any of
> the following:
> 1. Assumed 32-bit access either by inline assembly or by bswap_32
> macros. (e.g. variables in decode_i586.c, costab_mmx in decode_MMX.c
> and newhead in sr1.c)
> 2. Value that never exceed 32 bits. (such as variables representing
> sampling frequency and frame size, variables initialized to known
> 32-bit integers, and variables that are assigned by an 'int' and are
> used to pass an 'int' parameter.

I've tested the patch on IA-32 and AMD64 (thanks to Stefan's testbed!)
and no regression has been found.

-- 
Zuxy
Beauty is truth,
While truth is beauty.
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