[FFmpeg-devel] [PATCH] Remove MULL macro from lsp.c

[Michael Niedermayer]

On Sat, Aug 23, 2008 at 01:08:13AM +0700, Vladimir Voroshilov wrote:
> Attached patch replaces MULL macro in lsp.c with multiplication and right shift.
> Current code works wrong because one of macro's arguments is int16_t while asm
> assumes both of them to be int.
> 
> I'll also remove all occurences of MULL macro from my G.729 code.
> 
> P.S. Another fix is leaving MULL there but explicitly cast the second
> argument to (int).
> I don't know which is better.

I would say that the bug you are trying to fix is in MULL
it should work when its arguments are not int.

besides

[...]
>          f[i] = f[i-2];
>          for(j=i; j>1; j--)
> -            f[j] -= MULL(f[j-1], lsp[2*i-2]) - f[j-2]; // (3.22) * (0.15) * 2 -> (3.22)
> +            f[j] -= (((int64_t)f[j-1] * lsp[2*i-2]) >> 14) - f[j-2]; // (3.22) * (0.15) * 2 -> (3.22)
>  

please fix the comments

also please fix the comments in ff_acelp_high_pass_filter()
they contradict the claim that cliping is needed. One of them has to
be wrong.

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

it is not once nor twice but times without number that the same ideas make
their appearance in the world. -- Aristotle
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