[FFmpeg-devel] [PATCH] update doc/optimization.txt

Michael Niedermayer michaelni
Wed Sep 22 15:22:03 CEST 2010

On Wed, Sep 22, 2010 at 02:11:49PM +0100, M?ns Rullg?rd wrote:
> Michael Niedermayer <michaelni at gmx.at> writes:
> > On Wed, Sep 22, 2010 at 08:37:07AM -0400, Ronald S. Bultje wrote:
> >> Also, should I mention (in general tips) that functions that use huge
> >> structs (e.g. MpegEncContext) are A) "discouragable" in general and B)
> >> better written in inline asm than yasm because of the difficulty of
> >> predicting struct offsets?
> >
> > B is ok about A, who uses huge structs when its not needed ...
> If possible, the asm functions should be passed pointers into (or
> values from) the struct in preference over passing a pointer to the
> whole struct.

if one needs just 1 pointer into a struct yes, if one needs 5, its not
efficient to use up 5 registers and waste the time to initialize them
besides that x86-32 has too few registers for this to work out

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In fact, the RIAA has been known to suggest that students drop out
of college or go to community college in order to be able to afford
settlements. -- The RIAA
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