[XviD-devel] sse2

[daniel smith]

> all code was written by Dmitry Rozhdestvensky dmitry@servertd.spb.ru
> except the quant sse and cpb sse functions that
> were written by daniel. Dmitry rewrote the sse2 sad code because he
> told me that dan's code assumed correct alignment
> and that this won't work in reality. I have no p4 box, so I have to
> trust him...

i'd have to check the code again, however from memory it only assumed alignment for the pointer which is from the current "fixed" block, i.e. always at a 16x16 position.  it assumed unalignment for the "floating" block, i.e. which could be at any (x,y) position from the reference frame.  i never got a privileged instruction crash out of it after several hours testing.. perhaps pete can verify?

> I don't have a p4, but Vladimir, who tested the current sse2 code,
> sent me a profiling log and it seems that the quant
> sse2 functions don't give much improvement, the dequant sse2
> functions seem to be even slower than the mmx'ed ones...

all i remember doing for those is changing registers / loop counts to suit the sse2 registers.  wouldn't be surprised if they turned out slower (they ran dead even on my work computer).

dan
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