[Pixman] [PATCH 0/2] 7-bit bilinear interpolation precision

Søren Sandmann sandmann at cs.au.dk
Tue Jun 26 08:04:05 PDT 2012

Siarhei Siamashka <siarhei.siamashka at gmail.com> writes:

> Also 7-bit bilinear interpolation precision still allows a nice SSSE3
> optimization, which can be implemented later to get even more speed.

Presumably you mean pmaddubsw, but isn't it a problem that the weights
can go from 0 to 128 inclusive? That is, if one weight is 0, the other
is 128, which means it doesn't actually fit in seven bits. So unless I
am missing something, pmaddubsw can't be used without a test for 0.

> But the patches need a lot more testing on different hardware.

Running the test suite on ppc64, ARM, x86-64 with various
implementations disabled revealed no problems for me.


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