Siarhei Siamashka <[email protected]> writes:
> The 'test1' function does not look good because it uses ARM
> instructions to read data one byte at a time and combine it. Function
> 'test2' looks a bit better because it now uses WALIGNR, but this is
> still not an optimal solution. Ideally, if we need to read N
> contiguous unaligned 64-bit values, this requires (N + 1) loads via
> WLDRD instructions and N fixups via WALIGNR, also shift argument for
> WALIGNR has to be calculated only once.
Yes, this would be the best way. It should be possible to do something
like this for acessing 32 bit values:
while (height--)
{
...
align = 4 - (src & 3);
st = wldrd (src & ~3)
src += 4;
while (w >= 4)
{
new_st = wldr (src);
s = walignr (st, new_st, align);
st = new_st;
...
}
If the wldr/walignr instructions are encapsulated in inline functions,
then for x86 those functions could simply expand to movd/movq.
Soren
_______________________________________________
Pixman mailing list
[email protected]
http://lists.freedesktop.org/mailman/listinfo/pixman
