[SDL] Alpha blending bug - fixed?

Gabriel Gambetta mystml at adinet.com.uy
Tue Nov 21 13:51:38 PST 2006


Thanks for listening :)

The patch you sent doesn't even compile - 

./src/video/SDL_blit_A.c: In function 'BlitRGBtoRGBPixelAlphaMMX3DNOW':
./src/video/SDL_blit_A.c:1571: error: memory input 1 is not directly
addressable

In any case I guess GCC should be smart enough to make this work as
expected, whether it's an alignment issue or a data size issue. GCC bug
maybe?

	--Gabriel


El mar, 21-11-2006 a las 16:30 -0500, Ryan C. Gordon escribió:
> > The only thing I could find out was that ashift is 32-bit aligned but
> > sf->Ashift isn't:
> 
> I don't think it's an alignment issue, since GCC should be smart enough 
> to get it into a register even if unaligned...however, sf->AShift is 8 
> bits, and ashift is 32, which is probably why you get different 
> results...it probably landed in (say) %al instead of %eax, leaving junk 
> in the rest of the register's bits.
> 
> Try the attached patch and see if it works, too.






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