> x = curent_destination_byte;
> z = x & 00000111b
> x = z | y
> You have to do this to do every single pixel write with 15bit color. With
> 16bit color all the bytes are even so it's just
> dest = val;
No. Depth 15 is stored in the framebuffer at 16 bpp; i.e. there's one
pixel per 16 bits, with one bit wasted.
There is an issue similar to the one you describe at depth 24/24 bpp
(as opposed to depth 24/32 bpp) where a single pixel write has to be
split into one byte and one halfword writes.
(In XFree86 4; XFree86 3 would do three single-byte writes.)
Juliusz