On Mon, 1 Jan 2024, Paolo Bonzini wrote:
Il dom 31 dic 2023, 17:27 BALATON Zoltan <bala...@eik.bme.hu> ha scritto:
palette = vga->last_palette;
hpel = (hpel >> 1) & 3;
+
+ /* For 256 color modes, we can adjust the source address and write
directly
+ * to the destination, even if horizontal pel panning is active.
However,
+ * the loop below assumes that the address does not wrap in the
middle of a
+ * plane. If that happens...
+ */
+ if (addr + (width >> 3) * 4 < VGA_VRAM_SIZE) {
+ addr += hpel * 4;
+ hpel = 0;
+ }
+
+ /* ... use the panning buffer as in planar modes. */
if (hpel) {
width += 8;
d = vga->panning_buf;
Is it possible to do these checks once in vga.c and instead of changing
the return value of the draw functions pass panning_buf as d if needed?
Maybe that way the draw funcs could be left unchanged?
As of the previous patch it could, here however the logic for whether to
use the panning_buf depends on the drawing function; 8d2 is special and
different from the others.
I can remove the optimization, it's not super Important; but it's kind of
obvious to do it for the VGA 256-color modes, since they're the only ones
with the same bit alignment for all pixels.
I guess that means it's not easy to do so my question is not so imprtant
then.
Regards,
BALATON Zoltan
