47 ms·
A starting point... after which the countless "out_port" incantations begin. All just to get to unchained mode (aka Mode-X) with hardware scrolling & split scr
by vardump 7y ago
A starting point... after which the countless "out_port" incantations begin.
All just to get to unchained mode (aka Mode-X) with hardware scrolling & split screen, 256 kB VRAM, VGA latch fills and VRAM to VRAM latch blitting. It was amazing to be able to set or copy four 256 color pixels by writing just a single byte.
Of course VGA latch blitting didn't make any sense on 486s, but on 8088 it could be almost 4x performance boost — 256 colors with similar CPU load as CGA's 4 colors! At least as long as you needed to blit something to an x-coordinate that's divisible by 4...