Sinclair QL - Displaying Bitmaps & Text

Direct video memory

Video memory starts at 0x20000

In Mode 4 (512×256 4 colour) the memory is laid out in byte pairs (or words)

Red byte | Green byte 7 6 5 4 3 2 1 0 | 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 | 0 0 0 0 0 0 0 0

Those 16 bits set a series of 8 pixels. The values of the Red and Green byte are AND-ed to get the final colour:

Red | Green | Result 1 | 0 | Red 0 | 1 | Green 1 | 1 | White 0 | 0 | Black