* PSET seems to use an internal x and y coordinate.
* The internal x and y coordinates are validated before use by masking them. When width is 256 then mask is 0x0ff, when 512 the mask is 0x01ff, when 1024 the mask is 0x03ff and when 2048 the mask is 0x07ff. Therefore attempting to write to x=300 on a 256 width screen actually writes to pixel x=0x02cbecause it is masked before use.
* During testing I found that the 'advance' part of the PSET command differs slightly from the official document.