INT 10,C - Write Graphics Pixel at Coordinate

AH = 0C

AL = color value (XOR'ED with current pixel if bit 7=1)

BH = page number, see ~VIDEO PAGES~

CX = column number (zero based)

DX = row number (zero based)

returns nothing

- if bit 7 is 1, color specified is XOR'ed with current pixel

- page number in BH ignored for 320x200 4 color graphics mode

- this function is known to destroy AX and possibly SI and DI on

on some PS/2 VGA systems