Obtains the current value of the pixel on the display at the specified graphics coordinates.
Call with:
AH = 0DH
BH = page
CX = column (graphics x coordinate)
DX = row (graphics y coordinate)
Returns:
AL = pixel value
Notes:
The range of valid (x,y) coordinates and possible pixel values depends on the current video mode.
Register BH is ignored for display modes that support only one page.