INT 10h,  0Dh (13)       Read Pixel

Reports the color of the pixel at a specified screen coordinate.

On entry:      AH         0Dh
CX         Horizontal position of pixel
DX         Vertical position of pixel
BH         Display page number (graphics modes with more
than 1 page)

Returns:       AL         Color of pixel

Registers destroyed:      AX, SP, BP, SI, DI

                                                                          
                             Legal values

  Mode   CX (Horizontal)  DX (Vertical)   AL (Pixel Color)    BH (Page Number)
04h      0-319            0-199             0-3
05h       0-319            0-199             0-3
06h       0-639            0-199             0-1
0Dh       0-319            0-199             0-15                  0-7
0Eh       0-639            0-199             0-15                  0-3
0Fh       0-639            0-349             0-1                   0-1
10h       0-639            0-349             0-15                  0-1
                                                                          

Notes:         For modes 0Dh through 10h, a page number needs to be
supplied in BH.

See also: INT 10h, 0Ch

INT 10h, 0Dh (13) Read Pixel