INT 10 - VIDEO - READ LIGHT PEN POSITION (except VGAVideo Graphics Array(Video Graphics Array) The video adapter introduced with the IBMInternational Busiuness Machines PS/2IBM PS/2, any model series of computers.)
AH = 04h
Return: AH = light pen trigger flag
00h not down/triggered
01h down/triggered
DH,DL = row,column of character light pen is on
CH = pixel row (graphics modes 04h-06h)
CX = pixel row (graphics modes with >200 rows)
BX = pixel column
Desc: determine the current position and status of the light pen (if
present)
Notes: on a CGAColor Graphics Adapter(Color/Graphics Adapter) One of the two video display boards introduced together with the original IBMInternational Busiuness Machines PCIBM PC. See also HGC, MDA., returned column numbers are always multiples of 2 (320-
column modes) or 4 (640-column modes)
returned row numbers are only accurate to two lines