INT 15H 84H: Joystick Support


 Expects: AH    84H

          DX    subfn code: 0 = read buttons (switches) into AL

                            1 = read joystick positions into AX,BX,CX,DX


 Returns: AH    84H

          AL    (DX=0) bits 4-7 indicate state of joystick buttons

          AX    (DX=1) joystick A horizontal coordinate

          BX           joystick A vertical coordinate

          CX           joystick B horizontal coordinate

          DX           joystick B vertical coordinate

          CF    CY (1) if DX was invalid

                NC (0) no error


    Info: This reads the current buttons or resistive inputs of the

          joystick (or other general analog-to-digital device).

          See Game I/O Adapter Port (201H) for layout of the bits for the

          switches (buttons) and related info.

See Also: INT 15H (extended AT services)

          BIOS Data Area

          ROM-BIOS Functions