Category: BIOS

INT 15 - BIOS - JOYSTICK SUPPORT (XT after 1982/11/8,AT,XT286,PS)

	AH = 84h
	DX = subfunction
	    0000h read joystick switches
		Return: AL bits 7-4 = switch settings
	    0001h read positions of joysticks
		Return: AX = X position of joystick A
			BX = Y position of joystick A
			CX = X position of joystick B
			DX = Y position of joystick B
Return: CF set on error
	    AH = status (see #00496)
	CF clear if successful
Notes:	if no game port is installed, subfunction 0000h returns AL=00h (all
	  switches open) and subfunction 0001h returns AX=BX=CX=DX=0000h
	a 250kOhm joystick typically returns 0000h-01A0h
SeeAlso: AH=84h"V20-XT-BIOS"