INT 7F U - Voyetra - AAPISG - API(Application Program[ming] Interface) The defined set of calls which a program may make to interact with or request services of the operating system or environment under which it is running.  Because the inputs and outputs of the calls are well-defined, a program using the API can continue using the identical calls even if the internal organization of the program providing the API changes.
	AX = 4150h ('AP')
	BH = C1h
	BL = function (00h-13h)
	    00h initialize (fails except first time called)
	???
Return: AX = status???
	    0000h successful
	    0001h failed
Program: AAPISG is a driver by Voyetra for the Aztech Sound Galaxy sound board
BUG:	the function range check uses JL instead of JB, so it will cause a
	  crash if BL >= 80h on entry
SeeAlso: AX=4331h,AX=564Dh,AX=5658h