INT 2D - AMIS v3.0+ - DETERMINE CHAINED INTERRUPTS

	AL = 04h
	AH = multiplex number for program
	BL = interrupt number (except 2Dh)
Return: AL = status
	    00h not implemented (makes TSR non-compliant with specification)
	    01h (obsolete) unable to determine
	    02h (obsolete) interrupt hooked
	    03h (obsolete) interrupt hooked, address returned
		DX:BX -> TSR's interrupt BL handler
	    04h list of hooked interrupts returned
		DX:BX -> interrupt hook list (see #02571)
	    FFh interrupt not hooked
Notes:	BL is ignored if the TSR returns AL=04h; in that case, the caller
	  needs to scan the return list rather than making additional calls
	  to this function.  If the return is not 00h or 04h, then the caller
	  must cycle through the remaining interrupt numbers it wishes to
	  check.
	return values 01h through 03h may not be used by AMIS v3.6-compliant
	  programs; they are included here solely for compatibility with
	  version 3.3, though they were probably never used in any
	  implementation
	for return values 01h through 03h, since INT 2D is known to be hooked,
	  the resident code need not test for BL=2Dh (to minimize its size),
	  and the return value is therefore undefined in that case.
	this function is not valid unless a program is installed on the
	  specified multiplex number; use INT 2D/AL=00h to check
SeeAlso: INT 2D/AL=00h,INT 2D/AL=01h,INT 2D/AL=02h,INT 2D/AL=03h,INT 2D/AL=05h
SeeAlso: INT 2D/AL=06h