)
Call IPXODI GNMA entry point with:
	BX = function
	    0000h Register Responder
		ES:SI -> responder structure (see #02899)
		Return: CF clear if successful
			CF set on error
			AX = status
			    FFFFh if specified responder is already registered
			interrupts enabled
			all other registers except DS, CS:IP, SS:SP destroyed
		Note:	the responder structure must not be deallocated until
			  the responder is deregistered
	    0001h Deregister Responder
		AX = type of responder to deregister
		Return: AX = status
			    FFFFh if specified responder not registered
			interrupts enabled
			ES:SI buffer from original registration may now be
			      freed
			all other registers except DS, CS:IP, SS:SP destroyed
	    0002h Get Responders
		Return: ES:SI -> head of responder structure list (read-only)
			interrupts enabled
			all other registers except DS, CS:IP, SS:SP destroyed
		Note:	the returned list may change as tasks are swapped in
			  and out
	    0003h Send Acknowledgement
		AL = completion code
		    00h successful
		    01h-FCh responder-specific
		    FDh invalid function
		CX = length of return data (0000h if none)
		DX:SI -> return data
		Return: interrupts enabled
			all other registers except DS, CS:IP, SS:SP destroyed