INT D4 - PC-MOS/386 v3.0+ - WAIT FOR EVENT                                      
	AH = 07h
	AL = events to monitor (see #04015)
	BX = number of timer ticks until timeout if AL bit 1 set
	CX = bitmap of IRQs to monitor if AL bit 2 set
		(bit 0 = IRQ0 .. bit 15 = IRQ15)
	DX = port to monitor if AL bit 3 set
Return: CF clear if successful
	    AL = type of event which woke up task (see #04015)
	    CX = IRQ(Interrupt ReQuest) A hardware line connected to the interrupt controller chip which signals that a CPU interrupt should be generated. (if any) which awakened task
	    DX = port (if any) which awakened task
	CF set on error
	    AX = error code (see #01680 at INT 21/AH=59h/BX=0000h)
Note:	a device driver may make this call with AL=00h, which indicates that
	  the driver is responsible for setting and clearing the TCBWAIT field
	  in the TCB.  To put task to sleep, set TCBWAIT bits 2-0 to 001; to
	  reawaken it, set bit 1 (leaving other bits unchanged)
SeeAlso: AH=04h,INT 16/AH=00h,INT 38


Bitfields for PC-MOS/386 events to monitor:
Bit(s)	Description	(Table 04015)
 0	keystroke
 1	timeout
 2	IRQ(Interrupt ReQuest) A hardware line connected to the interrupt controller chip which signals that a CPU interrupt should be generated.
 3	port access
 7	return status of user poll routine (other ignored if set)