INT E0 - PCROBOTS v1.41 - "RECEIVE" - GET DATA FROM OTHER ROBOTS

	AX = 0012h
Return: AX = status
	    0000h no data available
	    0001h data retrieved
		BX = sender's ID
		CX = data
Note:	each robot has a 20-word receive FIFO; if the FIFO is full, other
	  robots will be unable to send more data until some is read