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