c $BBCC waits for a key and sets SEED based on how long the routine runs for while a key *IS* pressed
C $BBCC preserve HL, DE, BC
C $BBCF jump to $BBE3 if current player is not human (i.e. quit routine)
C $BBD5 preserve BC
C $BBD6 call KEY-SCAN in ROM
C $BBD9 restore BC
C $BBDA increment counter (used to set SEED later)
C $BBDB loop back to $BBD5 if a key was pressed
C $BBDF key was released, so set SEED to the value of the counter
C $BBE3 restore BC, DE, HL
C $BBE6 return to caller