Routine:        Wait    
Function:       Waits for a keypress
Called by:      Error, Main, Pb2
Calls:          Keyb
Entry:          None
Exit:           A holds keycode
Preserved:      E, IX, IY


WAIT    CALL    KEYB
; Scan keyboard, and loop if no key was pressed.
        CP      255
        JR      Z,WAIT
        RET