(entry) ~ACIA ( Set RST 38 jump ) PC ORG @ 0x39 + !
    AF PUSH, HL PUSH, DE PUSH,
	( Read our character from ACIA into our BUFIDX )
    ACIA_CTL INAi,
    0x01 ANDi,   ( is ACIA rcv buf full? )
    IFNZ,
        ( correct interrupt cause )
        ACIAW> LDHL(n),
        ( is it == to ACIAR>? )
        ( +0 == ACIAR> )
        DE ACIAR> LDdd(n),
        ( carry cleared from ANDi above )
        DE SBCHLd,                                    ( cont. )