collapseos/blk/353

(entry) ~ACIA
    AF PUSHqq,
    HL PUSHqq,
    DE PUSHqq,
	( Read our character from ACIA into our BUFIDX )
    ACIA_CTL INAn,
    0x01 ANDn,   ( is ACIA rcv buf full? )
    IFNZ,
        ( correct interrupt cause )
        ( +2 == ACIAW> )
        ACIA_MEM 2+ LDHL(nn),
        ( is it == to ACIAR>? )
        ( +0 == ACIAR> )
        DE ACIA_MEM LDdd(nn),
        ( carry cleared from ANDn above )
        DE SBCHLss,                                   ( cont. )