: XYPOS [ VDP_MEM LITN ] ;
CODE _ctl ( a -- sends LSB then MSB )
    HL POPqq, chkPS,
    A L LDrr, VDP_CTLPORT OUTnA,
    A H LDrr, VDP_CTLPORT OUTnA,
;CODE
CODE _data
    HL POPqq, chkPS,
    A L LDrr, VDP_DATAPORT OUTnA,
;CODE