CODE (key)
    A 0x01 LDrn, ( @KEY )
    0x28 RSTn,
    L A LDrr, H 0 LDrn,
    HL PUSHqq,
;CODE
CODE (emit)
    BC POPqq, ( c == @DSP arg )
    chkPS,
    A 0x02 LDrn, ( @DSP )
    0x28 RSTn,
;CODE
CODE BYE
    HL 0 LDddnn,
    A 0x16 LDrn, ( @EXIT )
    0x28 RSTn,
