lblexec BSET ( DI -> wordref )
    AL [DI] MOVr[], DI INCx, ( PFA )
    AL AL ORrr, IFZ, DI JMPr, THEN, ( native )
    AL DECr, IFNZ, ( not compiled )
        AL DECr, IFZ, ( cell )
            DI PUSHx, JMPs, lblnext @ RPCs, THEN,
        AL DECr, IFZ, ( does )
            DI PUSHx, DI INCx, DI INCx, DI [DI] MOVx[], THEN,
        ( alias or switch ) DI [DI] MOVx[],
        AL DECr, IFNZ, ( switch ) DI [DI] MOVx[], THEN,
        JMPs, lblexec @ RPCs,
    THEN, ( continue to compiled )
    BP INCx, BP INCx, [BP] 0 DX MOV[]+x, ( pushRS )
    DX DI MOVxx, DX INCx, DX INCx, ( --> IP )
    DI [DI] MOVx[], JMPs, lblexec @ RPCs,