MAIN START
    LAD GR1,=10
    LAD GR2,=20
    LD GR1,0,GR1
    LD GR2,0,GR2
    ST GR1,A
    LD GR3,A
    ST GR2,B
    LD GR3,A
    RET
A DS 0
B DS 1
    END