100H:

/* DAMM CHECKSUM FOR DECIMAL NUMBER IN GIVEN STRING */
CHECK$DAMM: PROCEDURE (PTR) BYTE;
    DECLARE PTR ADDRESS, CH BASED PTR BYTE;
    DECLARE DAMM DATA
        ( 0,3,1,7,5,9,8,6,4,2,
          7,0,9,2,1,5,4,8,6,3,
          4,2,0,6,8,7,1,3,5,9,
          1,7,5,0,9,8,3,4,2,6,
          6,1,2,3,0,4,5,9,7,8,
          3,6,7,4,2,0,9,5,8,1,
          5,8,6,9,7,2,0,1,3,4,
          8,9,4,5,3,6,2,0,1,7,
          9,4,3,8,6,1,7,2,0,5,
          2,5,8,1,4,3,6,7,9,0 );
    DECLARE I BYTE;
    I = 0;
    DO WHILE CH <> '$';
        I = DAMM((I*10) + (CH-'0'));
        PTR = PTR + 1;
    END;
    RETURN I = 0;
END CHECK$DAMM;

/* CP/M BDOS CALLS */
BDOS: PROCEDURE (FN, ARG);
    DECLARE FN BYTE, ARG ADDRESS;
    GO TO 5;
END BDOS;

PRINT: PROCEDURE (STR);
    DECLARE STR ADDRESS;
    CALL BDOS(9, STR);
END PRINT;

/* TESTS */
DECLARE TEST (4) ADDRESS;
TEST(0) = .'5724$';
TEST(1) = .'5727$';
TEST(2) = .'112946$';
TEST(3) = .'112949$';

DECLARE N BYTE;
DO N = 0 TO LAST(TEST);
    CALL PRINT(TEST(N));
    CALL PRINT(.': $');
    IF CHECK$DAMM(TEST(N)) THEN
        CALL PRINT(.'PASS$');
    ELSE
        CALL PRINT(.'FAIL$');
    CALL PRINT(.(13,10,'$'));
END;

CALL BDOS(0,0);
EOF