DCL SPCPTR .PARM1 PARM;
DCL DD PARM1 CHAR(5) BAS(.PARM1);
    DCL DD PARM-NBR-ELEMENTS PKD(7,0) DEF(PARM1) POS(1);
    DCL DD PARM-DIRECTION    CHAR(1)  DEF(PARM1) POS(5); /* A OR D */

DCL SPCPTR .PARM2 PARM;
DCL DD ELEMENT(1) CHAR(10) BAS(.PARM2);
DCL DD KEY    (1) CHAR(10) BAS(.PARM2);

DCL OL PARMS(.PARM1, .PARM2) EXT PARM MIN(2);

DCL DD SWAP-FLAG  CHAR(1);
DCL DD JUMP-SIZE   BIN(4);
DCL DD SWEEP-END   BIN(4);
DCL DD ITEM-NBR    BIN(4);
DCL DD COMP-NBR    BIN(4);

ENTRY * (PARMS) EXT;
    OVRPGATR   1, 2; /* DON'T CONSTRAIN ARRAY REFS */
    CPYNV      JUMP-SIZE, PARM-NBR-ELEMENTS;
SORT-JUMP:
    CMPNV(B)   JUMP-SIZE,  1 /HI(SORT-SWEEP);
    CMPBLA(B)  SWAP-FLAG, "S"/NEQ(RETURN);
SORT-SWEEP:
    MULT(S)    JUMP-SIZE, 10;
    ADDN(S)    JUMP-SIZE,  3;
    DIV(S)     JUMP-SIZE, 13;
    SUBN       SWEEP-END, PARM-NBR-ELEMENTS, JUMP-SIZE;
    CPYBLA     SWAP-FLAG, " ";
    CPYNV(B)   ITEM-NBR, 0/ZER(SORT-COMPARE);

SORT-SWAP:
    EXCHBY     ELEMENT(ITEM-NBR), ELEMENT(COMP-NBR);
    CPYBLA     SWAP-FLAG, "S";
SORT-COMPARE:
    ADDN(S)    ITEM-NBR, 1;
    CMPNV(B)   ITEM-NBR, SWEEP-END/HI(SORT-JUMP);
    ADDN       COMP-NBR, ITEM-NBR, JUMP-SIZE;
    CMPBLA(B)  PARM-DIRECTION, "D"/EQ(DESCENDING-SORT-COMPARE);

ASCENDING-SORT-COMPARE:
    CMPBLA(B)  KEY(ITEM-NBR), KEY(COMP-NBR)/
               HI(SORT-SWAP), NHI(SORT-COMPARE);
DESCENDING-SORT-COMPARE:
    CMPBLA(B)  KEY(ITEM-NBR), KEY(COMP-NBR)/
               LO(SORT-SWAP), NLO(SORT-COMPARE);

RETURN:
    RTX        *;