DCL DD N    FLT(8);
DCL DD SQRT FLT(8);

DCL DD P  FLT(8);
DCL DD Y  FLT(8);
DCL DD A  FLT(8);
DCL DD B  FLT(8);
DCL DD C  FLT(8);

    CPYNV        P, 4;
    CPYNV        N, 2;
    CMF1         SQRT, X'0020', N;

    SUBN         Y, SQRT, 1;
    MULT         B, SQRT, 4;
    SUBN         A, 6, B;

    CPYNV        M, 3;
:   CALLI        ITERATE-PI, *, .ITERATE-PI;
    SUBN(SB)     M, 1/HI(=-1);

    RTX          *;

DCL DD M  BIN(2);
DCL DD PI FLT(8);
DCL INSPTR .ITERATE-PI;
ENTRY       ITERATE-PI INT;
    MULT         B, Y, Y;
    MULT(S)      B, B;
    SUBN         N, 1, B;
    CMF1         SQRT, X'0020', N;
    CMF1         B,    X'0020', SQRT;

    SUBN         Y, 1, B;
    ADDN         C, 1, B;
    DIV(S)       Y, C;

    ADDN         B, 1, Y;
    MULT         C, Y, Y;
    ADDN(S)      C, B;
    MULT(S)      C, Y;
    MULT(S)      C, P;

    MULT(S)      P, 4;
    MULT(S)      B, B;
    MULT(S)      B, B;
    MULT(S)      A, B;

    SUBN(S)      A, C;
    SUBN(S)      A, C;

    DIV          PI, 1, A;
    CPYNV        QQ, PI;
    CPYBLAP      MSG-TEXT, QQ, " ";
    CALLI        SHOW-MESSAGE, *, .SHOW-MESSAGE;
    B           .ITERATE-PI;

DCL DD QQ ZND(31,30);
%INCLUDE SHOWMSG