"CODE" 35121;
"REAL" "PROCEDURE" ARCSIN(X); "VALUE" X; "REAL" X;
"BEGIN" "REAL" U; U:= ABS(X);
    ARCSIN:= "IF" U<0.8 "THEN" ARCTAN(X/SQRT(1-X*X)) "ELSE"
             SIGN(X) * ( "IF" U=1  "THEN" 1.57079632679489 "ELSE"
             ( 1.57079632679489 - ARCTAN(SQRT(1/(X*X)-1))))
"END" ARCSIN;
        "EOP"