code 41571;
real procedure EXTVAL(X, LOC, SCALE);
value X, LOC, SCALE; real X, LOC, SCALE;
begin
    if SCALE ≤ 0 then
        STATAL3 ERROR(“EXTVAL”, 3, SCALE);
    X:= -(X - LOC) / SCALE;
    EXTVAL:= if X > LN(-LN(MINREAL))
                    then 0
                    else EXP(-EXP(X));
end EXTVAL;
eop