The Tor Browser / file diff

     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/js/src/tests/ecma_6/Math/fround.js	Wed Dec 31 06:09:35 2014 +0100
     1.3 @@ -0,0 +1,81 @@
     1.4 +/*
     1.5 + * Any copyright is dedicated to the Public Domain.
     1.6 + * http://creativecommons.org/licenses/publicdomain/
     1.7 + */
     1.8 +
     1.9 +// Some tests regarding conversion to Float32
    1.10 +assertEq(Math.fround(), NaN);
    1.11 +
    1.12 +// Special values
    1.13 +assertEq(Math.fround(NaN), NaN);
    1.14 +assertEq(Math.fround(-Infinity), -Infinity);
    1.15 +assertEq(Math.fround(Infinity), Infinity);
    1.16 +assertEq(Math.fround(-0), -0);
    1.17 +assertEq(Math.fround(+0), +0);
    1.18 +
    1.19 +// Polyfill function for Float32 conversion
    1.20 +var toFloat32 = (function() {
    1.21 +    var f32 = new Float32Array(1);
    1.22 +    function f(x) {
    1.23 +        f32[0] = x;
    1.24 +        return f32[0];
    1.25 +    }
    1.26 +    return f;
    1.27 +})();
    1.28 +
    1.29 +// A test on a certain range of numbers, including big numbers, so that
    1.30 +// we get a loss in precision for some of them.
    1.31 +for (var i = 0; i < 64; ++i) {
    1.32 +    var p = Math.pow(2, i) + 1;
    1.33 +    assertEq(Math.fround(p), toFloat32(p));
    1.34 +    assertEq(Math.fround(-p), toFloat32(-p));
    1.35 +}
    1.36 +
    1.37 +/********************************************
    1.38 +/* Tests on maximal Float32 / Double values *
    1.39 +/*******************************************/
    1.40 +function maxValue(exponentWidth, significandWidth) {
    1.41 +    var n = 0;
    1.42 +    var maxExp = Math.pow(2, exponentWidth - 1) - 1;
    1.43 +    for (var i = significandWidth; i >= 0; i--)
    1.44 +        n += Math.pow(2, maxExp - i);
    1.45 +    return n;
    1.46 +}
    1.47 +
    1.48 +var DBL_MAX = maxValue(11, 52);
    1.49 +assertEq(DBL_MAX, Number.MAX_VALUE); // sanity check
    1.50 +
    1.51 +// Finite as a double, too big for a float
    1.52 +assertEq(Math.fround(DBL_MAX), Infinity);
    1.53 +
    1.54 +var FLT_MAX = maxValue(8, 23);
    1.55 +assertEq(Math.fround(FLT_MAX), FLT_MAX);
    1.56 +assertEq(Math.fround(FLT_MAX + Math.pow(2, Math.pow(2, 8 - 1) - 1 - 23 - 2)), FLT_MAX); // round-nearest rounds down to FLT_MAX
    1.57 +assertEq(Math.fround(FLT_MAX + Math.pow(2, Math.pow(2, 8 - 1) - 1 - 23 - 1)), Infinity); // no longer rounds down to FLT_MAX
    1.58 +
    1.59 +/*********************************************************
    1.60 +/******* Tests on denormalizations and roundings *********
    1.61 +/********************************************************/
    1.62 +
    1.63 +function minValue(exponentWidth, significandWidth) {
    1.64 +    return Math.pow(2, -(Math.pow(2, exponentWidth - 1) - 2) - significandWidth);
    1.65 +}
    1.66 +
    1.67 +var DBL_MIN = Math.pow(2, -1074);
    1.68 +assertEq(DBL_MIN, Number.MIN_VALUE); // sanity check
    1.69 +
    1.70 +// Too small for a float
    1.71 +assertEq(Math.fround(DBL_MIN), 0);
    1.72 +
    1.73 +var FLT_MIN = minValue(8, 23);
    1.74 +assertEq(Math.fround(FLT_MIN), FLT_MIN);
    1.75 +
    1.76 +assertEq(Math.fround(FLT_MIN / 2), 0); // halfway, round-nearest rounds down to 0 (even)
    1.77 +assertEq(Math.fround(FLT_MIN / 2 + Math.pow(2, -202)), FLT_MIN); // first double > FLT_MIN / 2, rounds up to FLT_MIN
    1.78 +
    1.79 +assertEq(Math.fround(-FLT_MIN), -FLT_MIN);
    1.80 +
    1.81 +assertEq(Math.fround(-FLT_MIN / 2), -0); // halfway, round-nearest rounds up to -0 (even)
    1.82 +assertEq(Math.fround(-FLT_MIN / 2 - Math.pow(2, -202)), -FLT_MIN); // first double < -FLT_MIN / 2, rounds down to -FLT_MIN
    1.83 +
    1.84 +reportCompare(0, 0, "ok");