Experimental parser: merge r19949

test/mjsunit/harmony/math-fround.js

-// Copyright 2014 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// Flags: --harmony-maths
-
-// Monkey-patch Float32Array.
-Float32Array = function(x) { this[0] = 0; };
-
-assertTrue(isNaN(Math.fround(NaN)));
-assertTrue(isNaN(Math.fround(function() {})));
-assertTrue(isNaN(Math.fround({ toString: function() { return NaN; } })));
-assertTrue(isNaN(Math.fround({ valueOf: function() { return "abc"; } })));
-assertEquals("Infinity", String(1/Math.fround(0)));
-assertEquals("-Infinity", String(1/Math.fround(-0)));
-assertEquals("Infinity", String(Math.fround(Infinity)));
-assertEquals("-Infinity", String(Math.fround(-Infinity)));
-
-assertEquals("Infinity", String(Math.fround(1E200)));
-assertEquals("-Infinity", String(Math.fround(-1E200)));
-assertEquals("Infinity", String(1/Math.fround(1E-300)));
-assertEquals("-Infinity", String(1/Math.fround(-1E-300)));
-
-mantissa_23_shift = Math.pow(2, -23);
-mantissa_29_shift = Math.pow(2, -23-29);
-
-// Javascript implementation of IEEE 754 to test double to single conversion.
-function ieee754float(sign_bit,
-                      exponent_bits,
-                      mantissa_23_bits,
-                      mantissa_29_bits) {
-  this.sign_bit = sign_bit & 1;
-  this.exponent_bits = exponent_bits & ((1 << 11) - 1);
-  this.mantissa_23_bits = mantissa_23_bits & ((1 << 23) - 1);
-  this.mantissa_29_bits = mantissa_29_bits & ((1 << 29) - 1);
-}
-
-ieee754float.prototype.returnSpecial = function() {
-  if (mantissa_23_bits == 0 && mantissa_29_bits == 0) return sign * Infinity;
-  return NaN;
-}
-
-ieee754float.prototype.toDouble = function() {
-  var sign = this.sign_bit ? -1 : 1;
-  var exponent = this.exponent_bits - 1023;
-  if (exponent == -1023) returnSpecial();
-  var mantissa = 1 + this.mantissa_23_bits * mantissa_23_shift +
-                     this.mantissa_29_bits * mantissa_29_shift;
-  return sign * Math.pow(2, exponent) * mantissa;
-}
-
-ieee754float.prototype.toSingle = function() {
-  var sign = this.sign_bit ? -1 : 1;
-  var exponent = this.exponent_bits - 1023;
-  if (exponent == -1023) returnSpecial();
-  if (exponent > 127) return sign * Infinity;
-  if (exponent < -126) return this.toSingleSubnormal(sign, exponent);
-  var round = this.mantissa_29_bits >> 28;
-  var mantissa = 1 + (this.mantissa_23_bits + round) * mantissa_23_shift;
-  return sign * Math.pow(2, exponent) * mantissa;
-}
-
-ieee754float.prototype.toSingleSubnormal = function(sign, exponent) {
-  var shift = -126 - exponent;
-  if (shift > 24) return sign * 0;
-  var round_mask = 1 << (shift - 1);
-  var mantissa_23_bits = this.mantissa_23_bits + (1 << 23);
-  var round = ((mantissa_23_bits & round_mask) != 0) | 0;
-  if (round) {  // Round to even if tied.
-    var tied_mask = round_mask - 1;
-    var result_last_bit_mask = 1 << shift;
-    var tied = this.mantissa_29_bits == 0 &&
-               (mantissa_23_bits & tied_mask ) == 0;
-    var result_already_even = (mantissa_23_bits & result_last_bit_mask) == 0;
-    if (tied && result_already_even) round = 0;
-  }
-  mantissa_23_bits >>= shift;
-  var mantissa = (mantissa_23_bits + round) * mantissa_23_shift;
-  return sign * Math.pow(2, -126) * mantissa;
-}
-
-
-var pi = new ieee754float(0, 0x400, 0x490fda, 0x14442d18);
-assertEquals(pi.toSingle(), Math.fround(pi.toDouble()));
-
-function fuzz_mantissa(sign, exp, m1inc, m2inc) {
-  for (var m1 = 0; m1 < (1 << 23); m1 += m1inc) {
-    for (var m2 = 0; m2 < (1 << 29); m2 += m2inc) {
-      var float = new ieee754float(sign, exp, m1, m2);
-      assertEquals(float.toSingle(), Math.fround(float.toDouble()));
-    }
-  }
-}
-
-for (var sign = 0; sign < 2; sign++) {
-  for (var exp = 1024 - 170; exp < 1024 + 170; exp++) {
-    fuzz_mantissa(sign, exp, 1337 * exp - sign, 127913 * exp - sign);
-  }
-}