1// Copyright 2014 the V8 project authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5// Flags: --allow-natives-syntax
6
7// Monkey-patch Float32Array.
8Float32Array = function(x) { this[0] = 0; };
9
10assertTrue(isNaN(Math.fround(NaN)));
11assertTrue(isNaN(Math.fround(function() {})));
12assertTrue(isNaN(Math.fround({ toString: function() { return NaN; } })));
13assertTrue(isNaN(Math.fround({ valueOf: function() { return "abc"; } })));
14assertTrue(isNaN(Math.fround(NaN)));
15assertTrue(isNaN(Math.fround(function() {})));
16assertTrue(isNaN(Math.fround({ toString: function() { return NaN; } })));
17assertTrue(isNaN(Math.fround({ valueOf: function() { return "abc"; } })));
18
19function unopt(x) { return Math.fround(x); }
20function opt(y) { return Math.fround(y); }
21
22opt(0.1);
23opt(0.1);
24unopt(0.1);
25%NeverOptimizeFunction(unopt);
26%OptimizeFunctionOnNextCall(opt);
27
28function test(f) {
29  assertEquals("Infinity", String(1/f(0)));
30  assertEquals("-Infinity", String(1/f(-0)));
31  assertEquals("Infinity", String(f(Infinity)));
32  assertEquals("-Infinity", String(f(-Infinity)));
33  assertEquals("Infinity", String(f(1E200)));
34  assertEquals("-Infinity", String(f(-1E200)));
35  assertEquals("Infinity", String(1/f(1E-300)));
36  assertEquals("-Infinity", String(1/f(-1E-300)));
37}
38
39test(opt);
40test(unopt);
41
42mantissa_23_shift = Math.pow(2, -23);
43mantissa_29_shift = Math.pow(2, -23-29);
44
45// Javascript implementation of IEEE 754 to test double to single conversion.
46function ieee754float(sign_bit,
47                      exponent_bits,
48                      mantissa_23_bits,
49                      mantissa_29_bits) {
50  this.sign_bit = sign_bit & 1;
51  this.exponent_bits = exponent_bits & ((1 << 11) - 1);
52  this.mantissa_23_bits = mantissa_23_bits & ((1 << 23) - 1);
53  this.mantissa_29_bits = mantissa_29_bits & ((1 << 29) - 1);
54}
55
56ieee754float.prototype.returnSpecial = function() {
57  if (mantissa_23_bits == 0 && mantissa_29_bits == 0) return sign * Infinity;
58  return NaN;
59}
60
61ieee754float.prototype.toDouble = function() {
62  var sign = this.sign_bit ? -1 : 1;
63  var exponent = this.exponent_bits - 1023;
64  if (exponent == -1023) returnSpecial();
65  var mantissa = 1 + this.mantissa_23_bits * mantissa_23_shift +
66                     this.mantissa_29_bits * mantissa_29_shift;
67  return sign * Math.pow(2, exponent) * mantissa;
68}
69
70ieee754float.prototype.toSingle = function() {
71  var sign = this.sign_bit ? -1 : 1;
72  var exponent = this.exponent_bits - 1023;
73  if (exponent == -1023) returnSpecial();
74  if (exponent > 127) return sign * Infinity;
75  if (exponent < -126) return this.toSingleSubnormal(sign, exponent);
76  var round = this.mantissa_29_bits >> 28;
77  var mantissa = 1 + (this.mantissa_23_bits + round) * mantissa_23_shift;
78  return sign * Math.pow(2, exponent) * mantissa;
79}
80
81ieee754float.prototype.toSingleSubnormal = function(sign, exponent) {
82  var shift = -126 - exponent;
83  if (shift > 24) return sign * 0;
84  var round_mask = 1 << (shift - 1);
85  var mantissa_23_bits = this.mantissa_23_bits + (1 << 23);
86  var round = ((mantissa_23_bits & round_mask) != 0) | 0;
87  if (round) {  // Round to even if tied.
88    var tied_mask = round_mask - 1;
89    var result_last_bit_mask = 1 << shift;
90    var tied = this.mantissa_29_bits == 0 &&
91               (mantissa_23_bits & tied_mask ) == 0;
92    var result_already_even = (mantissa_23_bits & result_last_bit_mask) == 0;
93    if (tied && result_already_even) round = 0;
94  }
95  mantissa_23_bits >>= shift;
96  var mantissa = (mantissa_23_bits + round) * mantissa_23_shift;
97  return sign * Math.pow(2, -126) * mantissa;
98}
99
100
101var pi = new ieee754float(0, 0x400, 0x490fda, 0x14442d18);
102assertEquals(pi.toSingle(), opt(pi.toDouble()));
103assertEquals(pi.toSingle(), unopt(pi.toDouble()));
104
105
106function fuzz_mantissa(sign, exp, m1inc, m2inc) {
107  for (var m1 = 0; m1 < (1 << 23); m1 += m1inc) {
108    for (var m2 = 0; m2 < (1 << 29); m2 += m2inc) {
109      var float = new ieee754float(sign, exp, m1, m2);
110      assertEquals(float.toSingle(), unopt(float.toDouble()));
111      assertEquals(float.toSingle(), opt(float.toDouble()));
112    }
113  }
114}
115
116for (var sign = 0; sign < 2; sign++) {
117  for (var exp = 1024 - 170; exp < 1024 + 170; exp++) {
118    fuzz_mantissa(sign, exp, 1337 * exp - sign, 127913 * exp - sign);
119  }
120}
121