1// Copyright 2013 the V8 project authors. All rights reserved. 2// Redistribution and use in source and binary forms, with or without 3// modification, are permitted provided that the following conditions are 4// met: 5// 6// * Redistributions of source code must retain the above copyright 7// notice, this list of conditions and the following disclaimer. 8// * Redistributions in binary form must reproduce the above 9// copyright notice, this list of conditions and the following 10// disclaimer in the documentation and/or other materials provided 11// with the distribution. 12// * Neither the name of Google Inc. nor the names of its 13// contributors may be used to endorse or promote products derived 14// from this software without specific prior written permission. 15// 16// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 28// Flags: --allow-natives-syntax 29 30[Math.log10, Math.log2].forEach( function(fun) { 31 assertTrue(isNaN(fun(NaN))); 32 assertTrue(isNaN(fun(fun))); 33 assertTrue(isNaN(fun({ toString: function() { return NaN; } }))); 34 assertTrue(isNaN(fun({ valueOf: function() { return -1; } }))); 35 assertTrue(isNaN(fun({ valueOf: function() { return "abc"; } }))); 36 assertTrue(isNaN(fun(-0.1))); 37 assertTrue(isNaN(fun(-1))); 38 assertEquals("-Infinity", String(fun(0))); 39 assertEquals("-Infinity", String(fun(-0))); 40 assertEquals(0, fun(1)); 41 assertEquals("Infinity", String(fun(Infinity))); 42}); 43 44for (var i = -310; i <= 308; i += 0.5) { 45 assertEquals(i, Math.log10(Math.pow(10, i))); 46 // Square roots are tested below. 47 if (i != -0.5 && i != 0.5) assertEquals(i, Math.log2(Math.pow(2, i))); 48} 49 50// Test denormals. 51assertEquals(-307.77759430519706, Math.log10(1.5 * Math.pow(2, -1023))); 52 53// Issue 4025. Remove delta once issue 4029 has been fixed. 54assertEqualsDelta(-9.643274665532873e-17, Math.log10(1-Number.EPSILON), 3e-32); 55 56// Test Math.log2(2^k) for -1074 <= k <= 1023. 57var n = -1074; 58// This loop covers n from -1074 to -1043 59for (var lowbits = 1; lowbits <= 0x80000000; lowbits *= 2) { 60 var x = %ConstructDouble(0, lowbits); 61 assertEquals(n, Math.log2(x)); 62 n++; 63} 64// This loop covers n from -1042 to -1023 65for (var hibits = 1; hibits <= 0x80000; hibits *= 2) { 66 var x = %ConstructDouble(hibits, 0); 67 assertEquals(n, Math.log2(x)); 68 n++; 69} 70// The rest of the normal values of 2^n 71var x = 1; 72for (var n = -1022; n <= 1023; ++n) { 73 var x = Math.pow(2, n); 74 assertEquals(n, Math.log2(x)); 75} 76 77// Test special values. 78// Expectation isn't exactly 1/2 because Math.SQRT2 isn't exactly sqrt(2). 79assertEquals(0.5000000000000001, Math.log2(Math.SQRT2)); 80 81// Expectation isn't exactly -1/2 because Math.SQRT1_2 isn't exactly sqrt(1/2). 82assertEquals(-0.4999999999999999, Math.log2(Math.SQRT1_2)); 83 84assertEquals(3.321928094887362, Math.log2(10)); 85assertEquals(6.643856189774724, Math.log2(100)); 86 87// Test relationships 88x = 1; 89for (var k = 0; k < 1000; ++k) { 90 var y = Math.abs(Math.log2(x) + Math.log2(1/x)); 91 assertEqualsDelta(0, y, 1.5e-14); 92 x *= 1.1; 93} 94 95x = Math.pow(2, -100); 96for (var k = 0; k < 1000; ++k) { 97 var y = Math.log2(x); 98 var expected = Math.log(x) / Math.LN2; 99 var err = Math.abs(y - expected) / expected; 100 assertEqualsDelta(0, err, 1e-15); 101 x *= 1.1; 102} 103