Harmony: implement Math.log2 and Math.log10.

R=jarin@chromium.org
BUG=v8:2938
LOG=N

Review URL: https://codereview.chromium.org/119093006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@18406 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/harmony-math.js

@@ -110,6 +110,18 @@ function MathAtanh(x) {
 }
 
 
+//ES6 draft 09-27-13, section 20.2.2.21.
+function MathLog10(x) {
+  return MathLog(x) * 0.434294481903251828;  // log10(x) = log(x)/log(10).
+}
+
+
+//ES6 draft 09-27-13, section 20.2.2.22.
+function MathLog2(x) {
+  return MathLog(x) * 1.442695040888963407;  // log2(x) = log(x)/log(2).
+}
+
+
 function ExtendMath() {
   %CheckIsBootstrapping();
 
@@ -122,7 +134,9 @@ function ExtendMath() {
     "tanh", MathTanh,
     "asinh", MathAsinh,
     "acosh", MathAcosh,
-    "atanh", MathAtanh
+    "atanh", MathAtanh,
+    "log10", MathLog10,
+    "log2", MathLog2
   ));
 }
 

test/mjsunit/harmony/math-log2-log10.js

+// Copyright 2013 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Flags: --harmony-maths
+
+[Math.log10, Math.log2].forEach( function(fun) {
+  assertTrue(isNaN(fun(NaN)));
+  assertTrue(isNaN(fun(fun)));
+  assertTrue(isNaN(fun({ toString: function() { return NaN; } })));
+  assertTrue(isNaN(fun({ valueOf: function() { return -1; } })));
+  assertTrue(isNaN(fun({ valueOf: function() { return "abc"; } })));
+  assertTrue(isNaN(fun(-0.1)));
+  assertTrue(isNaN(fun(-1)));
+  assertEquals("-Infinity", String(fun(0)));
+  assertEquals("-Infinity", String(fun(-0)));
+  assertEquals(0, fun(1));
+  assertEquals("Infinity", String(fun(Infinity)));
+});
+
+for (var i = -300; i < 300; i += 0.7) {
+  assertEqualsDelta(i, Math.log10(Math.pow(10, i)), 1E-13);
+  assertEqualsDelta(i, Math.log2(Math.pow(2, i)), 1E-13);
+}