Harmony: implement Math.cbrt, Math.expm1 and Math.log1p.

test/mjsunit/harmony/math-cbrt.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
+
+assertTrue(isNaN(Math.cbrt(NaN)));
+assertTrue(isNaN(Math.cbrt(function() {})));
+assertTrue(isNaN(Math.cbrt({ toString: function() { return NaN; } })));
+assertTrue(isNaN(Math.cbrt({ valueOf: function() { return "abc"; } })));
+assertEquals("Infinity", String(1/Math.cbrt(0)));
+assertEquals("-Infinity", String(1/Math.cbrt(-0)));
+assertEquals("Infinity", String(Math.cbrt(Infinity)));
+assertEquals("-Infinity", String(Math.cbrt(-Infinity)));
+
+for (var i = 1E-100; i < 1E100; i *= Math.PI) {
+  assertEqualsDelta(i, Math.cbrt(i*i*i), i * 1E-15);
+}
+
+for (var i = -1E-100; i > -1E100; i *= Math.E) {
+  assertEqualsDelta(i, Math.cbrt(i*i*i), -i * 1E-15);
+}
+
+// Let's be exact at least for small integers.
+for (var i = 2; i < 10000; i++) {
+  assertEquals(i, Math.cbrt(i*i*i));
+}