Math.abs rewrited to not use Runtime.

Review URL: http://codereview.chromium.org/799006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4093 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/math.js

@@ -45,7 +45,8 @@ $Math.__proto__ = global.Object.prototype;
 function MathAbs(x) {
   if (%_IsSmi(x)) return x >= 0 ? x : -x;
   if (!IS_NUMBER(x)) x = ToNumber(x);
-  return %Math_abs(x);
+  if (x === 0) return 0;  // To handle -0.
+  return x > 0 ? x : -x;
 }
 
 // ECMA 262 - 15.8.2.2

src/runtime.cc

@@ -4847,16 +4847,6 @@ static Object* Runtime_StringCompare(Arguments args) {
 }
 
 
-static Object* Runtime_Math_abs(Arguments args) {
-  NoHandleAllocation ha;
-  ASSERT(args.length() == 1);
-  Counters::math_abs.Increment();
-
-  CONVERT_DOUBLE_CHECKED(x, args[0]);
-  return Heap::AllocateHeapNumber(fabs(x));
-}
-
-
 static Object* Runtime_Math_acos(Arguments args) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);

src/runtime.h

@@ -132,7 +132,6 @@ namespace internal {
   F(StringCompare, 2, 1) \
   \
   /* Math */ \
-  F(Math_abs, 1, 1) \
   F(Math_acos, 1, 1) \
   F(Math_asin, 1, 1) \
   F(Math_atan, 1, 1) \

src/v8-counters.h

@@ -170,7 +170,6 @@ namespace internal {
   SC(regexp_entry_native, V8.RegExpEntryNative)                       \
   SC(number_to_string_native, V8.NumberToStringNative)                \
   SC(number_to_string_runtime, V8.NumberToStringRuntime)              \
-  SC(math_abs, V8.MathAbs)                                            \
   SC(math_acos, V8.MathAcos)                                          \
   SC(math_asin, V8.MathAsin)                                          \
   SC(math_atan, V8.MathAtan)                                          \

test/mjsunit/abs.js

+// Copyright 2010 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.
+
+// Test Math.sin and Math.abs.
+
+assertEquals(1, Math.abs(1));  // Positive SMI.
+assertEquals(1, Math.abs(-1));  // Negative SMI.
+assertEquals(0.5, Math.abs(0.5));  // Positive double.
+assertEquals(0.5, Math.abs(-0.5));  // Negative double.
+assertEquals('Infinity', Math.abs(Number('+Infinity').toString()));
+assertEquals('Infinity', Math.abs(Number('-Infinity').toString()));
+assertEquals('NaN', Math.abs(NaN).toString());
+assertEquals('NaN', Math.abs(-NaN).toString());
+
+var minusZero = 1 / (-1 / 0);
+function isMinusZero(x) {
+  return x === 0 && 1 / x < 0;
+}
+
+assertTrue(!isMinusZero(0));
+assertTrue(isMinusZero(minusZero));
+assertEquals(0, Math.abs(minusZero));
+assertTrue(!isMinusZero(Math.abs(minusZero)));
+assertTrue(!isMinusZero(Math.abs(0.0)));