Harmony: implement Math.cbrt in Javascript.

src/runtime.cc

 // Copyright 2012 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
@@ skipping 7690 matching lines @@
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ConstructDouble) {
   SealHandleScope shs(isolate);
   ASSERT(args.length() == 2);
   CONVERT_NUMBER_CHECKED(uint32_t, hi, Uint32, args[0]);
   CONVERT_NUMBER_CHECKED(uint32_t, lo, Uint32, args[1]);
   uint64_t result = (static_cast<uint64_t>(hi) << 32) | lo;
   return isolate->heap()->AllocateHeapNumber(uint64_to_double(result));
 }
 
 
-// Cube root approximation, refer to: http://metamerist.com/cbrt/cbrt.htm
-// Using initial approximation adapted from Kahan's cbrt and 4 iterations
-// of Newton's method.
-inline double CubeRootNewtonIteration(double approx, double x) {
-  return (1.0 / 3.0) * (x / (approx * approx) + 2 * approx);
-}
-
-
-inline double CubeRoot(double x) {
-  static const uint64_t magic = V8_2PART_UINT64_C(0x2A9F7893, 00000000);
-  uint64_t xhigh = double_to_uint64(x);
-  double approx = uint64_to_double(xhigh / 3 + magic);
-
-  approx = CubeRootNewtonIteration(approx, x);
-  approx = CubeRootNewtonIteration(approx, x);
-  approx = CubeRootNewtonIteration(approx, x);
-  return CubeRootNewtonIteration(approx, x);
-}
-
-
-RUNTIME_FUNCTION(MaybeObject*, Runtime_Math_cbrt) {
-  SealHandleScope shs(isolate);
-  ASSERT(args.length() == 1);
-  CONVERT_DOUBLE_ARG_CHECKED(x, 0);
-  if (x == 0 || std::isinf(x)) return args[0];
-  double result = (x > 0) ? CubeRoot(x) : -CubeRoot(-x);
-  return isolate->heap()->AllocateHeapNumber(result);
-}
-
-
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Math_log1p) {
   SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
 
   double x_abs = std::fabs(x);
   // Use Taylor series to approximate. With y = x + 1;
   // log(y) at 1 == log(1) + log'(1)(y-1)/1! + log''(1)(y-1)^2/2! + ...
   //             == 0 + x - x^2/2 + x^3/3 ...
   // The closer x is to 0, the fewer terms are required.
@@ skipping 7270 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal