Take ARM big-endian floating point numbers into account in FastD2UI.

src/conversions-inl.h

 // Copyright 2006-2008 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 42 matching lines @@
   // towards zero is implied by the C standard. This means that the
   // status register of the FPU has to be changed with the 'fldcw'
   // instruction. This completely stalls the pipeline and takes many
   // hundreds of clock cycles.
   return static_cast<int>(x);
 #endif
 }
 
 
 // The fast double-to-unsigned-int conversion routine does not guarantee
-// rounding towards zero.
+// rounding towards zero, or any reasonable value if the argument is larger
+// than what fits in an unsigned 32-bit integer.
 static inline unsigned int FastD2UI(double x) {
   // There is no unsigned version of lrint, so there is no fast path
   // in this function as there is in FastD2I. Using lrint doesn't work
   // for values of 2^31 and above.
 
   // Convert "small enough" doubles to uint32_t by fixing the 32
   // least significant non-fractional bits in the low 32 bits of the
   // double, and reading them from there.
   const double k2Pow52 = 4503599627370496.0;
   bool negative = x < 0;
   if (negative) {
     x = -x;
   }
   if (x < k2Pow52) {
     x += k2Pow52;
     uint32_t result;
-    memcpy(&result, &x, sizeof(result));  // Copy low 32 bits.
+    Address mantissa_ptr;
+#ifdef BIG_ENDIAN_FLOATING_POINT
+    mantissa_ptr = reinterpret_cast<Address>(&x) + kIntSize;
+#else
+    mantissa_ptr = reinterpret_cast<Address>(&x);
+#endif
+    memcpy(&result, mantissa_ptr, sizeof(result));  // Copy low 32 bits.

[Erik Corry, 2010/03/16 12:12:15]

Comment is out of date!

     return negative ? ~result + 1 : result;
   }
   // Large number (outside uint32 range), Infinity or NaN.
   return 0x80000000u;  // Return integer indefinite.
 }
 
 
 static inline double DoubleToInteger(double x) {
   if (isnan(x)) return 0;
   if (!isfinite(x) || x == 0) return x;
@@ skipping 21 matching lines @@
   if (!isfinite(x) || x == 0) return 0;
   if (x < 0 || x >= two32) x = modulo(x, two32);
   x = (x >= 0) ? floor(x) : ceil(x) + two32;
   return (int32_t) ((x >= two31) ? x - two32 : x);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_CONVERSIONS_INL_H_