MIPS: Add big-endian support for MIPS.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 1f656bc0b50bbc0f1ad27a19e6345ced0a244515..a3765e3210c47171f6f8eb68acba13dde7163787 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -1953,11 +1953,18 @@ class HeapNumber: public HeapObject {
   // Layout description.
   static const int kValueOffset = HeapObject::kHeaderSize;
   // IEEE doubles are two 32 bit words.  The first is just mantissa, the second
-  // is a mixture of sign, exponent and mantissa.  Our current platforms are all
-  // little endian apart from non-EABI arm which is little endian with big
-  // endian floating point word ordering!
+  // is a mixture of sign, exponent and mantissa. The offsets of two 32 bit
+  // words within double numbers are endian dependent and they are set
+  // accordingly.
+#if __BYTE_ORDER == __LITTLE_ENDIAN

[Jakob Kummerow, 2014/04/15 08:11:20]

Any reason this doesn't use V8_TARGET_LITTLE_ENDIAN?

[dusmil, 2014/04/15 15:22:22]

It is used to keep consistency because there are other ifdef uses of BYTE_ORDER
in this file. I change all of them to check V8_TARGET_LITTLE_ENDIAN and
V8_TARGET_BIG_ENDIAN now.

[dusmil, 2014/04/15 15:22:22]

Done.

   static const int kMantissaOffset = kValueOffset;
   static const int kExponentOffset = kValueOffset + 4;
+#elif __BYTE_ORDER == __BIG_ENDIAN
+  static const int kMantissaOffset = kValueOffset + 4;
+  static const int kExponentOffset = kValueOffset;
+#else
+#error Unknown byte ordering
+#endif
 
   static const int kSize = kValueOffset + kDoubleSize;
   static const uint32_t kSignMask = 0x80000000u;