Implement optional turbofan UnalignedLoad and UnalignedStore operators

src/mips/constants-mips.h

Index: src/mips/constants-mips.h
diff --git a/src/mips/constants-mips.h b/src/mips/constants-mips.h
index 49142515c7648f32be6e7d8e38208808d1656673..1aac2dc54c07793cab92d093187d7e3421e4fda8 100644
--- a/src/mips/constants-mips.h
+++ b/src/mips/constants-mips.h
@@ -108,6 +108,19 @@ const uint32_t kHoleNanLower32Offset = 4;
   (CpuFeatures::IsSupported(static_cast<CpuFeature>(check)))
 #endif
 
+#if defined(V8_TARGET_LITTLE_ENDIAN)
+const uint32_t kMipsLwrOffset = 0;
+const uint32_t kMipsLwlOffset = 3;
+const uint32_t kMipsSwrOffset = 0;
+const uint32_t kMipsSwlOffset = 3;
+#elif defined(V8_TARGET_BIG_ENDIAN)
+const uint32_t kMipsLwrOffset = 3;
+const uint32_t kMipsLwlOffset = 0;
+const uint32_t kMipsSwrOffset = 3;
+const uint32_t kMipsSwlOffset = 0;
+#else
+#error Unknown endianness
+#endif
 
 #define __STDC_FORMAT_MACROS
 #include <inttypes.h>