Calling convention support for cross 64/32 compilation.

Add REX support for x86-64 operands.

Change-Id: I093ae26fb8c111d54b8c72166f054984564c04c6
diff --git a/compiler/jni/quick/mips/calling_convention_mips.h b/compiler/jni/quick/mips/calling_convention_mips.h
index 1a9053a..e33fbad 100644
--- a/compiler/jni/quick/mips/calling_convention_mips.h
+++ b/compiler/jni/quick/mips/calling_convention_mips.h
@@ -21,10 +21,13 @@
 
 namespace art {
 namespace mips {
+
+constexpr size_t kFramePointerSize = 4;
+
 class MipsManagedRuntimeCallingConvention FINAL : public ManagedRuntimeCallingConvention {
  public:
   MipsManagedRuntimeCallingConvention(bool is_static, bool is_synchronized, const char* shorty)
-      : ManagedRuntimeCallingConvention(is_static, is_synchronized, shorty) {}
+      : ManagedRuntimeCallingConvention(is_static, is_synchronized, shorty, kFramePointerSize) {}
   ~MipsManagedRuntimeCallingConvention() OVERRIDE {}
   // Calling convention
   ManagedRegister ReturnRegister() OVERRIDE;