MIPS: [turbofan] Support for %_DoubleHi, %_DoubleLo and %_ConstructDouble.

src/mips64/macro-assembler-mips64.cc

Index: src/mips64/macro-assembler-mips64.cc
diff --git a/src/mips64/macro-assembler-mips64.cc b/src/mips64/macro-assembler-mips64.cc
index d187fa5423702ddb8dc42648043a090d2605c48d..fbd5520be8a6998cdeaecdb300a237c4d30d4b6a 100644
--- a/src/mips64/macro-assembler-mips64.cc
+++ b/src/mips64/macro-assembler-mips64.cc
@@ -1717,6 +1717,14 @@ void MacroAssembler::BranchF(Label* target,
 }
 
 
+void MacroAssembler::FmoveLow(FPURegister dst, Register src_low) {
+  DCHECK(!src_low.is(at));
+  mfhc1(at, dst);
+  mtc1(src_low, dst);
+  mthc1(at, dst);
+}
+
+
 void MacroAssembler::Move(FPURegister dst, float imm) {
   li(at, Operand(bit_cast<int32_t>(imm)));
   mtc1(at, dst);