MIPS: Add rounding support in simulator and RINT instruction.

src/mips64/assembler-mips64.cc

Index: src/mips64/assembler-mips64.cc
diff --git a/src/mips64/assembler-mips64.cc b/src/mips64/assembler-mips64.cc
index 0a8c1fb4726b036eb06433dcb06dcaf61e693134..094c85535da6c07925962a4da10029c33a7494ec 100644
--- a/src/mips64/assembler-mips64.cc
+++ b/src/mips64/assembler-mips64.cc
@@ -2408,6 +2408,13 @@ void Assembler::ceil_w_d(FPURegister fd, FPURegister fs) {
 }
 
 
+void Assembler::rint(SecondaryField fmt, FPURegister fd, FPURegister fs) {
+  DCHECK(kArchVariant == kMips64r6);
+  DCHECK((fmt == D) || (fmt == S));
+  GenInstrRegister(COP1, fmt, f0, fs, fd, RINT);
+}
+
+
 void Assembler::cvt_l_s(FPURegister fd, FPURegister fs) {
   DCHECK(kArchVariant == kMips64r2);
   GenInstrRegister(COP1, S, f0, fs, fd, CVT_L_S);