MIPS: Add rounding support in simulator and RINT instruction.

src/mips64/disasm-mips64.cc

Index: src/mips64/disasm-mips64.cc
diff --git a/src/mips64/disasm-mips64.cc b/src/mips64/disasm-mips64.cc
index 29b069580de67447a9e29c93eda2b7c9fefdeb46..dc43769feac60a78c13c88cc2116254ad6627c57 100644
--- a/src/mips64/disasm-mips64.cc
+++ b/src/mips64/disasm-mips64.cc
@@ -517,6 +517,9 @@ int Decoder::DecodeBreakInstr(Instruction* instr) {
 
 bool Decoder::DecodeTypeRegisterRsType(Instruction* instr) {
   switch (instr->FunctionFieldRaw()) {
+    case RINT:
+      Format(instr, "rint.'t    'fd, 'fs");
+      break;
     case SELEQZ_C:
       Format(instr, "seleqz.'t    'fd, 'fs, 'ft");
       break;