ARM optimize loading of immediates.

src/arm/simulator-arm.cc

Index: src/arm/simulator-arm.cc
diff --git a/src/arm/simulator-arm.cc b/src/arm/simulator-arm.cc
index cee5aea0d31b0fbe3385d8721b6ac0611b78641c..92048e30bf683d7e65af04b9d1d8f55a1d2e3da8 100644
--- a/src/arm/simulator-arm.cc
+++ b/src/arm/simulator-arm.cc
@@ -939,6 +939,7 @@ int32_t Simulator::GetShiftRm(Instr* instr, bool* carry_out) {
   if (instr->Bit(4) == 0) {
     // by immediate
     if ((shift == ROR) && (shift_amount == 0)) {
+      // RRX.
       UNIMPLEMENTED();
       return result;
     } else if (((shift == LSR) || (shift == ASR)) && (shift_amount == 0)) {
@@ -988,7 +989,11 @@ int32_t Simulator::GetShiftRm(Instr* instr, bool* carry_out) {
       }
 
       case ROR: {
-        UNIMPLEMENTED();
+        uint32_t uresult = static_cast<uint32_t>(result);
+        uresult =
+            (uresult >> shift_amount) | (uresult << (32 - shift_amount));
+        *carry_out = (uresult >> 31) != 0;
+        result = static_cast<int32_t>(uresult);
         break;
       }