Implement byte swapping instructions on MIPS32 and MIPS64.

src/mips/constants-mips.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef  V8_MIPS_CONSTANTS_H_
 #define  V8_MIPS_CONSTANTS_H_
 #include "src/globals.h"
 // UNIMPLEMENTED_ macro for MIPS.
 #ifdef DEBUG
 #define UNIMPLEMENTED_MIPS()                                                  \
@@ skipping 1168 matching lines @@
       break;
     case SPECIAL3:
       switch (FunctionFieldRaw()) {
         case INS:
         case EXT:
           return kRegisterType;
         case BSHFL: {
           int sa = SaFieldRaw() >> kSaShift;
           switch (sa) {
             case BITSWAP:
-              return kRegisterType;
             case WSBH:
             case SEB:
             case SEH:
-              return kUnsupported;
+              return kRegisterType;
           }
           sa >>= kBp2Bits;
           switch (sa) {
             case ALIGN:
               return kRegisterType;
             default:
               return kUnsupported;
           }
         }
         default:
@@ skipping 26 matching lines @@
       }
   }
 }
 
 #undef OpcodeToBitNumber
 #undef FunctionFieldToBitNumber
 }  // namespace internal
 }  // namespace v8
 
 #endif    // #ifndef V8_MIPS_CONSTANTS_H_