Implement byte swapping instructions on MIPS32 and MIPS64.

src/mips64/disasm-mips64.cc

 // 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.
 
 // A Disassembler object is used to disassemble a block of code instruction by
 // instruction. The default implementation of the NameConverter object can be
 // overriden to modify register names or to do symbol lookup on addresses.
 //
 // The example below will disassemble a block of code and print it to stdout.
 //
@@ skipping 1439 matching lines @@
       Format(instr, "dext    'rt, 'rs, 'sa, 'ss1");
       break;
     }
     case BSHFL: {
       int sa = instr->SaFieldRaw() >> kSaShift;
       switch (sa) {
         case BITSWAP: {
           Format(instr, "bitswap 'rd, 'rt");
           break;
         }
-        case SEB:
-        case SEH:
-        case WSBH:
-          UNREACHABLE();
+        case SEB: {
+          Format(instr, "seb     'rd, 'rt");
           break;
+        }
+        case SEH: {
+          Format(instr, "seh     'rd, 'rt");
+          break;
+        }
+        case WSBH: {
+          Format(instr, "wsbh    'rd, 'rt");
+          break;
+        }
         default: {
           sa >>= kBp2Bits;
           switch (sa) {
             case ALIGN: {
               Format(instr, "align  'rd, 'rs, 'rt, 'bp2");
               break;
             }
             default:
               UNREACHABLE();
               break;
@@ skipping 10 matching lines @@
           switch (instr->SaFieldRaw() >> kSaShift) {
             case DBITSWAP_SA:
               Format(instr, "dbitswap 'rd, 'rt");
               break;
             default:
               UNREACHABLE();
               break;
           }
           break;
         }
-        case DSBH:
-        case DSHD:
-          UNREACHABLE();
+        case DSBH: {
+          Format(instr, "dsbh    'rd, 'rt");
           break;
+        }
+        case DSHD: {
+          Format(instr, "dshd    'rd, 'rt");
+          break;
+        }
         default: {
           sa >>= kBp3Bits;
           switch (sa) {
             case DALIGN: {
               Format(instr, "dalign  'rd, 'rs, 'rt, 'bp3");
               break;
             }
             default:
               UNREACHABLE();
               break;
@@ skipping 496 matching lines @@
                          *reinterpret_cast<int32_t*>(prev_pc), buffer.start());
   }
 }
 
 
 #undef UNSUPPORTED
 
 }  // namespace disasm
 
 #endif  // V8_TARGET_ARCH_MIPS64