X87: [ia32] Fixes a bug in cmpw.

src/x87/disasm-x87.cc

 // Copyright 2011 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.
 
 #include <assert.h>
 #include <stdarg.h>
 #include <stdio.h>
 
 #if V8_TARGET_ARCH_X87
 
@@ skipping 1271 matching lines @@
             data += PrintRightOperand(data);
             AppendToBuffer(",%s", NameOfCPURegister(regop));
           }
         }
         break;
 
       case 0x66:  // prefix
         while (*data == 0x66) data++;
         if (*data == 0xf && data[1] == 0x1f) {
           AppendToBuffer("nop");  // 0x66 prefix
-        } else if (*data == 0x90) {
-          AppendToBuffer("nop");  // 0x66 prefix
-        } else if (*data == 0x8B) {
+        } else if (*data == 0x39) {
           data++;
-          data += PrintOperands("mov_w", REG_OPER_OP_ORDER, data);
+          data += PrintOperands("cmpw", OPER_REG_OP_ORDER, data);
+        } else if (*data == 0x3B) {
+          data++;
+          data += PrintOperands("cmpw", REG_OPER_OP_ORDER, data);
+        } else if (*data == 0x81) {
+          data++;
+          AppendToBuffer("cmpw ");
+          data += PrintRightOperand(data);
+          int imm = *reinterpret_cast<int16_t*>(data);
+          AppendToBuffer(",0x%x", imm);
+          data += 2;
         } else if (*data == 0x87) {
           data++;
           int mod, regop, rm;
           get_modrm(*data, &mod, &regop, &rm);
           AppendToBuffer("xchg_w %s,", NameOfCPURegister(regop));
           data += PrintRightOperand(data);
         } else if (*data == 0x89) {
           data++;
           int mod, regop, rm;
           get_modrm(*data, &mod, &regop, &rm);
           AppendToBuffer("mov_w ");
           data += PrintRightOperand(data);
           AppendToBuffer(",%s", NameOfCPURegister(regop));
+        } else if (*data == 0x8B) {
+          data++;
+          data += PrintOperands("mov_w", REG_OPER_OP_ORDER, data);
+        } else if (*data == 0x90) {
+          AppendToBuffer("nop");  // 0x66 prefix
         } else if (*data == 0xC7) {
           data++;
           AppendToBuffer("%s ", "mov_w");
           data += PrintRightOperand(data);
           int imm = *reinterpret_cast<int16_t*>(data);
           AppendToBuffer(",0x%x", imm);
           data += 2;
         } else if (*data == 0xF7) {
           data++;
           AppendToBuffer("%s ", "test_w");
@@ skipping 533 matching lines @@
       fprintf(f, "  ");
     }
     fprintf(f, "  %s\n", buffer.start());
   }
 }
 
 
 }  // namespace disasm
 
 #endif  // V8_TARGET_ARCH_X87