X87: [Atomics] Fix disassembly for ia32 xchg_b and xchg_w.

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 12 matching lines @@
 //------------------------------------------------------------------
 // Tables
 //------------------------------------------------------------------
 struct ByteMnemonic {
   int b;  // -1 terminates, otherwise must be in range (0..255)
   const char* mnem;
   OperandOrder op_order_;
 };
 
 static const ByteMnemonic two_operands_instr[] = {
-    {0x01, "add", OPER_REG_OP_ORDER},   {0x03, "add", REG_OPER_OP_ORDER},
-    {0x09, "or", OPER_REG_OP_ORDER},    {0x0B, "or", REG_OPER_OP_ORDER},
-    {0x13, "adc", REG_OPER_OP_ORDER},   {0x1B, "sbb", REG_OPER_OP_ORDER},
-    {0x21, "and", OPER_REG_OP_ORDER},   {0x23, "and", REG_OPER_OP_ORDER},
-    {0x29, "sub", OPER_REG_OP_ORDER},   {0x2A, "subb", REG_OPER_OP_ORDER},
-    {0x2B, "sub", REG_OPER_OP_ORDER},   {0x31, "xor", OPER_REG_OP_ORDER},
-    {0x33, "xor", REG_OPER_OP_ORDER},   {0x38, "cmpb", OPER_REG_OP_ORDER},
-    {0x39, "cmp", OPER_REG_OP_ORDER},   {0x3A, "cmpb", REG_OPER_OP_ORDER},
-    {0x3B, "cmp", REG_OPER_OP_ORDER},   {0x84, "test_b", REG_OPER_OP_ORDER},
-    {0x85, "test", REG_OPER_OP_ORDER},  {0x87, "xchg", REG_OPER_OP_ORDER},
-    {0x8A, "mov_b", REG_OPER_OP_ORDER}, {0x8B, "mov", REG_OPER_OP_ORDER},
-    {0x8D, "lea", REG_OPER_OP_ORDER},   {-1, "", UNSET_OP_ORDER}};
+    {0x01, "add", OPER_REG_OP_ORDER},  {0x03, "add", REG_OPER_OP_ORDER},
+    {0x09, "or", OPER_REG_OP_ORDER},   {0x0B, "or", REG_OPER_OP_ORDER},
+    {0x13, "adc", REG_OPER_OP_ORDER},  {0x1B, "sbb", REG_OPER_OP_ORDER},
+    {0x21, "and", OPER_REG_OP_ORDER},  {0x23, "and", REG_OPER_OP_ORDER},
+    {0x29, "sub", OPER_REG_OP_ORDER},  {0x2A, "subb", REG_OPER_OP_ORDER},
+    {0x2B, "sub", REG_OPER_OP_ORDER},  {0x31, "xor", OPER_REG_OP_ORDER},
+    {0x33, "xor", REG_OPER_OP_ORDER},  {0x38, "cmpb", OPER_REG_OP_ORDER},
+    {0x39, "cmp", OPER_REG_OP_ORDER},  {0x3A, "cmpb", REG_OPER_OP_ORDER},
+    {0x3B, "cmp", REG_OPER_OP_ORDER},  {0x84, "test_b", REG_OPER_OP_ORDER},
+    {0x85, "test", REG_OPER_OP_ORDER}, {0x86, "xchg_b", REG_OPER_OP_ORDER},
+    {0x87, "xchg", REG_OPER_OP_ORDER}, {0x8A, "mov_b", REG_OPER_OP_ORDER},
+    {0x8B, "mov", REG_OPER_OP_ORDER},  {0x8D, "lea", REG_OPER_OP_ORDER},
+    {-1, "", UNSET_OP_ORDER}};
 
 static const ByteMnemonic zero_operands_instr[] = {
   {0xC3, "ret", UNSET_OP_ORDER},
   {0xC9, "leave", UNSET_OP_ORDER},
   {0x90, "nop", UNSET_OP_ORDER},
   {0xF4, "hlt", UNSET_OP_ORDER},
   {0xCC, "int3", UNSET_OP_ORDER},
   {0x60, "pushad", UNSET_OP_ORDER},
   {0x61, "popad", UNSET_OP_ORDER},
   {0x9C, "pushfd", UNSET_OP_ORDER},
@@ skipping 1205 matching lines @@
 
       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) {
           data++;
           data += PrintOperands("mov_w", REG_OPER_OP_ORDER, data);
+        } else if (*data == 0x87) {
+          data++;
+          int mod, regop, rm;
+          get_modrm(*data, &mod, &regop, &rm);
+          AppendToBuffer("xchg_w ");
+          data += PrintRightOperand(data);
+          AppendToBuffer(",%s", NameOfCPURegister(regop));
         } 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 == 0xC7) {
           data++;
           AppendToBuffer("%s ", "mov_w");
@@ skipping 537 matching lines @@
       fprintf(f, "  ");
     }
     fprintf(f, "  %s\n", buffer.start());
   }
 }
 
 
 }  // namespace disasm
 
 #endif  // V8_TARGET_ARCH_X87