Add cmpxchg and lock instructions to x64 and ia32 {dis,}assemblers

src/ia32/assembler-ia32.h

Index: src/ia32/assembler-ia32.h
diff --git a/src/ia32/assembler-ia32.h b/src/ia32/assembler-ia32.h
index c3edacb0ac5b369c6c76380baed92988cd327f2c..f2e7c6cfd44a64ed30c49aa5931c0d91343a9e56 100644
--- a/src/ia32/assembler-ia32.h
+++ b/src/ia32/assembler-ia32.h
@@ -662,6 +662,14 @@ class Assembler : public AssemblerBase {
   void xchg_b(Register reg, const Operand& op);
   void xchg_w(Register reg, const Operand& op);
 
+  // Lock prefix
+  void lock();
+
+  // CompareExchange
+  void cmpxchg(const Operand& dst, Register src);
+  void cmpxchg_b(const Operand& dst, Register src);
+  void cmpxchg_w(const Operand& dst, Register src);
+
   // Arithmetics
   void adc(Register dst, int32_t imm32);
   void adc(Register dst, const Operand& src);