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

test/cctest/test-disasm-x64.cc

Index: test/cctest/test-disasm-x64.cc
diff --git a/test/cctest/test-disasm-x64.cc b/test/cctest/test-disasm-x64.cc
index b855626cee33277f26a5480c175912de60db5934..59ad683ba4e684a780a9cc7c69b20ef077247a35 100644
--- a/test/cctest/test-disasm-x64.cc
+++ b/test/cctest/test-disasm-x64.cc
@@ -745,12 +745,31 @@ TEST(DisasmX64) {
 
   // xchg.
   {
+    __ xchgb(rax, Operand(rax, 8));
+    __ xchgw(rax, Operand(rbx, 8));
     __ xchgq(rax, rax);
     __ xchgq(rax, rbx);
     __ xchgq(rbx, rbx);
     __ xchgq(rbx, Operand(rsp, 12));
   }
 
+  // cmpxchg.
+  {
+    __ cmpxchgb(Operand(rsp, 12), rax);
+    __ cmpxchgw(Operand(rbx, rcx, times_4, 10000), rax);
+    __ cmpxchgl(Operand(rbx, rcx, times_4, 10000), rax);
+    __ cmpxchgq(Operand(rbx, rcx, times_4, 10000), rax);
+  }
+
+  // lock prefix.
+  {
+    __ lock();
+    __ cmpxchgl(Operand(rsp, 12), rbx);
+
+    __ lock();
+    __ xchgw(rax, Operand(rcx, 8));
+  }
+
   // Nop instructions
   for (int i = 0; i < 16; i++) {
     __ Nop(i);