diff --git a/qemu/target/i386/mem_helper.c b/qemu/target/i386/mem_helper.c
index 428ff9c3..1a9dfd8f 100644
--- a/qemu/target/i386/mem_helper.c
+++ b/qemu/target/i386/mem_helper.c
@@ -23,6 +23,7 @@
 #include "exec/exec-all.h"
 #include "exec/cpu_ldst.h"
 #include "qemu/int128.h"
+#include "qemu/atomic128.h"
 #include "tcg.h"
 
 #include "uc_priv.h"
@@ -139,10 +140,7 @@ void helper_cmpxchg16b(CPUX86State *env, target_ulong a0)
 
     if ((a0 & 0xf) != 0) {
         raise_exception_ra(env, EXCP0D_GPF, ra);
-    } else {
-#ifndef CONFIG_ATOMIC128
-        cpu_loop_exit_atomic(ENV_GET_CPU(env), ra);
-#else
+    } else if (HAVE_CMPXCHG128) {
         int eflags = cpu_cc_compute_all(env, CC_OP);
 
         Int128 cmpv = int128_make128(env->regs[R_EAX], env->regs[R_EDX]);
@@ -161,7 +159,8 @@ void helper_cmpxchg16b(CPUX86State *env, target_ulong a0)
             eflags &= ~CC_Z;
         }
         CC_SRC = eflags;
-#endif
+    } else {
+        cpu_loop_exit_atomic(ENV_GET_CPU(env), ra);
     }
 }
 #endif