Update 386 cmpxchg support

[urcu.git] / urcu / uatomic_arch_x86.h

diff --git a/urcu/uatomic_arch_x86.h b/urcu/uatomic_arch_x86.h
index fccea8e2d350321ebe9cbf4517a68866e4b5fa19..dfb58763a37259b88a8962f9bd607767d5c59a3a 100644 (file)
--- a/urcu/uatomic_arch_x86.h
+++ b/urcu/uatomic_arch_x86.h
@@ -402,7 +402,13 @@ void _uatomic_dec(void *addr, int len)
 #define compat_uatomic_cmpxchg(ptr, old, _new) uatomic_cmpxchg(ptr, old, _new)
 #else
 extern int __urcu_cas_avail;
-#define URCU_CAS_AVAIL()       __urcu_cas_avail
+extern int __urcu_cas_init(void);
+#define URCU_CAS_AVAIL()                                               \
+               ((likely(__urcu_cas_avail > 0)) ?                       \
+                       (1) :                                           \
+                       ((unlikely(__urcu_cas_avail < 0) ?              \
+                               (__urcu_cas_init()) :                   \
+                               (0))))
 
 extern unsigned long _compat_uatomic_cmpxchg(void *addr, unsigned long old,
                              unsigned long _new, int len);