eal: introduce atomic exchange operation

[dpdk.git] / lib / librte_eal / common / include / arch / x86 / rte_atomic_32.h

diff --git a/lib/librte_eal/common/include/arch/x86/rte_atomic_32.h b/lib/librte_eal/common/include/arch/x86/rte_atomic_32.h
index 400d8a9..8d711b6 100644 (file)
--- a/lib/librte_eal/common/include/arch/x86/rte_atomic_32.h
+++ b/lib/librte_eal/common/include/arch/x86/rte_atomic_32.h
@@ -37,9 +37,17 @@
  * All rights reserved.
  */
 
+#ifndef _RTE_ATOMIC_X86_H_
+#error do not include this file directly, use <rte_atomic.h> instead
+#endif
+
 #ifndef _RTE_ATOMIC_I686_H_
 #define _RTE_ATOMIC_I686_H_
 
+#include <stdint.h>
+#include <rte_common.h>
+#include <rte_atomic.h>
+
 /*------------------------- 64 bit atomic operations -------------------------*/
 
 #ifndef RTE_FORCE_INTRINSICS
@@ -47,6 +55,7 @@ static inline int
 rte_atomic64_cmpset(volatile uint64_t *dst, uint64_t exp, uint64_t src)
 {
        uint8_t res;
+       RTE_STD_C11
        union {
                struct {
                        uint32_t l32;
@@ -72,7 +81,7 @@ rte_atomic64_cmpset(volatile uint64_t *dst, uint64_t exp, uint64_t src)
                        : "memory" );           /* no-clobber list */
 #else
        asm volatile (
-            "mov %%ebx, %%edi\n"
+            "xchgl %%ebx, %%edi;\n"
                        MPLOCKED
                        "cmpxchg8b (%[dst]);"
                        "setz %[res];"
@@ -89,6 +98,18 @@ rte_atomic64_cmpset(volatile uint64_t *dst, uint64_t exp, uint64_t src)
        return res;
 }
 
+static inline uint64_t
+rte_atomic64_exchange(volatile uint64_t *dest, uint64_t val)
+{
+       uint64_t old;
+
+       do {
+               old = *dest;
+       } while (rte_atomic64_cmpset(dest, old, val));
+
+       return old;
+}
+
 static inline void
 rte_atomic64_init(rte_atomic64_t *v)
 {