Added RELEASE and ACQUIRE-and-RELEASE versions of 32 bit CAS.
These are commonly needed operations in lock-free algorithms.
Signed-off-by: Petri Savolainen <petri.savolai...@nokia.com>
---
include/odp/api/atomic.h | 86 +++++++++++++++++++++++++++++++++++++-----------
1 file changed, 67 insertions(+), 19 deletions(-)
diff --git a/include/odp/api/atomic.h b/include/odp/api/atomic.h
index b0a46ba..aa20c61 100644
--- a/include/odp/api/atomic.h
+++ b/include/odp/api/atomic.h
@@ -31,7 +31,7 @@ extern "C" {
* before or after the operation), only atomicity of the operation itself is
* guaranteed.
*
- * <b> Operations with other than relaxed memory ordering </b>
+ * <b> Operations with non-relaxed memory ordering </b>
*
* <b> An operation with RELEASE </b> memory ordering
(odp_atomic_xxx_rel_xxx())
* ensures that other threads loading the same atomic variable with ACQUIRE
@@ -43,6 +43,11 @@ extern "C" {
* thread) that happened before a RELEASE memory ordered store to the same
* atomic variable.
*
+ * <b> An operation with ACQUIRE-and-RELEASE </b> memory ordering
+ * (odp_atomic_xxx_acq_rel_xxx()) combines the effects of ACQUIRE and RELEASE
+ * memory orders. A single operation acts as both an acquiring load and
+ * a releasing store.
+ *
* @{
*/
@@ -54,6 +59,11 @@ extern "C" {
* Atomic 32-bit unsigned integer
*/
+/*
+ * 32-bit operations in RELAXED memory ordering
+ * --------------------------------------------
+ */
+
/**
* Initialize atomic uint32 variable
*
@@ -188,6 +198,11 @@ void odp_atomic_min_u32(odp_atomic_u32_t *atom, uint32_t
new_min);
int odp_atomic_cas_u32(odp_atomic_u32_t *atom, uint32_t *old_val,
uint32_t new_val);
+/*
+ * 64-bit operations in RELAXED memory ordering
+ * --------------------------------------------
+ */
+
/**
* Initialize atomic uint64 variable
*
@@ -322,8 +337,8 @@ int odp_atomic_cas_u64(odp_atomic_u64_t *atom, uint64_t
*old_val,
uint64_t new_val);
/*
- * Operations with other than relaxed memory ordering
- * --------------------------------------------------
+ * 32-bit operations in non-RELAXED memory ordering
+ * ------------------------------------------------
*/
/**
@@ -339,22 +354,6 @@ int odp_atomic_cas_u64(odp_atomic_u64_t *atom, uint64_t
*old_val,
uint32_t odp_atomic_load_acq_u32(odp_atomic_u32_t *atom);
/**
- * Compare and swap atomic uint32 variable using ACQUIRE memory ordering
- *
- * Otherwise identical to odp_atomic_cas_u32() but ensures ACQUIRE memory
- * ordering.
- *
- * @param atom Pointer to atomic variable
- * @param[in,out] old_val Pointer to the old value of the atomic variable.
- * Operation updates this value on failure.
- * @param new_val New value to be written into the atomic variable
- *
- * @return 0 on failure, !0 on success
- */
-int odp_atomic_cas_acq_u32(odp_atomic_u32_t *atom, uint32_t *old_val,
- uint32_t new_val);
-
-/**
* Store value to atomic uint32 variable using RELEASE memory ordering
*
* Otherwise identical to odp_atomic_store_u32() but ensures RELEASE memory
@@ -388,6 +387,55 @@ void odp_atomic_add_rel_u32(odp_atomic_u32_t *atom,
uint32_t val);
void odp_atomic_sub_rel_u32(odp_atomic_u32_t *atom, uint32_t val);
/**
+ * Compare and swap atomic uint32 variable using ACQUIRE memory ordering
+ *
+ * Otherwise identical to odp_atomic_cas_u32() but ensures ACQUIRE memory
+ * ordering on success. Memory ordering is RELAXED on failure.
+ *
+ * @param atom Pointer to atomic variable
+ * @param[in,out] old_val Pointer to the old value of the atomic variable.
+ * Operation updates this value on failure.
+ * @param new_val New value to be written into the atomic variable
+ *
+ * @return 0 on failure, !0 on success
+ */
+int odp_atomic_cas_acq_u32(odp_atomic_u32_t *atom, uint32_t *old_val,
+ uint32_t new_val);
+
+/**
+ * Compare and swap atomic uint32 variable using RELEASE memory ordering
+ *
+ * Otherwise identical to odp_atomic_cas_u32() but ensures RELEASE memory
+ * ordering on success. Memory ordering is RELAXED on failure.
+ *
+ * @param atom Pointer to atomic variable
+ * @param[in,out] old_val Pointer to the old value of the atomic variable.
+ * Operation updates this value on failure.
+ * @param new_val New value to be written into the atomic variable
+ *
+ * @return 0 on failure, !0 on success
+ */
+int odp_atomic_cas_rel_u32(odp_atomic_u32_t *atom, uint32_t *old_val,
+ uint32_t new_val);
+
+/**
+ * Compare and swap atomic uint32 variable using ACQUIRE-and-RELEASE memory
+ * ordering
+ *
+ * Otherwise identical to odp_atomic_cas_u32() but ensures ACQUIRE-and-RELEASE
+ * memory ordering on success. Memory ordering is RELAXED on failure.
+ *
+ * @param atom Pointer to atomic variable
+ * @param[in,out] old_val Pointer to the old value of the atomic variable.
+ * Operation updates this value on failure.
+ * @param new_val New value to be written into the atomic variable
+ *
+ * @return 0 on failure, !0 on success
+ */
+int odp_atomic_cas_acq_rel_u32(odp_atomic_u32_t *atom, uint32_t *old_val,
+ uint32_t new_val);
+
+/**
* Atomic operations
*
* Atomic operations listed in a bit field structure.
--
2.6.3
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