Add macros for once-type bit operations operating on both 32-bit and
64-bit words by means of C11 generic selection.
Signed-off-by: Mattias Rönnblom <mattias.ronnb...@ericsson.com>
---
lib/eal/include/rte_bitops.h | 101 +++++++++++++++++++++++++++++++++++
1 file changed, 101 insertions(+)
diff --git a/lib/eal/include/rte_bitops.h b/lib/eal/include/rte_bitops.h
index 3118c51748..450334c751 100644
--- a/lib/eal/include/rte_bitops.h
+++ b/lib/eal/include/rte_bitops.h
@@ -188,6 +188,107 @@ extern "C" {
uint32_t *: rte_bit_assign32, \
uint64_t *: rte_bit_assign64)(addr, nr, value)
+/**
+ * Test exactly once if a particular bit in a word is set.
+ *
+ * Generic selection macro to exactly once test the value of a bit in
+ * a 32-bit or 64-bit word. The type of operation depends on the type
+ * of the @c addr parameter.
+ *
+ * This macro is guaranteed to result in exactly one memory load. See
+ * rte_bit_once_test32() for more information and uses cases for the
+ * "once" class of functions.
+ *
+ * rte_bit_once_test() does give any guarantees in regards to memory
+ * ordering or atomicity.
+ *
+ * @param addr
+ * A pointer to the word to query.
+ * @param nr
+ * The index of the bit.
+ * @return
+ * Returns true if the bit is set, and false otherwise.
+ */
+
+#define rte_bit_once_test(addr, nr) \
+ _Generic((addr), \
+ uint32_t *: rte_bit_once_test32, \
+ uint64_t *: rte_bit_once_test64)(addr, nr)
+
+/**
+ * Set bit in word exactly once.
+ *
+ * Set bit specified by @c nr in the word pointed to by @c addr to '1'
+ * exactly once.
+ *
+ * This function is guaranteed to result in exactly one memory load
+ * and exactly one memory store, *or* an atomic bit set operation.
+ *
+ * See rte_bit_test_once32() for more information and uses cases for
+ * the "once" class of functions.
+ *
+ * This macro does not give any guarantees in regards to memory
+ * ordering or atomicity.
+ *
+ * @param addr
+ * A pointer to the word to modify.
+ * @param nr
+ * The index of the bit.
+ */
+#define rte_bit_once_set(addr, nr) \
+ _Generic((addr), \
+ uint32_t *: rte_bit_once_set32, \
+ uint64_t *: rte_bit_once_set64)(addr, nr)
+
+/**
+ * Clear bit in word exactly once.
+ *
+ * Set bit specified by @c nr in the word pointed to by @c addr to '0'
+ * exactly once.
+ *
+ * This function is guaranteed to result in exactly one memory load
+ * and exactly one memory store, *or* an atomic bit clear operation.
+ *
+ * See rte_bit_test_once32() for more information and uses cases for
+ * the "once" class of functions.
+ *
+ * This macro does not give any guarantees in regards to memory
+ * ordering or atomicity.
+ *
+ * @param addr
+ * A pointer to the word to modify.
+ * @param nr
+ * The index of the bit.
+ */
+#define rte_bit_once_clear(addr, nr) \
+ _Generic((addr), \
+ uint32_t *: rte_bit_once_clear32, \
+ uint64_t *: rte_bit_once_clear64)(addr, nr)
+
+/**
+ * Assign a value to bit in a word exactly once.
+ *
+ * Set bit specified by @c nr in the word pointed to by @c addr to the
+ * value indicated by @c value exactly once.
+ *
+ * This function is guaranteed to result in exactly one memory load
+ * and exactly one memory store, *or* an atomic bit clear operation.
+ *
+ * This function does not give any guarantees in regards to memory
+ * ordering or atomicity.
+ *
+ * @param addr
+ * A pointer to the word to modify.
+ * @param nr
+ * The index of the bit.
+ * @param value
+ * The new value of the bit - true for '1', or false for '0'.
+ */
+#define rte_bit_once_assign(addr, nr, value) \
+ _Generic((addr), \
+ uint32_t *: rte_bit_once_assign32, \
+ uint64_t *: rte_bit_once_assign64)(addr, nr, value)
+
/**
* Test if a particular bit in a 32-bit word is set.
*
--
2.34.1
