[dpdk-dev] [PATCH 2/6] common: add bsf64 function similar to existing bsf32
Anatoly Burakov
anatoly.burakov at intel.com
Tue Dec 11 18:57:10 CET 2018
Implement a new rte_bsf64 function that is following convention
set by existing rte_bsf32 function. Also, document the change in
release notes.
Signed-off-by: Anatoly Burakov <anatoly.burakov at intel.com>
---
doc/guides/rel_notes/release_19_02.rst | 4 +++-
lib/librte_eal/common/include/rte_common.h | 19 ++++++++++++++++++-
2 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/doc/guides/rel_notes/release_19_02.rst b/doc/guides/rel_notes/release_19_02.rst
index ff81357d4..1d56ad43e 100644
--- a/doc/guides/rel_notes/release_19_02.rst
+++ b/doc/guides/rel_notes/release_19_02.rst
@@ -85,7 +85,9 @@ API Changes
* eal: function ``rte_bsf64`` in ``rte_bitmap.h`` has been renamed to
- ``rte_bsf64_safe`` and moved to ``rte_common.h``.
+ ``rte_bsf64_safe`` and moved to ``rte_common.h``. A new ``rte_bsf64`` function
+ has been added in ``rte_common.h`` that follows convention set by existing
+ ``rte_bsf32`` function.
ABI Changes
diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
index 66cdf60b2..2735dcca7 100644
--- a/lib/librte_eal/common/include/rte_common.h
+++ b/lib/librte_eal/common/include/rte_common.h
@@ -482,6 +482,23 @@ rte_fls_u32(uint32_t x)
return (x == 0) ? 0 : 32 - __builtin_clz(x);
}
+/**
+ * Searches the input parameter for the least significant set bit
+ * (starting from zero).
+ * If a least significant 1 bit is found, its bit index is returned.
+ * If the content of the input parameter is zero, then the content of the return
+ * value is undefined.
+ * @param v
+ * input parameter, should not be zero.
+ * @return
+ * least significant set bit in the input parameter.
+ */
+static inline int
+rte_bsf64(uint64_t v)
+{
+ return (uint32_t)__builtin_ctzll(v);
+}
+
/**
* Searches the input parameter for the least significant set bit
* (starting from zero). Safe version (checks for input parameter being zero).
@@ -502,7 +519,7 @@ rte_bsf64_safe(uint64_t v, uint32_t *pos)
if (v == 0)
return 0;
- *pos = __builtin_ctzll(v);
+ *pos = rte_bsf64(v);
return 1;
}
--
2.17.1
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