diff mbox series

[3/6] common: add missing implementations

Message ID e45a0cd3276537ce1d52b937bd2d08db9c4a348e.1544550999.git.anatoly.burakov@intel.com (mailing list archive)
State Superseded, archived
Delegated to: Thomas Monjalon
Headers show
Series [1/6] bitmap: remove deprecated bsf64 function | expand

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/Intel-compilation success Compilation OK

Commit Message

Burakov, Anatoly Dec. 11, 2018, 5:57 p.m. UTC
Implement missing functions for 32-bit safe bsf, as well as 64-bit
fls and log2.

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
---

Notes:
    v4:
    - Fixed to use proper rte_bsf64
    
    v3:
    - Added clarification that pos is not checked

 lib/librte_eal/common/include/rte_common.h | 62 +++++++++++++++++++++-
 1 file changed, 61 insertions(+), 1 deletion(-)

Comments

Thomas Monjalon Dec. 20, 2018, 9:09 a.m. UTC | #1
11/12/2018 18:57, Anatoly Burakov:
> Implement missing functions for 32-bit safe bsf, as well as 64-bit
> fls and log2.

It would be better to make 3 patches, for each function,
updating eal_memalloc.c, testpmd and tests at the same time.
Burakov, Anatoly Dec. 20, 2018, 9:16 a.m. UTC | #2
On 20-Dec-18 9:09 AM, Thomas Monjalon wrote:
> 11/12/2018 18:57, Anatoly Burakov:
>> Implement missing functions for 32-bit safe bsf, as well as 64-bit
>> fls and log2.
> 
> It would be better to make 3 patches, for each function,
> updating eal_memalloc.c, testpmd and tests at the same time.
> 

Sure, will respin.
diff mbox series

Patch

diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
index 2735dcca7..4bbfef7a0 100644
--- a/lib/librte_eal/common/include/rte_common.h
+++ b/lib/librte_eal/common/include/rte_common.h
@@ -447,6 +447,30 @@  rte_bsf32(uint32_t v)
 	return (uint32_t)__builtin_ctz(v);
 }
 
+/**
+ * Searches the input parameter for the least significant set bit
+ * (starting from zero). Safe version (checks for input parameter being zero).
+ *
+ * @warning ``pos`` must be a valid pointer. It is not checked!
+ *
+ * @param v
+ *     The input parameter.
+ * @param pos
+ *     If ``v`` was not 0, this value will contain position of least significant
+ *     bit within the input parameter.
+ * @return
+ *     Returns 0 if ``v`` was 0, otherwise returns 1.
+ */
+static inline int
+rte_bsf32_safe(uint64_t v, uint32_t *pos)
+{
+	if (v == 0)
+		return 0;
+
+	*pos = rte_bsf32(v);
+	return 1;
+}
+
 /**
  * Return the rounded-up log2 of a integer.
  *
@@ -464,7 +488,6 @@  rte_log2_u32(uint32_t v)
 	return rte_bsf32(v);
 }
 
-
 /**
  * Return the last (most-significant) bit set.
  *
@@ -523,6 +546,43 @@  rte_bsf64_safe(uint64_t v, uint32_t *pos)
 	return 1;
 }
 
+/**
+ * Return the last (most-significant) bit set.
+ *
+ * @note The last (most significant) bit is at position 64.
+ * @note rte_fls_u64(0) = 0, rte_fls_u64(1) = 1,
+ *       rte_fls_u64(0x8000000000000000) = 64
+ *
+ * @param x
+ *     The input parameter.
+ * @return
+ *     The last (most-significant) bit set, or 0 if the input is 0.
+ */
+static inline int
+rte_fls_u64(uint64_t x)
+{
+	return (x == 0) ? 0 : 64 - __builtin_clzll(x);
+}
+
+/**
+ * Return the rounded-up log2 of a 64-bit integer.
+ *
+ * @param v
+ *     The input parameter.
+ * @return
+ *     The rounded-up log2 of the input, or 0 if the input is 0.
+ */
+static inline uint32_t
+rte_log2_u64(uint64_t v)
+{
+	if (v == 0)
+		return 0;
+	v = rte_align64pow2(v);
+	/* we checked for v being 0 already, so no undefined behavior */
+	return rte_bsf64(v);
+}
+
+
 #ifndef offsetof
 /** Return the offset of a field in a structure. */
 #define offsetof(TYPE, MEMBER)  __builtin_offsetof (TYPE, MEMBER)