eal: introduce rte version of fls

[dpdk.git] / lib / librte_eal / common / include / rte_common.h

diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
index 69e5ed1..87f0f63 100644 (file)
--- a/lib/librte_eal/common/include/rte_common.h
+++ b/lib/librte_eal/common/include/rte_common.h
@@ -68,6 +68,11 @@ typedef uint16_t unaligned_uint16_t;
 /******* Macro to mark functions and fields scheduled for removal *****/
 #define __rte_deprecated       __attribute__((__deprecated__))
 
+/**
+ * Mark a function or variable to a weak reference.
+ */
+#define __rte_weak __attribute__((__weak__))
+
 /*********** Macros to eliminate unused variable warnings ********/
 
 /**
@@ -83,6 +88,7 @@ typedef uint16_t unaligned_uint16_t;
 
 #define RTE_PRIORITY_LOG 101
 #define RTE_PRIORITY_BUS 110
+#define RTE_PRIORITY_CLASS 120
 #define RTE_PRIORITY_LAST 65535
 
 #define RTE_PRIO(prio) \
@@ -111,6 +117,29 @@ static void __attribute__((constructor(RTE_PRIO(prio)), used)) func(void)
 #define RTE_INIT(func) \
        RTE_INIT_PRIO(func, LAST)
 
+/**
+ * Run after main() with low priority.
+ *
+ * @param func
+ *   Destructor function name.
+ * @param prio
+ *   Priority number must be above 100.
+ *   Lowest number is the last to run.
+ */
+#define RTE_FINI_PRIO(func, prio) \
+static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void)
+
+/**
+ * Run after main() with high priority.
+ *
+ * The destructor will be run *before* prioritized destructors.
+ *
+ * @param func
+ *   Destructor function name.
+ */
+#define RTE_FINI(func) \
+       RTE_FINI_PRIO(func, LAST)
+
 /**
  * Force a function to be inlined
  */
@@ -124,7 +153,7 @@ static void __attribute__((constructor(RTE_PRIO(prio)), used)) func(void)
 /*********** Macros for pointer arithmetic ********/
 
 /**
- * add a byte-value offset from a pointer
+ * add a byte-value offset to a pointer
  */
 #define RTE_PTR_ADD(ptr, x) ((void*)((uintptr_t)(ptr) + (x)))
 
@@ -140,6 +169,12 @@ static void __attribute__((constructor(RTE_PRIO(prio)), used)) func(void)
  */
 #define RTE_PTR_DIFF(ptr1, ptr2) ((uintptr_t)(ptr1) - (uintptr_t)(ptr2))
 
+/**
+ * Workaround to cast a const field of a structure to non-const type.
+ */
+#define RTE_CAST_FIELD(var, field, type) \
+       (*(type *)((uintptr_t)(var) + offsetof(typeof(*(var)), field)))
+
 /*********** Macros/static functions for doing alignment ********/
 
 
@@ -293,6 +328,11 @@ rte_combine64ms1b(register uint64_t v)
 
 /*********** Macros to work with powers of 2 ********/
 
+/**
+ * Macro to return 1 if n is a power of 2, 0 otherwise
+ */
+#define RTE_IS_POWER_OF_2(n) ((n) && !(((n) - 1) & (n)))
+
 /**
  * Returns true if n is a power of 2
  * @param n
@@ -413,7 +453,7 @@ rte_align64prevpow2(uint64_t v)
 static inline uint32_t
 rte_bsf32(uint32_t v)
 {
-       return __builtin_ctz(v);
+       return (uint32_t)__builtin_ctz(v);
 }
 
 /**
@@ -433,6 +473,25 @@ rte_log2_u32(uint32_t v)
        return rte_bsf32(v);
 }
 
+
+/**
+ * Return the last (most-significant) bit set.
+ *
+ * @note The last (most significant) bit is at position 32.
+ * @note rte_fls_u32(0) = 0, rte_fls_u32(1) = 1, rte_fls_u32(0x80000000) = 32
+ *
+ * @param x
+ *     The input parameter.
+ * @return
+ *     The last (most-significant) bit set, or 0 if the input is 0.
+ */
+static inline int
+rte_fls_u32(uint32_t x)
+{
+       return (x == 0) ? 0 : 32 - __builtin_clz(x);
+}
+
+
 #ifndef offsetof
 /** Return the offset of a field in a structure. */
 #define offsetof(TYPE, MEMBER)  __builtin_offsetof (TYPE, MEMBER)