Add functionality to test, set, clear, and assign the value to
individual bits in 32-bit or 64-bit words.
These functions have no implications on memory ordering, atomicity and
does not use volatile and thus does not prevent any compiler
optimizations.
RFC v4:
* Add rte_bit_flip() which, believe it or not, flips the value of a bit.
* Mark macro-generated private functions as experimental.
* Use macros to generate *assign*() functions.
RFC v3:
* Work around lack of C++ support for _Generic (Tyler Retzlaff).
* Fix ','-related checkpatch warnings.
Signed-off-by: Mattias Rönnblom <mattias.ronnb...@ericsson.com>
Acked-by: Morten Brørup <m...@smartsharesystems.com>
Acked-by: Tyler Retzlaff <roret...@linux.microsoft.com>
---
lib/eal/include/rte_bitops.h | 257 ++++++++++++++++++++++++++++++++++-
1 file changed, 255 insertions(+), 2 deletions(-)
diff --git a/lib/eal/include/rte_bitops.h b/lib/eal/include/rte_bitops.h
index 449565eeae..9d426f1602 100644
--- a/lib/eal/include/rte_bitops.h
+++ b/lib/eal/include/rte_bitops.h
@@ -2,6 +2,7 @@
* Copyright(c) 2020 Arm Limited
* Copyright(c) 2010-2019 Intel Corporation
* Copyright(c) 2023 Microsoft Corporation
+ * Copyright(c) 2024 Ericsson AB
*/
#ifndef _RTE_BITOPS_H_
@@ -11,12 +12,14 @@
* @file
* Bit Operations
*
- * This file defines a family of APIs for bit operations
- * without enforcing memory ordering.
+ * This file provides functionality for low-level, single-word
+ * arithmetic and bit-level operations, such as counting or
+ * setting individual bits.
*/
#include <stdint.h>
+#include <rte_compat.h>
#include <rte_debug.h>
#ifdef __cplusplus
@@ -105,6 +108,194 @@ extern "C" {
#define RTE_FIELD_GET64(mask, reg) \
((typeof(mask))(((reg) & (mask)) >> rte_ctz64(mask)))
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Test bit in word.
+ *
+ * Generic selection macro to 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 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_test(addr, nr) \
+ _Generic((addr), \
+ uint32_t *: __rte_bit_test32, \
+ uint64_t *: __rte_bit_test64)(addr, nr)
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Set bit in word.
+ *
+ * Generic selection macro to set 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 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_set(addr, nr) \
+ _Generic((addr), \
+ uint32_t *: __rte_bit_set32, \
+ uint64_t *: __rte_bit_set64)(addr, nr)
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Clear bit in word.
+ *
+ * Generic selection macro to clear 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 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_clear(addr, nr) \
+ _Generic((addr), \
+ uint32_t *: __rte_bit_clear32, \
+ uint64_t *: __rte_bit_clear64)(addr, nr)
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Assign a value to a bit in word.
+ *
+ * Generic selection macro to assign a value to 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 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_assign(addr, nr, value)
\
+ _Generic((addr), \
+ uint32_t *: __rte_bit_assign32, \
+ uint64_t *: __rte_bit_assign64)(addr, nr, value)
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Flip a bit in word.
+ *
+ * Generic selection macro to change the value of a bit to '0' if '1'
+ * or '1' if '0' in a 32-bit or 64-bit word. The type of operation
+ * depends on the type of the @c addr parameter.
+ *
+ * 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_flip(addr, nr) \
+ _Generic((addr), \
+ uint32_t *: __rte_bit_flip32, \
+ uint64_t *: __rte_bit_flip64)(addr, nr)
+
+#define __RTE_GEN_BIT_TEST(family, fun, qualifier, size) \
+ __rte_experimental \
+ static inline bool \
+ __rte_bit_ ## family ## fun ## size(const qualifier uint ## size ## _t
*addr, \
+ unsigned int nr) \
+ { \
+ RTE_ASSERT(nr < size); \
+ \
+ uint ## size ## _t mask = (uint ## size ## _t)1 << nr; \
+ return *addr & mask; \
+ }
+
+#define __RTE_GEN_BIT_SET(family, fun, qualifier, size)
\
+ __rte_experimental \
+ static inline void \
+ __rte_bit_ ## family ## fun ## size(qualifier uint ## size ## _t *addr,
\
+ unsigned int nr) \
+ { \
+ RTE_ASSERT(nr < size); \
+ \
+ uint ## size ## _t mask = (uint ## size ## _t)1 << nr; \
+ *addr |= mask; \
+ } \
+
+#define __RTE_GEN_BIT_CLEAR(family, fun, qualifier, size) \
+ __rte_experimental \
+ static inline void \
+ __rte_bit_ ## family ## fun ## size(qualifier uint ## size ## _t *addr,
\
+ unsigned int nr) \
+ { \
+ RTE_ASSERT(nr < size); \
+ \
+ uint ## size ## _t mask = ~((uint ## size ## _t)1 << nr); \
+ (*addr) &= mask; \
+ } \
+
+#define __RTE_GEN_BIT_ASSIGN(family, fun, qualifier, size) \
+ __rte_experimental \
+ static inline void \
+ __rte_bit_ ## family ## fun ## size(qualifier uint ## size ## _t *addr,
\
+ unsigned int nr, bool value) \
+ { \
+ if (value) \
+ __rte_bit_ ## family ## set ## size(addr, nr); \
+ else \
+ __rte_bit_ ## family ## clear ## size(addr, nr); \
+ }
+
+#define __RTE_GEN_BIT_FLIP(family, fun, qualifier, size) \
+ __rte_experimental \
+ static inline void \
+ __rte_bit_ ## family ## fun ## size(qualifier uint ## size ## _t *addr,
\
+ unsigned int nr) \
+ { \
+ bool value; \
+ \
+ value = __rte_bit_ ## family ## test ## size(addr, nr); \
+ __rte_bit_ ## family ## assign ## size(addr, nr, !value); \
+ }
+
+__RTE_GEN_BIT_TEST(, test,, 32)
+__RTE_GEN_BIT_SET(, set,, 32)
+__RTE_GEN_BIT_CLEAR(, clear,, 32)
+__RTE_GEN_BIT_ASSIGN(, assign,, 32)
+__RTE_GEN_BIT_FLIP(, flip,, 32)
+
+__RTE_GEN_BIT_TEST(, test,, 64)
+__RTE_GEN_BIT_SET(, set,, 64)
+__RTE_GEN_BIT_CLEAR(, clear,, 64)
+__RTE_GEN_BIT_ASSIGN(, assign,, 64)
+__RTE_GEN_BIT_FLIP(, flip,, 64)
+
/*------------------------ 32-bit relaxed operations ------------------------*/
/**
@@ -787,6 +978,68 @@ rte_log2_u64(uint64_t v)
#ifdef __cplusplus
}
+
+/*
+ * Since C++ doesn't support generic selection (i.e., _Generic),
+ * function overloading is used instead. Such functions must be
+ * defined outside 'extern "C"' to be accepted by the compiler.
+ */
+
+#undef rte_bit_test
+#undef rte_bit_set
+#undef rte_bit_clear
+#undef rte_bit_assign
+#undef rte_bit_flip
+
+#define __RTE_BIT_OVERLOAD_SZ_2(fun, qualifier, size, arg1_type, arg1_name) \
+ static inline void \
+ rte_bit_ ## fun(qualifier uint ## size ## _t *addr, \
+ arg1_type arg1_name) \
+ { \
+ __rte_bit_ ## fun ## size(addr, arg1_name); \
+ }
+
+#define __RTE_BIT_OVERLOAD_2(fun, qualifier, arg1_type, arg1_name) \
+ __RTE_BIT_OVERLOAD_SZ_2(fun, qualifier, 32, arg1_type, arg1_name) \
+ __RTE_BIT_OVERLOAD_SZ_2(fun, qualifier, 64, arg1_type, arg1_name)
+
+#define __RTE_BIT_OVERLOAD_SZ_2R(fun, qualifier, size, ret_type, arg1_type, \
+ arg1_name) \
+ static inline ret_type \
+ rte_bit_ ## fun(qualifier uint ## size ## _t *addr, \
+ arg1_type arg1_name) \
+ { \
+ return __rte_bit_ ## fun ## size(addr, arg1_name); \
+ }
+
+#define __RTE_BIT_OVERLOAD_2R(fun, qualifier, ret_type, arg1_type, arg1_name) \
+ __RTE_BIT_OVERLOAD_SZ_2R(fun, qualifier, 32, ret_type, arg1_type, \
+ arg1_name) \
+ __RTE_BIT_OVERLOAD_SZ_2R(fun, qualifier, 64, ret_type, arg1_type, \
+ arg1_name)
+
+#define __RTE_BIT_OVERLOAD_SZ_3(fun, qualifier, size, arg1_type, arg1_name, \
+ arg2_type, arg2_name) \
+ static inline void \
+ rte_bit_ ## fun(uint ## size ## _t *addr, arg1_type arg1_name, \
+ arg2_type arg2_name) \
+ { \
+ __rte_bit_ ## fun ## size(addr, arg1_name, arg2_name); \
+ }
+
+#define __RTE_BIT_OVERLOAD_3(fun, qualifier, arg1_type, arg1_name, arg2_type, \
+ arg2_name) \
+ __RTE_BIT_OVERLOAD_SZ_3(fun, qualifier, 32, arg1_type, arg1_name, \
+ arg2_type, arg2_name) \
+ __RTE_BIT_OVERLOAD_SZ_3(fun, qualifier, 64, arg1_type, arg1_name, \
+ arg2_type, arg2_name)
+
+__RTE_BIT_OVERLOAD_2R(test, const, bool, unsigned int, nr)
+__RTE_BIT_OVERLOAD_2(set,, unsigned int, nr)
+__RTE_BIT_OVERLOAD_2(clear,, unsigned int, nr)
+__RTE_BIT_OVERLOAD_3(assign,, unsigned int, nr, bool, value)
+__RTE_BIT_OVERLOAD_2(flip,, unsigned int, nr)
+
#endif
#endif /* _RTE_BITOPS_H_ */
--
2.34.1
