73 lines
2.0 KiB
C
73 lines
2.0 KiB
C
/*
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* Copyright (c) 2019 Facebook.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* @file
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* @brief Extra arithmetic and bit manipulation functions.
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*
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* @details This header file provides portable wrapper functions for a number of
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* arithmetic and bit-counting functions that are often provided by compiler
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* builtins. If the compiler does not have an appropriate builtin, a portable C
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* implementation is used instead.
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*/
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#ifndef ZEPHYR_INCLUDE_SYS_MATH_EXTRAS_H_
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#define ZEPHYR_INCLUDE_SYS_MATH_EXTRAS_H_
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#include <zephyr/types.h>
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#include <stdbool.h>
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#include <stddef.h>
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/**
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* @name Unsigned integer addition with overflow detection.
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*
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* These functions compute `a + b` and store the result in `*result`, returning
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* true if the operation overflowed.
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*/
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/**@{*/
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static bool u32_add_overflow(u32_t a, u32_t b, u32_t *result);
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static bool u64_add_overflow(u64_t a, u64_t b, u64_t *result);
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static bool size_add_overflow(size_t a, size_t b, size_t *result);
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/**@}*/
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/**
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* @name Unsigned integer multiplication with overflow detection.
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*
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* These functions compute `a * b` and store the result in `*result`, returning
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* true if the operation overflowed.
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*/
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/**@{*/
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static bool u32_mul_overflow(u32_t a, u32_t b, u32_t *result);
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static bool u64_mul_overflow(u64_t a, u64_t b, u64_t *result);
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static bool size_mul_overflow(size_t a, size_t b, size_t *result);
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/**@}*/
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/**
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* @name Count leading zeros.
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*
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* Count the number of leading zero bits in the bitwise representation of `x`.
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* When `x = 0`, this is the size of `x` in bits.
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*/
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/**@{*/
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static int u32_count_leading_zeros(u32_t x);
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static int u64_count_leading_zeros(u64_t x);
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/**@}*/
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/**
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* @name Count trailing zeros.
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*
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* Count the number of trailing zero bits in the bitwise representation of `x`.
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* When `x = 0`, this is the size of `x` in bits.
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*/
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/**@{*/
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static int u32_count_trailing_zeros(u32_t x);
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static int u64_count_trailing_zeros(u64_t x);
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/**@}*/
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#include <sys/math_extras_impl.h>
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#endif /* ZEPHYR_INCLUDE_SYS_MATH_EXTRAS_H_ */
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