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139 lines
4.4 KiB
C
139 lines
4.4 KiB
C
/* ----------------------------------------------------------------------------
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* ATMEL Microcontroller Software Support
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* ----------------------------------------------------------------------------
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* Copyright (c) 2011, Atmel Corporation
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* - Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the disclaimer below.
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*
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* Atmel's name may not be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
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* DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
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* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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* ----------------------------------------------------------------------------
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*/
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#ifndef _INTMATH_H_
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#define _INTMATH_H_
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/**
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* \brief Compute the absolute value of the difference between two integers.
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* \param a The first integer.
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* \param b The second integer.
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* \return The absolute difference.
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*/
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#define ABS_DIFF(a,b) ((a) < (b) ? (b) - (a) : (a) - (b))
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/**
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* \brief Compute the ceiling of the quotient of two integers.
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* \param n The dividend.
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* \param d The divisor.
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* \note The two integers shall have the same sign.
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* \return The ceiling of the quotient.
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*/
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#define CEIL_INT_DIV(n,d) (((n) + (d) - 1) / (d))
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/*------------------------------------------------------------------------------
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* Exported functions
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*------------------------------------------------------------------------------*/
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#include <stdint.h>
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/** Check possible extensions of the C library being used, and find out if
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* visible ones provide bit-string functions, including ffs() and fls().
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* These functions are not part of ANSI C.
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* Newlib 3.0.0, notably, provides BSD extensions that include fls().
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*/
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#if defined(__NEWLIB__) && \
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(__NEWLIB__ > 1 || (__NEWLIB__ == 1 && __NEWLIB_MINOR__ > 18))
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#include <strings.h>
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#if defined(_DEFAULT_SOURCE) && (__NEWLIB__ > 2)
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#define HAVE_BSD_FLS
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#endif
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#endif /* __NEWLIB__ */
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/**
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* Returns the minimum value between two integers.
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* \param a First integer to compare
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* \param b Second integer to compare
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*/
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static inline uint32_t min_u32(uint32_t a, uint32_t b)
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{
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return a < b ? a : b;
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}
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/**
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* Returns the maximum value between two integers.
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* \param a First integer to compare
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* \param b Second integer to compare
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*/
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static inline uint32_t max_u32(uint32_t a, uint32_t b)
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{
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return a > b ? a : b;
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}
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/**
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* Returns the absolute value of an integer.
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* \param value Integer value
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*/
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static inline uint32_t abs_u32(int32_t value)
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{
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return value > 0 ? value : -value;
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}
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/**
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* Computes and returns x to the power of y.
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* \param x Value
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* \param y Power
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*/
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static inline uint32_t power_u32(uint32_t x, uint32_t y)
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{
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uint32_t result = 1;
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while (y > 0) {
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result *= x;
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y--;
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}
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return result;
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}
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/** ISO/IEC 14882:2003(E) - 5.6 Multiplicative operators:
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* The binary / operator yields the quotient, and the binary % operator yields the remainder
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* from the division of the first expression by the second.
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* If the second operand of / or % is zero the behavior is undefined; otherwise (a/b)*b + a%b is equal to a.
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* If both operands are nonnegative then the remainder is nonnegative;
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* if not, the sign of the remainder is implementation-defined 74).
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*/
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static inline int fixed_mod(int a, int b)
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{
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int rem = a % b;
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while (rem < 0)
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rem += b;
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return rem;
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}
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#ifndef HAVE_BSD_FLS
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/**
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* Find last bit set in a word
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* \param value Integer value
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* \return 1-indexed position of the most significant bit set; 0 if none
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*/
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extern int fls(int value);
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#endif
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#endif /* _INTMATH_H_ */
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