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78 lines
1.7 KiB
C
78 lines
1.7 KiB
C
/*
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* Copyright (C) 2017 Freie Universität Berlin
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @defgroup sys_bcd Binary coded decimal
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* @ingroup sys
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* @brief Library to de- and encode binary coded decimals
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* @{
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*
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* @file
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* @brief BCD definitions
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*
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* @author Martine Lenders <m.lenders@fu-berlin.de>
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*/
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#ifndef BCD_H
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#define BCD_H
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#include <stddef.h>
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#include <stdint.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @brief Converts a byte to a binary coded decimal
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*
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* @param[in] byte A byte
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*
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* @return A binary coded decimal (4 MSB = 10s, 4 LSB = 1s)
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*/
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static inline uint8_t bcd_from_byte(uint8_t byte)
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{
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/* ((byte / 10) << 4) | (byte % 10) */
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return byte + (6 * (byte / 10));
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}
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/**
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* @brief Converts a binary coded decimal to a byte
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*
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* @param[in] bcd A binary coded decimal (4 MSB = 10, 4 LSB = 1s)
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*
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* @return A byte
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*/
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static inline uint8_t bcd_to_byte(uint8_t bcd)
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{
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/* == (10 * (bcd >> 4)) + (bcd & 0xf) */
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return bcd - (6 * (bcd >> 4));
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}
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/**
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* @brief Convert a decimal value into a BCD buffer.
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* (This looks like the decimal integer value when printed as hex)
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*
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* This will e.g. turn the value 123 -> 0x123 (decimal: 291)
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*
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* @param[in] val Decimal value to print
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* @param[out] dst Destination buffer
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* @param[in] len Size of the destination buffer
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*
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* @return number of bytes written
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* @return -ENOBUFS if @p dst is not large enough
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* In that case the state of @p dst is undefined.
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*/
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int bcd_buf_from_u32(uint32_t val, void *dst, size_t len);
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#ifdef __cplusplus
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}
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#endif
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#endif /* BCD_H */
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/** @} */
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