root / freemodbus / modbus / functions / mbutils.c @ 20e5429c
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1 | 20e5429c | Tom Mullins | /*
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2 | * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
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3 | * Copyright (c) 2006 Christian Walter <wolti@sil.at>
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4 | * All rights reserved.
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5 | *
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6 | * Redistribution and use in source and binary forms, with or without
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7 | * modification, are permitted provided that the following conditions
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8 | * are met:
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9 | * 1. Redistributions of source code must retain the above copyright
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10 | * notice, this list of conditions and the following disclaimer.
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11 | * 2. Redistributions in binary form must reproduce the above copyright
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12 | * notice, this list of conditions and the following disclaimer in the
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13 | * documentation and/or other materials provided with the distribution.
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14 | * 3. The name of the author may not be used to endorse or promote products
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15 | * derived from this software without specific prior written permission.
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16 | *
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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27 | *
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28 | * File: $Id: mbutils.c,v 1.6 2007/02/18 23:49:07 wolti Exp $
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29 | */
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30 | |||
31 | /* ----------------------- System includes ----------------------------------*/
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32 | #include "stdlib.h" |
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33 | #include "string.h" |
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34 | |||
35 | /* ----------------------- Platform includes --------------------------------*/
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36 | #include "port.h" |
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37 | |||
38 | /* ----------------------- Modbus includes ----------------------------------*/
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39 | #include "mb.h" |
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40 | #include "mbproto.h" |
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41 | |||
42 | /* ----------------------- Defines ------------------------------------------*/
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43 | #define BITS_UCHAR 8U |
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44 | |||
45 | /* ----------------------- Start implementation -----------------------------*/
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46 | void
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47 | xMBUtilSetBits( UCHAR * ucByteBuf, USHORT usBitOffset, UCHAR ucNBits, |
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48 | UCHAR ucValue ) |
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49 | { |
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50 | USHORT usWordBuf; |
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51 | USHORT usMask; |
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52 | USHORT usByteOffset; |
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53 | USHORT usNPreBits; |
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54 | USHORT usValue = ucValue; |
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55 | |||
56 | assert( ucNBits <= 8 );
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57 | assert( ( size_t )BITS_UCHAR == sizeof( UCHAR ) * 8 ); |
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58 | |||
59 | /* Calculate byte offset for first byte containing the bit values starting
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60 | * at usBitOffset. */
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61 | usByteOffset = ( USHORT )( ( usBitOffset ) / BITS_UCHAR ); |
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62 | |||
63 | /* How many bits precede our bits to set. */
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64 | usNPreBits = ( USHORT )( usBitOffset - usByteOffset * BITS_UCHAR ); |
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65 | |||
66 | /* Move bit field into position over bits to set */
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67 | usValue <<= usNPreBits; |
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68 | |||
69 | /* Prepare a mask for setting the new bits. */
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70 | usMask = ( USHORT )( ( 1 << ( USHORT ) ucNBits ) - 1 ); |
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71 | usMask <<= usBitOffset - usByteOffset * BITS_UCHAR; |
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72 | |||
73 | /* copy bits into temporary storage. */
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74 | usWordBuf = ucByteBuf[usByteOffset]; |
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75 | usWordBuf |= ucByteBuf[usByteOffset + 1] << BITS_UCHAR;
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76 | |||
77 | /* Zero out bit field bits and then or value bits into them. */
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78 | usWordBuf = ( USHORT )( ( usWordBuf & ( ~usMask ) ) | usValue ); |
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79 | |||
80 | /* move bits back into storage */
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81 | ucByteBuf[usByteOffset] = ( UCHAR )( usWordBuf & 0xFF );
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82 | ucByteBuf[usByteOffset + 1] = ( UCHAR )( usWordBuf >> BITS_UCHAR );
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83 | } |
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84 | |||
85 | UCHAR |
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86 | xMBUtilGetBits( UCHAR * ucByteBuf, USHORT usBitOffset, UCHAR ucNBits ) |
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87 | { |
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88 | USHORT usWordBuf; |
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89 | USHORT usMask; |
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90 | USHORT usByteOffset; |
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91 | USHORT usNPreBits; |
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92 | |||
93 | /* Calculate byte offset for first byte containing the bit values starting
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94 | * at usBitOffset. */
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95 | usByteOffset = ( USHORT )( ( usBitOffset ) / BITS_UCHAR ); |
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96 | |||
97 | /* How many bits precede our bits to set. */
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98 | usNPreBits = ( USHORT )( usBitOffset - usByteOffset * BITS_UCHAR ); |
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99 | |||
100 | /* Prepare a mask for setting the new bits. */
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101 | usMask = ( USHORT )( ( 1 << ( USHORT ) ucNBits ) - 1 ); |
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102 | |||
103 | /* copy bits into temporary storage. */
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104 | usWordBuf = ucByteBuf[usByteOffset]; |
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105 | usWordBuf |= ucByteBuf[usByteOffset + 1] << BITS_UCHAR;
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106 | |||
107 | /* throw away unneeded bits. */
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108 | usWordBuf >>= usNPreBits; |
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109 | |||
110 | /* mask away bits above the requested bitfield. */
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111 | usWordBuf &= usMask; |
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112 | |||
113 | return ( UCHAR ) usWordBuf;
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114 | } |
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115 | |||
116 | eMBException |
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117 | prveMBError2Exception( eMBErrorCode eErrorCode ) |
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118 | { |
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119 | eMBException eStatus; |
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120 | |||
121 | switch ( eErrorCode )
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122 | { |
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123 | case MB_ENOERR:
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124 | eStatus = MB_EX_NONE; |
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125 | break;
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126 | |||
127 | case MB_ENOREG:
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128 | eStatus = MB_EX_ILLEGAL_DATA_ADDRESS; |
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129 | break;
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130 | |||
131 | case MB_ETIMEDOUT:
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132 | eStatus = MB_EX_SLAVE_BUSY; |
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133 | break;
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134 | |||
135 | default:
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136 | eStatus = MB_EX_SLAVE_DEVICE_FAILURE; |
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137 | break;
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138 | } |
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139 | |||
140 | return eStatus;
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141 | } |