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mbutils.cpp
00001 /* 00002 * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU. 00003 * Copyright (c) 2006 Christian Walter <wolti@sil.at> 00004 * All rights reserved. 00005 * 00006 * Redistribution and use in source and binary forms, with or without 00007 * modification, are permitted provided that the following conditions 00008 * are met: 00009 * 1. Redistributions of source code must retain the above copyright 00010 * notice, this list of conditions and the following disclaimer. 00011 * 2. Redistributions in binary form must reproduce the above copyright 00012 * notice, this list of conditions and the following disclaimer in the 00013 * documentation and/or other materials provided with the distribution. 00014 * 3. The name of the author may not be used to endorse or promote products 00015 * derived from this software without specific prior written permission. 00016 * 00017 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 00018 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 00019 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 00020 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 00021 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 00022 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 00023 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 00024 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 00025 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 00026 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 00027 * 00028 * File: $Id: mbutils.c,v 1.6 2007/02/18 23:49:07 wolti Exp $ 00029 */ 00030 00031 /* ----------------------- System includes ----------------------------------*/ 00032 #include "stdlib.h" 00033 #include "string.h" 00034 00035 /* ----------------------- Platform includes --------------------------------*/ 00036 #include "port.h" 00037 00038 /* ----------------------- Modbus includes ----------------------------------*/ 00039 #include "mb.h" 00040 #include "mbproto.h" 00041 00042 /* ----------------------- Defines ------------------------------------------*/ 00043 #define BITS_UCHAR 8U 00044 00045 /* ----------------------- Start implementation -----------------------------*/ 00046 void 00047 xMBUtilSetBits( UCHAR * ucByteBuf, USHORT usBitOffset, UCHAR ucNBits, 00048 UCHAR ucValue ) 00049 { 00050 USHORT usWordBuf; 00051 USHORT usMask; 00052 USHORT usByteOffset; 00053 USHORT usNPreBits; 00054 USHORT usValue = ucValue; 00055 00056 assert( ucNBits <= 8 ); 00057 assert( ( size_t )BITS_UCHAR == sizeof( UCHAR ) * 8 ); 00058 00059 /* Calculate byte offset for first byte containing the bit values starting 00060 * at usBitOffset. */ 00061 usByteOffset = ( USHORT )( ( usBitOffset ) / BITS_UCHAR ); 00062 00063 /* How many bits precede our bits to set. */ 00064 usNPreBits = ( USHORT )( usBitOffset - usByteOffset * BITS_UCHAR ); 00065 00066 /* Move bit field into position over bits to set */ 00067 usValue <<= usNPreBits; 00068 00069 /* Prepare a mask for setting the new bits. */ 00070 usMask = ( USHORT )( ( 1 << ( USHORT ) ucNBits ) - 1 ); 00071 usMask <<= usBitOffset - usByteOffset * BITS_UCHAR; 00072 00073 /* copy bits into temporary storage. */ 00074 usWordBuf = ucByteBuf[usByteOffset]; 00075 usWordBuf |= ucByteBuf[usByteOffset + 1] << BITS_UCHAR; 00076 00077 /* Zero out bit field bits and then or value bits into them. */ 00078 usWordBuf = ( USHORT )( ( usWordBuf & ( ~usMask ) ) | usValue ); 00079 00080 /* move bits back into storage */ 00081 ucByteBuf[usByteOffset] = ( UCHAR )( usWordBuf & 0xFF ); 00082 ucByteBuf[usByteOffset + 1] = ( UCHAR )( usWordBuf >> BITS_UCHAR ); 00083 } 00084 00085 UCHAR 00086 xMBUtilGetBits( UCHAR * ucByteBuf, USHORT usBitOffset, UCHAR ucNBits ) 00087 { 00088 USHORT usWordBuf; 00089 USHORT usMask; 00090 USHORT usByteOffset; 00091 USHORT usNPreBits; 00092 00093 /* Calculate byte offset for first byte containing the bit values starting 00094 * at usBitOffset. */ 00095 usByteOffset = ( USHORT )( ( usBitOffset ) / BITS_UCHAR ); 00096 00097 /* How many bits precede our bits to set. */ 00098 usNPreBits = ( USHORT )( usBitOffset - usByteOffset * BITS_UCHAR ); 00099 00100 /* Prepare a mask for setting the new bits. */ 00101 usMask = ( USHORT )( ( 1 << ( USHORT ) ucNBits ) - 1 ); 00102 00103 /* copy bits into temporary storage. */ 00104 usWordBuf = ucByteBuf[usByteOffset]; 00105 usWordBuf |= ucByteBuf[usByteOffset + 1] << BITS_UCHAR; 00106 00107 /* throw away unneeded bits. */ 00108 usWordBuf >>= usNPreBits; 00109 00110 /* mask away bits above the requested bitfield. */ 00111 usWordBuf &= usMask; 00112 00113 return ( UCHAR ) usWordBuf; 00114 } 00115 00116 eMBException 00117 prveMBError2Exception( eMBErrorCode eErrorCode ) 00118 { 00119 eMBException eStatus; 00120 00121 switch ( eErrorCode ) 00122 { 00123 case MB_ENOERR : 00124 eStatus = MB_EX_NONE; 00125 break; 00126 00127 case MB_ENOREG : 00128 eStatus = MB_EX_ILLEGAL_DATA_ADDRESS; 00129 break; 00130 00131 case MB_ETIMEDOUT : 00132 eStatus = MB_EX_SLAVE_BUSY; 00133 break; 00134 00135 default: 00136 eStatus = MB_EX_SLAVE_DEVICE_FAILURE; 00137 break; 00138 } 00139 00140 return eStatus; 00141 }
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