1 /* 2 * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU. 3 * Copyright (c) 2006 Christian Walter <[email protected]> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * File: $Id: mbutils.c,v 1.6 2007/02/18 23:49:07 wolti Exp $ 29 */ 30 31 /* ----------------------- System includes ----------------------------------*/ 32 #include "stdlib.h" 33 #include "string.h" 34 35 /* ----------------------- Platform includes --------------------------------*/ 36 #include "port.h" 37 38 /* ----------------------- Modbus includes ----------------------------------*/ 39 #include "mb.h" 40 #include "mbproto.h" 41 42 /* ----------------------- Defines ------------------------------------------*/ 43 #define BITS_UCHAR 8U 44 45 /* ----------------------- Start implementation -----------------------------*/ 46 void 47 xMBUtilSetBits( UCHAR * ucByteBuf, USHORT usBitOffset, UCHAR ucNBits, 48 UCHAR ucValue ) 49 { 50 USHORT usWordBuf; 51 USHORT usMask; 52 USHORT usByteOffset; 53 USHORT usNPreBits; 54 USHORT usValue = ucValue; 55 56 RT_ASSERT( ucNBits <= 8 ); 57 RT_ASSERT( ( size_t )BITS_UCHAR == sizeof( UCHAR ) * 8 ); 58 59 /* Calculate byte offset for first byte containing the bit values starting 60 * at usBitOffset. */ 61 usByteOffset = ( USHORT )( ( usBitOffset ) / BITS_UCHAR ); 62 63 /* How many bits precede our bits to set. */ 64 usNPreBits = ( USHORT )( usBitOffset - usByteOffset * BITS_UCHAR ); 65 66 /* Move bit field into position over bits to set */ 67 usValue <<= usNPreBits; 68 69 /* Prepare a mask for setting the new bits. */ 70 usMask = ( USHORT )( ( 1 << ( USHORT ) ucNBits ) - 1 ); 71 usMask <<= usBitOffset - usByteOffset * BITS_UCHAR; 72 73 /* copy bits into temporary storage. */ 74 usWordBuf = ucByteBuf[usByteOffset]; 75 usWordBuf |= ucByteBuf[usByteOffset + 1] << BITS_UCHAR; 76 77 /* Zero out bit field bits and then or value bits into them. */ 78 usWordBuf = ( USHORT )( ( usWordBuf & ( ~usMask ) ) | usValue ); 79 80 /* move bits back into storage */ 81 ucByteBuf[usByteOffset] = ( UCHAR )( usWordBuf & 0xFF ); 82 ucByteBuf[usByteOffset + 1] = ( UCHAR )( usWordBuf >> BITS_UCHAR ); 83 } 84 85 UCHAR 86 xMBUtilGetBits( UCHAR * ucByteBuf, USHORT usBitOffset, UCHAR ucNBits ) 87 { 88 USHORT usWordBuf; 89 USHORT usMask; 90 USHORT usByteOffset; 91 USHORT usNPreBits; 92 93 /* Calculate byte offset for first byte containing the bit values starting 94 * at usBitOffset. */ 95 usByteOffset = ( USHORT )( ( usBitOffset ) / BITS_UCHAR ); 96 97 /* How many bits precede our bits to set. */ 98 usNPreBits = ( USHORT )( usBitOffset - usByteOffset * BITS_UCHAR ); 99 100 /* Prepare a mask for setting the new bits. */ 101 usMask = ( USHORT )( ( 1 << ( USHORT ) ucNBits ) - 1 ); 102 103 /* copy bits into temporary storage. */ 104 usWordBuf = ucByteBuf[usByteOffset]; 105 usWordBuf |= ucByteBuf[usByteOffset + 1] << BITS_UCHAR; 106 107 /* throw away unneeded bits. */ 108 usWordBuf >>= usNPreBits; 109 110 /* mask away bits above the requested bitfield. */ 111 usWordBuf &= usMask; 112 113 return ( UCHAR ) usWordBuf; 114 } 115 116 eMBException 117 prveMBError2Exception( eMBErrorCode eErrorCode ) 118 { 119 eMBException eStatus; 120 121 switch ( eErrorCode ) 122 { 123 case MB_ENOERR: 124 eStatus = MB_EX_NONE; 125 break; 126 127 case MB_ENOREG: 128 eStatus = MB_EX_ILLEGAL_DATA_ADDRESS; 129 break; 130 131 case MB_ETIMEDOUT: 132 eStatus = MB_EX_SLAVE_BUSY; 133 break; 134 135 default: 136 eStatus = MB_EX_SLAVE_DEVICE_FAILURE; 137 break; 138 } 139 140 return eStatus; 141 } 142