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/* 
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 * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
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 * Copyright (c) 2006 Christian Walter <wolti@sil.at>
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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
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. The name of the author may not be used to endorse or promote products
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 *    derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 *
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 * File: $Id: mbutils.c,v 1.6 2007/02/18 23:49:07 wolti Exp $
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 */
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/* ----------------------- System includes ----------------------------------*/
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#include "stdlib.h"
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#include "string.h"
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/* ----------------------- Platform includes --------------------------------*/
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#include "port.h"
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/* ----------------------- Modbus includes ----------------------------------*/
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#include "mb.h"
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#include "mbproto.h"
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/* ----------------------- Defines ------------------------------------------*/
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#define BITS_UCHAR      8U
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/* ----------------------- Start implementation -----------------------------*/
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void
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xMBUtilSetBits( UCHAR * ucByteBuf, USHORT usBitOffset, UCHAR ucNBits,
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                UCHAR ucValue )
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{
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    USHORT          usWordBuf;
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    USHORT          usMask;
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    USHORT          usByteOffset;
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    USHORT          usNPreBits;
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    USHORT          usValue = ucValue;
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    assert( ucNBits <= 8 );
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    assert( ( size_t )BITS_UCHAR == sizeof( UCHAR ) * 8 );
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    /* Calculate byte offset for first byte containing the bit values starting
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     * at usBitOffset. */
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    usByteOffset = ( USHORT )( ( usBitOffset ) / BITS_UCHAR );
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    /* How many bits precede our bits to set. */
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    usNPreBits = ( USHORT )( usBitOffset - usByteOffset * BITS_UCHAR );
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    /* Move bit field into position over bits to set */
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    usValue <<= usNPreBits;
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    /* Prepare a mask for setting the new bits. */
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    usMask = ( USHORT )( ( 1 << ( USHORT ) ucNBits ) - 1 );
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    usMask <<= usBitOffset - usByteOffset * BITS_UCHAR;
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    /* copy bits into temporary storage. */
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    usWordBuf = ucByteBuf[usByteOffset];
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    usWordBuf |= ucByteBuf[usByteOffset + 1] << BITS_UCHAR;
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    /* Zero out bit field bits and then or value bits into them. */
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    usWordBuf = ( USHORT )( ( usWordBuf & ( ~usMask ) ) | usValue );
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    /* move bits back into storage */
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    ucByteBuf[usByteOffset] = ( UCHAR )( usWordBuf & 0xFF );
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    ucByteBuf[usByteOffset + 1] = ( UCHAR )( usWordBuf >> BITS_UCHAR );
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}
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UCHAR
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xMBUtilGetBits( UCHAR * ucByteBuf, USHORT usBitOffset, UCHAR ucNBits )
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{
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    USHORT          usWordBuf;
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    USHORT          usMask;
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    USHORT          usByteOffset;
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    USHORT          usNPreBits;
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    /* Calculate byte offset for first byte containing the bit values starting
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     * at usBitOffset. */
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    usByteOffset = ( USHORT )( ( usBitOffset ) / BITS_UCHAR );
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    /* How many bits precede our bits to set. */
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    usNPreBits = ( USHORT )( usBitOffset - usByteOffset * BITS_UCHAR );
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    /* Prepare a mask for setting the new bits. */
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    usMask = ( USHORT )( ( 1 << ( USHORT ) ucNBits ) - 1 );
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    /* copy bits into temporary storage. */
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    usWordBuf = ucByteBuf[usByteOffset];
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    usWordBuf |= ucByteBuf[usByteOffset + 1] << BITS_UCHAR;
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    /* throw away unneeded bits. */
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    usWordBuf >>= usNPreBits;
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    /* mask away bits above the requested bitfield. */
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    usWordBuf &= usMask;
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    return ( UCHAR ) usWordBuf;
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}
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eMBException
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prveMBError2Exception( eMBErrorCode eErrorCode )
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{
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    eMBException    eStatus;
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    switch ( eErrorCode )
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    {
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        case MB_ENOERR:
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            eStatus = MB_EX_NONE;
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            break;
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        case MB_ENOREG:
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            eStatus = MB_EX_ILLEGAL_DATA_ADDRESS;
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            break;
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        case MB_ETIMEDOUT:
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            eStatus = MB_EX_SLAVE_BUSY;
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            break;
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        default:
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            eStatus = MB_EX_SLAVE_DEVICE_FAILURE;
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            break;
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    }
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    return eStatus;
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}