1 /*
2 * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
3 * Copyright (c) 2006 Christian Walter <wolti@sil.at>
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
xMBUtilSetBits(UCHAR * ucByteBuf,USHORT usBitOffset,UCHAR ucNBits,UCHAR ucValue)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 assert( ucNBits <= 8 );
57 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
xMBUtilGetBits(UCHAR * ucByteBuf,USHORT usBitOffset,UCHAR ucNBits)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
prveMBError2Exception(eMBErrorCode eErrorCode)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
