1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
|
/***************************************************************************
* https://github.com/dhylands/projects/blob/master/lpc/lpc-vector-checksum/lpc-vector-checksum.c
*
* Copyright (c) 2012 by Dave Hylands
* All Rights Reserved
*
* Permission is granted to any individual or institution to use, copy,
* modify, or redistribute this file so long as it is not sold for profit,
* and that this copyright notice is retained.
*
***************************************************************************
*
* This program calculates the vector checksum used in LPC17xx binary
* images.
*
* Usage: lpc-vector-checksum file
*
***************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <errno.h>
#include <string.h>
/***************************************************************************/
/**
* update_vector_checksum
*
* The algorithim is to write the checksum such that the checksum of the
* first 8 words is equal to zero.
*
* The LPC1768 uses little-endian, and this particular routine assumes
* that it's running on a little-endian architecture.
*/
static int update_vector_checksum( const char *filename )
{
uint32_t sum;
uint32_t header[8];
FILE *fs;
int i;
if (( fs = fopen( filename, "r+b" )) == NULL )
{
fprintf( stderr, "Unable to open '%s' for reading/writing (%d): %s\n",
filename, errno, strerror( errno ));
return 0;
}
if ( fread( header, sizeof( header ), 1, fs ) != 1 )
{
fprintf( stderr, "Failed to read header from '%s' (perhaps the file is too small?)",
filename );
fclose( fs );
return 0;
}
sum = 0;
for ( i = 0; i < 7; i++ )
{
sum += header[i];
}
printf( "sum = 0x%08x, value to write = 0x%08x\n", sum, -sum );
/* write back the checksum to location 7
* http://sigalrm.blogspot.jp/2011/10/cortex-m3-exception-vector-checksum.html
*/
fseek(fs, 0x1c, SEEK_SET);
sum = -sum;
fwrite(&sum, 4, 1, fs);
fclose( fs );
return 1;
}
/***************************************************************************/
/**
* main
*/
int main( int argc, char **argv )
{
int arg;
if ( argc < 2)
{
fprintf( stderr, "Usage: lpc-vector-checksum file ...\n" );
exit( 1 );
}
for ( arg = 1; arg < argc; arg++ )
{
update_vector_checksum( argv[ arg ]);
}
exit( 0 );
return 0;
}
|
