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-rw-r--r--tool/mbed/lpc-vector-checksum.c99
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diff --git a/tool/mbed/lpc-vector-checksum.c b/tool/mbed/lpc-vector-checksum.c
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+/***************************************************************************
+* 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;
+}
+