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[/] [openrisc/] [trunk/] [bootloaders/] [orpmon/] [gencrc.c] - Blame information for rev 639

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Line No. Rev Author Line
1 2 marcus.erl
/* Generates crc for specified binary file.
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   We do very dirty hack here -- first occurrence of 0xccccccccdddddddd in output file designates where crc
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   and size should be placed. We calculate the crc on the binary and then replace the occurences in the ELF
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   file directly. This was done so, we don't need to */
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#include <stdio.h>
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#define MAX_SIZE 500000
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#ifdef __BIG_ENDIAN__
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#define SWAP32(x) (x)
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#else /* !__BIG_ENDIAN__ */
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#define SWAP32(x) ((((x) >> 24) & 0xff) << 0 \
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                 | (((x) >> 16) & 0xff) << 8 \
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                 | (((x) >> 8) & 0xff) << 16 \
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                 | (((x) >> 0) & 0xff) << 24)
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#endif /* __BIG_ENDIAN__ */
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unsigned char buf[MAX_SIZE];
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unsigned long crc32 (unsigned long crc, const unsigned char *buf, unsigned long len)
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{
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  /* Create bitwise CRC table first */
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  unsigned long crc_table[256];
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  int i, k;
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  for (i = 0; i < 256; i++) {
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    unsigned long c = (unsigned long)i;
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    for (k = 0; k < 8; k++) c = c & 1 ? 0xedb88320 ^ (c >> 1) : c >> 1;
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    crc_table[i] = c;
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  }
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  /* Calculate crc on buf */
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  crc = crc ^ 0xffffffffL;
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  while (len--) crc = crc_table[((int)crc ^ (*buf++)) & 0xff] ^ (crc >> 8);
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  return crc ^ 0xffffffffL;
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}
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int main (int argc, char *argv[])
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{
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  FILE *fi, *fo;
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  int size, i, tsize;
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  unsigned long crc;
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  if (argc != 3) return -1;
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  fi = fopen (argv[1], "rb");
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  fo = fopen (argv[2], "rb+");
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  if (!fi || !fo) return 1;
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  size = fread (buf, 1, MAX_SIZE, fi);
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  fclose (fi);
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  crc = crc32 (0, buf, size);
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  tsize = fread (buf, 1, MAX_SIZE, fo);
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  for (i = 0; i < tsize; i++)
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    if (*((unsigned long *)&buf[i]) == SWAP32(0xcccccccc) && *((unsigned long *)&buf[i + 4]) == SWAP32(0xdddddddd)) {
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      *(unsigned long *)&buf[i] = SWAP32(crc);
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      *(unsigned long *)&buf[i + 4] = SWAP32(size);
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      break;
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    }
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  if (i >= tsize - 8) return 2;
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  fseek (fo, 0l, SEEK_SET);
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  fwrite (buf, 1, tsize, fo);
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  fclose (fo);
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  return 0;
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}

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