arch/m68k-amiga/boot/romcheck.c

   1 /*
   2     Copyright © 1995-2010, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: m68k-amiga ROM checksum generator
   6     Lang: english
   7  */
   8
   9 #include <stdint.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <unistd.h>
  13 #include <fcntl.h>
  14 #include <errno.h>
  15
  16 #include <sys/mman.h>
  17
  18 static int amiga_checksum(uint8_t *mem, int size, uint32_t chkoff, int update)
  19 {
  20     uint32_t oldcksum = 0, cksum = 0, prevck = 0;
  21     int i;
  22
  23     for (i = 0; i < size; i+=4) {
  24         uint32_t val = (mem[i+0] << 24) +
  25                        (mem[i+1] << 16) +
  26                        (mem[i+2] <<  8) +
  27                        (mem[i+3] <<  0);
  28
  29         /* Clear old checksum */
  30         if (update && i == chkoff) {
  31                 oldcksum = val;
  32                 val = 0;
  33         }
  34
  35         cksum += val;
  36         if (cksum < prevck)
  37             cksum++;
  38         prevck = cksum;
  39     }
  40
  41     cksum = ~cksum;
  42
  43     if (update && cksum != oldcksum) {
  44         printf("Updating checksum from 0x%08x to 0x%08x\n", oldcksum, cksum);
  45
  46         mem[chkoff + 0] = (cksum >> 24) & 0xff;
  47         mem[chkoff + 1] = (cksum >> 16) & 0xff;
  48         mem[chkoff + 2] = (cksum >>  8) & 0xff;
  49         mem[chkoff + 3] = (cksum >>  0) & 0xff;
  50
  51         return 1;
  52    }
  53
  54    return 0;
  55 }
  56
  57 int main(int argc, char **argv)
  58 {
  59         int err, fd, i;
  60         void *rom;
  61         uint8_t *p;
  62         uint32_t size = 512 * 1024;
  63         off_t len;
  64
  65         fd = open(argv[1], O_RDWR | O_CREAT, 0666);
  66         if (fd < 0) {
  67                 perror(argv[1]);
  68                 return EXIT_FAILURE;
  69         }
  70
  71         /* Pad with 0xff */
  72         for (len = lseek(fd, 0, SEEK_END); len < size; len++) {
  73             unsigned char ff = 0xff;
  74             write(fd, &ff, 1);
  75         }
  76         if (len > size)
  77             printf("Warning: ROM Size > 512KB\n");
  78
  79         rom = mmap(NULL, len, PROT_READ | PROT_WRITE,
  80                         MAP_SHARED, fd, 0);
  81         if (rom == MAP_FAILED) {
  82                 perror(argv[1]);
  83                 close(fd);
  84                 return EXIT_FAILURE;
  85         }
  86
  87         /* add interrupt vector offsets, needed by 68000 and 68010 */
  88         p = (uint8_t*)rom + len - 16;
  89         for (i = 0; i < 7; i++) {
  90                 p[i * 2 + 1] = i + 0x18;
  91                 p[i * 2 + 0] = 0;
  92         }
  93
  94         /* set rom size */
  95         p = (uint8_t*)rom + len - 20;
  96         p[0] = len >> 24;
  97         p[1] = len >> 16;
  98         p[2] = len >>  8;
  99         p[3] = len >>  0;
 100
 101         err = amiga_checksum(rom, len, len - 24, 0);
 102         err = amiga_checksum(rom, len, len - 24, 1);
 103
 104         munmap(rom, len);
 105
 106         close(fd);
 107
 108         return EXIT_SUCCESS;
 109 }
 110
 111