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cc65/util/gamate/gamate-fixcart.c
polluks2 d0e9ceb2b5
Some clean-up
One exit() too much
file is not optional
2022-04-03 00:06:45 +02:00

36 lines
701 B
C

#include <stdlib.h>
#include <stdio.h>
FILE *in;
unsigned int n, i, c;
void usage(char *arg)
{
printf("usage: %s file\n", arg);
}
int main(int argc, char *argv[]) {
if (argc < 2) {
usage(argv[0]);
exit(-1);
}
if (!(in = fopen(argv[1], "r+b"))) {
fprintf(stderr, "couldnt open: '%s'\n", argv[1]);
exit(-1);
}
/* read 0x1000 bytes from 0x7000-0x7fff (offset 0x1000) */
fseek(in, 0x1000, SEEK_SET);
n = 0; for (i = 0; i < 0x1000; i++) {
c = fgetc(in);
n += c;
}
/* write checksum to header */
fseek(in, 0, SEEK_SET);
fputc(n & 0xff, in);
fputc((n >> 8) & 0xff, in);
fclose(in);
return 0;
}