43 lines
757 B
C
43 lines
757 B
C
#include <stdio.h>
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#include <fcntl.h>
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unsigned char rom[ROMSIZE];
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unsigned int sum;
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main(argc,argv)
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int argc; char *argv[];
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{
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int i, fd;
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if (argc < 1) {
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fprintf(stderr,"usage: %s rom-file\n",argv[0]);
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exit(2);
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}
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if ((fd = open(argv[1], O_RDWR)) < 0) {
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perror("unable to open file");
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exit(2);
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}
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bzero(rom, ROMSIZE);
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if (read(fd, rom, ROMSIZE) < 0) {
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perror("read error");
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exit(2);
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}
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rom[5] = 0;
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for (i=0,sum=0; i<ROMSIZE; i++)
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sum += rom[i];
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rom[5] = -sum;
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for (i=0,sum=0; i<ROMSIZE; i++);
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sum += rom[i];
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if (sum)
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printf("checksum fails.\n");
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if (lseek(fd, 0L, SEEK_SET) < 0) {
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perror("unable to seek");
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exit(2);
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}
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if (write(fd, rom, ROMSIZE) < 0) {
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perror("unable to write");
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exit(2);
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}
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close(fd);
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exit(0);
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}
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