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Merge pull request #2 from KaleviKolttonen/input_file_offset 

Add a command line option -s for specifying file offset to start disa…
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Tennessee Carmel-Veilleux 2018-02-21 09:40:34 -05:00 committed by GitHub
parent 91f4853529 ab33fe1c84
commit 2c46640706
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1 changed files with 23 additions and 0 deletions
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dcc6502.c
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@ -75,6 +75,7 @@ typedef struct options_s {
int hex_output; /* 1 if hex dump output is desired at beginning of line */
unsigned long max_num_bytes;
uint16_t org; /* Origin of addresses */
long offset; /* File offset to start disassembly from */
} options_t;
/* Opcode table */
@ -613,6 +614,7 @@ static void usage(void) {
fprintf(stderr, " -?/-h : Show this help message\n");
fprintf(stderr, " -o ORIGIN : Set the origin (base address of disassembly) [default: 0x8000]\n");
fprintf(stderr, " -m NUM_BYTES : Only disassemble the first NUM_BYTES bytes\n");
fprintf(stderr, " -s NUM_BYTES : Disassemble after skipping NUM_BYTES from start of input file\n");
fprintf(stderr, " -d : Enable hex dump within disassembly\n");
fprintf(stderr, " -n : Enable NES register annotations\n");
fprintf(stderr, " -v : Get only version information\n");
@ -653,6 +655,7 @@ static void parse_args(int argc, char *argv[], options_t *options) {
options->nes_mode = 0;
options->org = 0x8000;
options->max_num_bytes = 65536;
options->offset = 0;
while (arg_idx < argc) {
/* First non-dash-starting argument is assumed to be filename */
@ -703,6 +706,17 @@ static void parse_args(int argc, char *argv[], options_t *options) {
}
options->max_num_bytes = tmp_value;
break;
case 's':
if ((arg_idx == (argc - 1)) || (argv[arg_idx + 1][0] == '-')) {
usage_and_exit(1, "Missing argument to -s switch");
}
/* Get argument and parse it */
arg_idx++;
if (!str_arg_to_ulong(argv[arg_idx], &tmp_value)) {
usage_and_exit(1, "Invalid argument to -s switch");
}
options->offset = (long)tmp_value;
break;
default:
version();
usage();
@ -727,6 +741,7 @@ int main(int argc, char *argv[]) {
FILE *input_file; /* Input file */
uint16_t pc; /* Program counter */
options_t options; /* Command-line options parsing results */
int result = 0;
parse_args(argc, argv, &options);
@ -744,6 +759,14 @@ int main(int argc, char *argv[]) {
exit(2);
}
if (options.offset) {
result = fseek(input_file, options.offset, SEEK_SET);
if (result < 0) {
fprintf(stderr, "fseek(%s, %ld, SEEK_SET) failed: %s (%d)\n", options.filename, options.offset, strerror(errno), result);
exit(2);
}
}
byte_count = 0;
while(!feof(input_file) && ((options.org + byte_count) <= 0xFFFFu) && (byte_count < options.max_num_bytes)) {
fread(&buffer[options.org + byte_count], 1, 1, input_file);