mirror of https://github.com/sm64pc/sm64pc.git
143 lines
3.2 KiB
C
143 lines
3.2 KiB
C
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
|
|
#include "n64cksum.h"
|
|
#include "utils.h"
|
|
|
|
#define N64CKSUM_VERSION "0.1"
|
|
|
|
// compute N64 ROM checksums
|
|
// buf: buffer with extended SM64 data
|
|
// cksum: two element array to write CRC1 and CRC2 to
|
|
void n64cksum_calc_6102(unsigned char *buf, unsigned int cksum[]) {
|
|
uint32_t t2, t3, t4, t6, t7, t8, s0;
|
|
uint32_t a0, a1, a2, a3;
|
|
uint32_t v0, v1;
|
|
uint32_t seed, end_offset, cur_offset, buf_offset;
|
|
|
|
// derived from the SM64 boot code
|
|
seed = 0xF8CA4DDB; // 0x3f * 0x5d588b65;
|
|
end_offset = 0x100000;
|
|
cur_offset = 0;
|
|
buf_offset = 0x1000;
|
|
seed++;
|
|
a3 = seed;
|
|
t2 = seed;
|
|
t3 = seed;
|
|
s0 = seed;
|
|
a2 = seed;
|
|
t4 = seed;
|
|
|
|
do {
|
|
v0 = read_u32_be(&buf[buf_offset]);
|
|
v1 = a3 + v0;
|
|
a1 = v1;
|
|
if (v1 < a3) {
|
|
t2++;
|
|
}
|
|
v1 = v0 & 0x1F;
|
|
t7 = 32 - v1;
|
|
t8 = v0 >> t7;
|
|
t6 = v0 << v1;
|
|
a0 = t6 | t8;
|
|
a3 = a1;
|
|
t3 ^= v0;
|
|
s0 += a0;
|
|
if (a2 < v0) {
|
|
a2 ^= a3 ^ v0;
|
|
} else {
|
|
a2 ^= a0;
|
|
}
|
|
cur_offset += 4;
|
|
t7 = v0 ^ s0;
|
|
buf_offset += 4;
|
|
t4 += t7;
|
|
} while (cur_offset != end_offset);
|
|
|
|
cksum[0] = (a3 ^ t2) ^ t3;
|
|
cksum[1] = (s0 ^ a2) ^ t4;
|
|
}
|
|
|
|
void n64cksum_update_checksums(uint8_t *buf)
|
|
{
|
|
unsigned int cksum_offsets[] = {0x10, 0x14};
|
|
uint32_t read_cksum[2];
|
|
uint32_t calc_cksum[2];
|
|
int i;
|
|
|
|
// assume CIC-NUS-6102
|
|
INFO("BootChip: CIC-NUS-6102\n");
|
|
|
|
// calculate new N64 header checksum
|
|
n64cksum_calc_6102(buf, calc_cksum);
|
|
|
|
// mimic the n64sums output
|
|
for (i = 0; i < 2; i++) {
|
|
read_cksum[i] = read_u32_be(&buf[cksum_offsets[i]]);
|
|
INFO("CRC%d: 0x%08X ", i+1, read_cksum[i]);
|
|
INFO("Calculated: 0x%08X ", calc_cksum[i]);
|
|
if (calc_cksum[i] == read_cksum[i]) {
|
|
INFO("(Good)\n");
|
|
} else {
|
|
INFO("(Bad)\n");
|
|
}
|
|
}
|
|
|
|
// write checksums into header
|
|
INFO("Writing back calculated Checksum\n");
|
|
write_u32_be(&buf[cksum_offsets[0]], calc_cksum[0]);
|
|
write_u32_be(&buf[cksum_offsets[1]], calc_cksum[1]);
|
|
}
|
|
|
|
#ifdef N64CKSUM_STANDALONE
|
|
static void print_usage(void)
|
|
{
|
|
ERROR("Usage: n64cksum ROM [ROM_OUT]\n"
|
|
"\n"
|
|
"n64cksum v" N64CKSUM_VERSION ": N64 ROM checksum calculator\n"
|
|
"\n"
|
|
"File arguments:\n"
|
|
" ROM input ROM file\n"
|
|
" ROM_OUT output ROM file (default: overwrites input ROM)\n");
|
|
}
|
|
|
|
int main(int argc, char *argv[])
|
|
{
|
|
unsigned char *rom_data;
|
|
char *file_in;
|
|
char *file_out;
|
|
long length;
|
|
long write_length;
|
|
if (argc < 2) {
|
|
print_usage();
|
|
return EXIT_FAILURE;
|
|
}
|
|
|
|
file_in = argv[1];
|
|
if (argc > 2) {
|
|
file_out = argv[2];
|
|
} else {
|
|
file_out = argv[1];
|
|
}
|
|
|
|
length = read_file(file_in, &rom_data);
|
|
if (length < 0) {
|
|
ERROR("Error reading input file \"%s\"\n", file_in);
|
|
return EXIT_FAILURE;
|
|
}
|
|
|
|
n64cksum_update_checksums(rom_data);
|
|
|
|
write_length = write_file(file_out, rom_data, length);
|
|
|
|
free(rom_data);
|
|
|
|
if (write_length != length) {
|
|
ERROR("Error writing to output file \"%s\"\n", file_out);
|
|
return EXIT_FAILURE;
|
|
}
|
|
|
|
return EXIT_SUCCESS;
|
|
}
|
|
#endif // N64CKSUM_STANDALONE
|