ref: 2b2c1ac64906ba61ab713d2e2462a2ca9fb8d05c
dir: /tools/stadium.c/
#include <stdio.h> #include <stdlib.h> #include <stdbool.h> #include <getopt.h> #include <string.h> #include <stdint.h> #include "common.h" // The Game Boy cartridge header stores a global checksum at 0x014E-0x014F #define GLOBALOFF 0x014E // "base" data; Crystal-only #define BASESIZE 24 // ASCII "N64PS3" header #define N64PS3SIZE 6 // N64PS3 + CRC #define HEADERSIZE (N64PS3SIZE + 2) // Checksum every half-bank #define CHECKSIZE 0x2000 // The CRC initial value (also used for checksums) #define CRC_INIT 0xFEFE // The CRC polynomial value #define CRC_POLY 0xC387 typedef enum Base { BASE_NONE, BASE_US, BASE_EU, BASE_DEBUG } Base; uint8_t us_base[BASESIZE] = {'b', 'a', 's', 'e', 0x01, 0x00, 0xBF, 0x6B, 0x40, 0x11, 0x00, 0x22, 0x00, 0x3A, 0xF3, 0x38, 0x18, 0xFF, 0xFF, 0x0F, 0x07, 0x10, 0x68, 0x07}; uint8_t eu_base[BASESIZE] = {'b', 'a', 's', 'e', 0x01, 0x01, 0x1E, 0xCF, 0x00, 0x10, 0x00, 0x00, 0x00, 0x0C, 0xA3, 0x38, 0x00, 0xFF, 0xFF, 0x07, 0x00, 0x00, 0x00, 0x14}; uint8_t dbg_base[BASESIZE] = {'b', 'a', 's', 'e', 0x01, 0x00, 0x07, 0x82, 0x40, 0x10, 0x00, 0x22, 0x00, 0x3A, 0xE3, 0x38, 0x00, 0xFF, 0xFF, 0x07, 0x07, 0x10, 0x68, 0x06}; uint8_t n64ps3[N64PS3SIZE] = {'N', '6', '4', 'P', 'S', '3'}; static void usage(void) { fprintf(stderr, "Usage: stadium [-h|--help] [-b|--base us|eu|dbg] romfile\n"); } void parse_args(int argc, char *argv[], Base *b) { struct option long_options[] = { {"base", required_argument, 0, 'b'}, {"help", no_argument, 0, 'h'}, {0} }; for (int opt = 0; opt != -1;) { switch (opt = getopt_long(argc, argv, "hb:", long_options)) { case 'h': usage(); exit(0); break; case 'b': *b = !strcmp(optarg, "us") ? BASE_US : !strcmp(optarg, "eu") ? BASE_EU : !strcmp(optarg, "dbg") ? BASE_DEBUG : BASE_NONE; break; case 0: case -1: break; default: usage(); exit(1); break; } } } #define SET_U16BE(file, off, v) do { \ file[(off) + 0] = (uint8_t)(((v) & 0xFF00) >> 8); \ file[(off) + 1] = (uint8_t)(((v) & 0x00FF) >> 0); \ } while (0) void calculate_checksums(uint8_t *file, int filesize, Base base) { int NUMCHECKS = filesize / CHECKSIZE; int DATASIZE = HEADERSIZE + NUMCHECKS * 2; // 2 bytes per checksum int ORIGIN = filesize - DATASIZE; // Stadium data goes at the end of the file // Clear the global checksum SET_U16BE(file, GLOBALOFF, 0); // Write the appropriate base data, or none int BASEOFF = ORIGIN - BASESIZE; if (base == BASE_US) { memcpy(file + BASEOFF, us_base, BASESIZE); } else if (base == BASE_EU) { memcpy(file + BASEOFF, eu_base, BASESIZE); } else if (base == BASE_DEBUG) { memcpy(file + BASEOFF, dbg_base, BASESIZE); } // Initialize the Stadium data (this should be free space anyway) memset(file + ORIGIN, 0, DATASIZE); memcpy(file + ORIGIN, n64ps3, N64PS3SIZE); // Calculate the half-bank checksums for (int i = 0; i < NUMCHECKS; i++) { uint16_t checksum = CRC_INIT; for (int j = 0; j < CHECKSIZE; j++) { checksum += file[i * CHECKSIZE + j]; } SET_U16BE(file, ORIGIN + HEADERSIZE + i * 2, checksum); } // Initialize the CRC table uint16_t crc_table[256]; for (int i = 0; i < 256; i++) { uint16_t c = i; uint16_t rem = 0; for (int y = 0; y < 8; y++) { rem = (rem >> 1) ^ ((rem ^ c) & 1 ? CRC_POLY : 0); c >>= 1; } crc_table[i] = rem; } // Calculate the CRC of the half-bank checksums uint16_t crc = CRC_INIT; for (int i = ORIGIN + HEADERSIZE; i < ORIGIN + DATASIZE; i++) { crc = (crc >> 8) ^ crc_table[(crc & 0xFF) ^ file[i]]; } SET_U16BE(file, ORIGIN + HEADERSIZE - 2, crc); // Calculate the global checksum uint16_t globalsum = 0; for (int i = 0; i < filesize; i++) { globalsum += file[i]; } SET_U16BE(file, GLOBALOFF, globalsum); } int main(int argc, char *argv[]) { Base base = BASE_NONE; parse_args(argc, argv, &base); argc -= optind; argv += optind; if (argc < 1) { usage(); exit(1); } char *filename = argv[0]; int filesize; uint8_t *file = read_u8(filename, &filesize); calculate_checksums(file, filesize, base); write_u8(filename, file, filesize); return 0; }