├── roms ├── BRIX ├── MAZE ├── PONG ├── TANK ├── UFO ├── VERS ├── BLINKY ├── BLITZ ├── GUESS ├── HIDDEN ├── KALEID ├── MERLIN ├── MISSILE ├── PONG2 ├── PUZZLE ├── SYZYGY ├── TETRIS ├── TICTAC ├── VBRIX ├── WIPEOFF ├── 15PUZZLE ├── CONNECT4 └── INVADERS ├── doc └── screenshots │ ├── pong.png │ └── invaders.png ├── CMakeLists.txt ├── src ├── chip8.h ├── main.cpp └── chip8.cpp ├── README.md └── LICENSE /roms/BRIX: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/JamesGriffin/CHIP-8-Emulator/HEAD/roms/BRIX -------------------------------------------------------------------------------- /roms/MAZE: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/JamesGriffin/CHIP-8-Emulator/HEAD/roms/MAZE -------------------------------------------------------------------------------- /roms/PONG: -------------------------------------------------------------------------------- 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https://raw.githubusercontent.com/JamesGriffin/CHIP-8-Emulator/HEAD/doc/screenshots/invaders.png -------------------------------------------------------------------------------- /CMakeLists.txt: -------------------------------------------------------------------------------- 1 | cmake_minimum_required(VERSION 2.8.4) 2 | project(CHIP_8_Emulator) 3 | 4 | set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11") 5 | 6 | set(SOURCE_FILES src/main.cpp src/chip8.cpp) 7 | add_executable(chip8 ${SOURCE_FILES}) 8 | 9 | INCLUDE(FindPkgConfig) 10 | 11 | PKG_SEARCH_MODULE(SDL2 REQUIRED sdl2) 12 | 13 | INCLUDE_DIRECTORIES(${SDL2_INCLUDE_DIRS}) 14 | TARGET_LINK_LIBRARIES(chip8 ${SDL2_LIBRARIES}) -------------------------------------------------------------------------------- /src/chip8.h: -------------------------------------------------------------------------------- 1 | #ifndef CHIP_8_H 2 | #define CHIP_8_H 3 | 4 | #include 5 | 6 | class Chip8 { 7 | private: 8 | uint16_t stack[16]; // Stack 9 | uint16_t sp; // Stack pointer 10 | 11 | uint8_t memory[4096]; // Memory (4k) 12 | uint8_t V[16]; // V registers (V0-VF) 13 | 14 | uint16_t pc; // Program counter 15 | uint16_t opcode; // Current op code 16 | uint16_t I; // Index register 17 | 18 | uint8_t delay_timer; // Delay timer 19 | uint8_t sound_timer; // Sound timer 20 | 21 | void init(); 22 | 23 | public: 24 | uint8_t gfx[64 * 32]; // Graphics buffer 25 | uint8_t key[16]; // Keypad 26 | bool drawFlag; // Indicates a draw has occurred 27 | 28 | Chip8(); 29 | ~Chip8(); 30 | 31 | void emulate_cycle(); // Emulate one cycle 32 | bool load(const char *file_path); // Load application 33 | }; 34 | 35 | #endif // CHIP_8_H -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # CHIP-8-Emulator 2 | A CHIP-8 emulator in C++ 3 | 4 | ![Space Invaders](doc/screenshots/invaders.png "Space Invaders") 5 | *Space Invaders* 6 | 7 | ![Pong](doc/screenshots/pong.png "Pong") 8 | *Pong* 9 | 10 | CHIP-8 is an interpretted programming language developed by Joseph Weisbecker in the mid 70s and was initally used on the COSMAC VIP and Telmac 1800 8-bit microcomputers to make game programming easier. CHIP-8 programs are run using a CHIP-8 virtual machine. 11 | 12 | This is a fairly complete implementation of a CHIP-8 virtual machine however there is currently no sound. 13 | 14 | ## Compiling and Running 15 | 16 | Requires cmake and SDL2: 17 | ``` 18 | $ sudo apt-get install cmake libsdl2-dev 19 | ``` 20 | 21 | Compile: 22 | ``` 23 | $ mkdir build 24 | $ cd build 25 | $ cmake .. 26 | $ make 27 | ``` 28 | 29 | Run: 30 | ``` 31 | ./chip8 32 | ``` 33 | 23 (public domain) ROMs are included in the `roms` directory. 34 | 35 | ## References 36 | Some helpful resources I used when writing this 37 | 38 | - http://www.multigesture.net/articles/how-to-write-an-emulator-chip-8-interpreter/ 39 | - http://en.wikipedia.org/wiki/CHIP-8 40 | -------------------------------------------------------------------------------- /src/main.cpp: -------------------------------------------------------------------------------- 1 | #include 2 | #include 3 | #include 4 | #include "stdint.h" 5 | #include "SDL2/SDL.h" 6 | 7 | 8 | #include "chip8.h" 9 | 10 | using namespace std; 11 | 12 | // Keypad keymap 13 | uint8_t keymap[16] = { 14 | SDLK_x, 15 | SDLK_1, 16 | SDLK_2, 17 | SDLK_3, 18 | SDLK_q, 19 | SDLK_w, 20 | SDLK_e, 21 | SDLK_a, 22 | SDLK_s, 23 | SDLK_d, 24 | SDLK_z, 25 | SDLK_c, 26 | SDLK_4, 27 | SDLK_r, 28 | SDLK_f, 29 | SDLK_v, 30 | }; 31 | 32 | int main(int argc, char **argv) { 33 | 34 | // Command usage 35 | if (argc != 2) { 36 | cout << "Usage: chip8 " << endl; 37 | return 1; 38 | } 39 | 40 | Chip8 chip8 = Chip8(); // Initialise Chip8 41 | 42 | int w = 1024; // Window width 43 | int h = 512; // Window height 44 | 45 | // The window we'll be rendering to 46 | SDL_Window* window = NULL; 47 | 48 | // Initialize SDL 49 | if ( SDL_Init(SDL_INIT_EVERYTHING) < 0 ) { 50 | printf( "SDL could not initialize! SDL_Error: %s\n", SDL_GetError() ); 51 | exit(1); 52 | } 53 | // Create window 54 | window = SDL_CreateWindow( 55 | "CHIP-8 Emulator", 56 | SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 57 | w, h, SDL_WINDOW_SHOWN 58 | ); 59 | if (window == NULL){ 60 | printf( "Window could not be created! SDL_Error: %s\n", 61 | SDL_GetError() ); 62 | exit(2); 63 | } 64 | 65 | // Create renderer 66 | SDL_Renderer *renderer = SDL_CreateRenderer(window, -1, 0); 67 | SDL_RenderSetLogicalSize(renderer, w, h); 68 | 69 | // Create texture that stores frame buffer 70 | SDL_Texture* sdlTexture = SDL_CreateTexture(renderer, 71 | SDL_PIXELFORMAT_ARGB8888, 72 | SDL_TEXTUREACCESS_STREAMING, 73 | 64, 32); 74 | 75 | // Temporary pixel buffer 76 | uint32_t pixels[2048]; 77 | 78 | 79 | load: 80 | // Attempt to load ROM 81 | if (!chip8.load(argv[1])) 82 | return 2; 83 | 84 | // Emulation loop 85 | while (true) { 86 | chip8.emulate_cycle(); 87 | 88 | // Process SDL events 89 | SDL_Event e; 90 | while (SDL_PollEvent(&e)) { 91 | if (e.type == SDL_QUIT) exit(0); 92 | 93 | // Process keydown events 94 | if (e.type == SDL_KEYDOWN) { 95 | if (e.key.keysym.sym == SDLK_ESCAPE) 96 | exit(0); 97 | 98 | if (e.key.keysym.sym == SDLK_F1) 99 | goto load; // *gasp*, a goto statement! 100 | // Used to reset/reload ROM 101 | 102 | for (int i = 0; i < 16; ++i) { 103 | if (e.key.keysym.sym == keymap[i]) { 104 | chip8.key[i] = 1; 105 | } 106 | } 107 | } 108 | // Process keyup events 109 | if (e.type == SDL_KEYUP) { 110 | for (int i = 0; i < 16; ++i) { 111 | if (e.key.keysym.sym == keymap[i]) { 112 | chip8.key[i] = 0; 113 | } 114 | } 115 | } 116 | } 117 | 118 | // If draw occurred, redraw SDL screen 119 | if (chip8.drawFlag) { 120 | chip8.drawFlag = false; 121 | 122 | // Store pixels in temporary buffer 123 | for (int i = 0; i < 2048; ++i) { 124 | uint8_t pixel = chip8.gfx[i]; 125 | pixels[i] = (0x00FFFFFF * pixel) | 0xFF000000; 126 | } 127 | // Update SDL texture 128 | SDL_UpdateTexture(sdlTexture, NULL, pixels, 64 * sizeof(Uint32)); 129 | // Clear screen and render 130 | SDL_RenderClear(renderer); 131 | SDL_RenderCopy(renderer, sdlTexture, NULL, NULL); 132 | SDL_RenderPresent(renderer); 133 | } 134 | 135 | // Sleep to slow down emulation speed 136 | std::this_thread::sleep_for(std::chrono::microseconds(1200)); 137 | 138 | } 139 | } -------------------------------------------------------------------------------- /src/chip8.cpp: -------------------------------------------------------------------------------- 1 | #include 2 | #include 3 | #include 4 | #include 5 | #include "time.h" 6 | 7 | 8 | #include "chip8.h" 9 | 10 | unsigned char chip8_fontset[80] = 11 | { 12 | 0xF0, 0x90, 0x90, 0x90, 0xF0, //0 13 | 0x20, 0x60, 0x20, 0x20, 0x70, //1 14 | 0xF0, 0x10, 0xF0, 0x80, 0xF0, //2 15 | 0xF0, 0x10, 0xF0, 0x10, 0xF0, //3 16 | 0x90, 0x90, 0xF0, 0x10, 0x10, //4 17 | 0xF0, 0x80, 0xF0, 0x10, 0xF0, //5 18 | 0xF0, 0x80, 0xF0, 0x90, 0xF0, //6 19 | 0xF0, 0x10, 0x20, 0x40, 0x40, //7 20 | 0xF0, 0x90, 0xF0, 0x90, 0xF0, //8 21 | 0xF0, 0x90, 0xF0, 0x10, 0xF0, //9 22 | 0xF0, 0x90, 0xF0, 0x90, 0x90, //A 23 | 0xE0, 0x90, 0xE0, 0x90, 0xE0, //B 24 | 0xF0, 0x80, 0x80, 0x80, 0xF0, //C 25 | 0xE0, 0x90, 0x90, 0x90, 0xE0, //D 26 | 0xF0, 0x80, 0xF0, 0x80, 0xF0, //E 27 | 0xF0, 0x80, 0xF0, 0x80, 0x80 //F 28 | }; 29 | 30 | Chip8::Chip8() {} 31 | Chip8::~Chip8() {} 32 | 33 | // Initialise 34 | void Chip8::init() { 35 | pc = 0x200; // Set program counter to 0x200 36 | opcode = 0; // Reset op code 37 | I = 0; // Reset I 38 | sp = 0; // Reset stack pointer 39 | 40 | // Clear the display 41 | for (int i = 0; i < 2048; ++i) { 42 | gfx[i] = 0; 43 | } 44 | 45 | // Clear the stack, keypad, and V registers 46 | for (int i = 0; i < 16; ++i) { 47 | stack[i] = 0; 48 | key[i] = 0; 49 | V[i] = 0; 50 | } 51 | 52 | // Clear memory 53 | for (int i = 0; i < 4096; ++i) { 54 | memory[i] = 0; 55 | } 56 | 57 | // Load font set into memory 58 | for (int i = 0; i < 80; ++i) { 59 | memory[i] = chip8_fontset[i]; 60 | } 61 | 62 | // Reset timers 63 | delay_timer = 0; 64 | sound_timer = 0; 65 | 66 | // Seed rng 67 | srand (time(NULL)); 68 | } 69 | 70 | // Initialise and load ROM into memory 71 | bool Chip8::load(const char *file_path) { 72 | // Initialise 73 | init(); 74 | 75 | printf("Loading ROM: %s\n", file_path); 76 | 77 | // Open ROM file 78 | FILE* rom = fopen(file_path, "rb"); 79 | if (rom == NULL) { 80 | std::cerr << "Failed to open ROM" << std::endl; 81 | return false; 82 | } 83 | 84 | // Get file size 85 | fseek(rom, 0, SEEK_END); 86 | long rom_size = ftell(rom); 87 | rewind(rom); 88 | 89 | // Allocate memory to store rom 90 | char* rom_buffer = (char*) malloc(sizeof(char) * rom_size); 91 | if (rom_buffer == NULL) { 92 | std::cerr << "Failed to allocate memory for ROM" << std::endl; 93 | return false; 94 | } 95 | 96 | // Copy ROM into buffer 97 | size_t result = fread(rom_buffer, sizeof(char), (size_t)rom_size, rom); 98 | if (result != rom_size) { 99 | std::cerr << "Failed to read ROM" << std::endl; 100 | return false; 101 | } 102 | 103 | // Copy buffer to memory 104 | if ((4096-512) > rom_size){ 105 | for (int i = 0; i < rom_size; ++i) { 106 | memory[i + 512] = (uint8_t)rom_buffer[i]; // Load into memory starting 107 | // at 0x200 (=512) 108 | } 109 | } 110 | else { 111 | std::cerr << "ROM too large to fit in memory" << std::endl; 112 | return false; 113 | } 114 | 115 | // Clean up 116 | fclose(rom); 117 | free(rom_buffer); 118 | 119 | return true; 120 | } 121 | 122 | // Emulate one cycle 123 | void Chip8::emulate_cycle() { 124 | 125 | // Fetch op code 126 | opcode = memory[pc] << 8 | memory[pc + 1]; // Op code is two bytes 127 | 128 | switch(opcode & 0xF000){ 129 | 130 | // 00E_ 131 | case 0x0000: 132 | 133 | switch (opcode & 0x000F) { 134 | // 00E0 - Clear screen 135 | case 0x0000: 136 | for (int i = 0; i < 2048; ++i) { 137 | gfx[i] = 0; 138 | } 139 | drawFlag = true; 140 | pc+=2; 141 | break; 142 | 143 | // 00EE - Return from subroutine 144 | case 0x000E: 145 | --sp; 146 | pc = stack[sp]; 147 | pc += 2; 148 | break; 149 | 150 | default: 151 | printf("\nUnknown op code: %.4X\n", opcode); 152 | exit(3); 153 | } 154 | break; 155 | 156 | // 1NNN - Jumps to address NNN 157 | case 0x1000: 158 | pc = opcode & 0x0FFF; 159 | break; 160 | 161 | // 2NNN - Calls subroutine at NNN 162 | case 0x2000: 163 | stack[sp] = pc; 164 | ++sp; 165 | pc = opcode & 0x0FFF; 166 | break; 167 | 168 | // 3XNN - Skips the next instruction if VX equals NN. 169 | case 0x3000: 170 | if (V[(opcode & 0x0F00) >> 8] == (opcode & 0x00FF)) 171 | pc += 4; 172 | else 173 | pc += 2; 174 | break; 175 | 176 | // 4XNN - Skips the next instruction if VX does not equal NN. 177 | case 0x4000: 178 | if (V[(opcode & 0x0F00) >> 8] != (opcode & 0x00FF)) 179 | pc += 4; 180 | else 181 | pc += 2; 182 | break; 183 | 184 | // 5XY0 - Skips the next instruction if VX equals VY. 185 | case 0x5000: 186 | if (V[(opcode & 0x0F00) >> 8] == V[(opcode & 0x00F0) >> 4]) 187 | pc += 4; 188 | else 189 | pc += 2; 190 | break; 191 | 192 | // 6XNN - Sets VX to NN. 193 | case 0x6000: 194 | V[(opcode & 0x0F00) >> 8] = opcode & 0x00FF; 195 | pc += 2; 196 | break; 197 | 198 | // 7XNN - Adds NN to VX. 199 | case 0x7000: 200 | V[(opcode & 0x0F00) >> 8] += opcode & 0x00FF; 201 | pc += 2; 202 | break; 203 | 204 | // 8XY_ 205 | case 0x8000: 206 | switch (opcode & 0x000F) { 207 | 208 | // 8XY0 - Sets VX to the value of VY. 209 | case 0x0000: 210 | V[(opcode & 0x0F00) >> 8] = V[(opcode & 0x00F0) >> 4]; 211 | pc += 2; 212 | break; 213 | 214 | // 8XY1 - Sets VX to (VX OR VY). 215 | case 0x0001: 216 | V[(opcode & 0x0F00) >> 8] |= V[(opcode & 0x00F0) >> 4]; 217 | pc += 2; 218 | break; 219 | 220 | // 8XY2 - Sets VX to (VX AND VY). 221 | case 0x0002: 222 | V[(opcode & 0x0F00) >> 8] &= V[(opcode & 0x00F0) >> 4]; 223 | pc += 2; 224 | break; 225 | 226 | // 8XY3 - Sets VX to (VX XOR VY). 227 | case 0x0003: 228 | V[(opcode & 0x0F00) >> 8] ^= V[(opcode & 0x00F0) >> 4]; 229 | pc += 2; 230 | break; 231 | 232 | // 8XY4 - Adds VY to VX. VF is set to 1 when there's a carry, 233 | // and to 0 when there isn't. 234 | case 0x0004: 235 | V[(opcode & 0x0F00) >> 8] += V[(opcode & 0x00F0) >> 4]; 236 | if(V[(opcode & 0x00F0) >> 4] > (0xFF - V[(opcode & 0x0F00) >> 8])) 237 | V[0xF] = 1; //carry 238 | else 239 | V[0xF] = 0; 240 | pc += 2; 241 | break; 242 | 243 | // 8XY5 - VY is subtracted from VX. VF is set to 0 when 244 | // there's a borrow, and 1 when there isn't. 245 | case 0x0005: 246 | if(V[(opcode & 0x00F0) >> 4] > V[(opcode & 0x0F00) >> 8]) 247 | V[0xF] = 0; // there is a borrow 248 | else 249 | V[0xF] = 1; 250 | V[(opcode & 0x0F00) >> 8] -= V[(opcode & 0x00F0) >> 4]; 251 | pc += 2; 252 | break; 253 | 254 | // 0x8XY6 - Shifts VX right by one. VF is set to the value of 255 | // the least significant bit of VX before the shift. 256 | case 0x0006: 257 | V[0xF] = V[(opcode & 0x0F00) >> 8] & 0x1; 258 | V[(opcode & 0x0F00) >> 8] >>= 1; 259 | pc += 2; 260 | break; 261 | 262 | // 0x8XY7: Sets VX to VY minus VX. VF is set to 0 when there's 263 | // a borrow, and 1 when there isn't. 264 | case 0x0007: 265 | if(V[(opcode & 0x0F00) >> 8] > V[(opcode & 0x00F0) >> 4]) // VY-VX 266 | V[0xF] = 0; // there is a borrow 267 | else 268 | V[0xF] = 1; 269 | V[(opcode & 0x0F00) >> 8] = V[(opcode & 0x00F0) >> 4] - V[(opcode & 0x0F00) >> 8]; 270 | pc += 2; 271 | break; 272 | 273 | // 0x8XYE: Shifts VX left by one. VF is set to the value of 274 | // the most significant bit of VX before the shift. 275 | case 0x000E: 276 | V[0xF] = V[(opcode & 0x0F00) >> 8] >> 7; 277 | V[(opcode & 0x0F00) >> 8] <<= 1; 278 | pc += 2; 279 | break; 280 | 281 | default: 282 | printf("\nUnknown op code: %.4X\n", opcode); 283 | exit(3); 284 | } 285 | break; 286 | 287 | // 9XY0 - Skips the next instruction if VX doesn't equal VY. 288 | case 0x9000: 289 | if (V[(opcode & 0x0F00) >> 8] != V[(opcode & 0x00F0) >> 4]) 290 | pc += 4; 291 | else 292 | pc += 2; 293 | break; 294 | 295 | // ANNN - Sets I to the address NNN. 296 | case 0xA000: 297 | I = opcode & 0x0FFF; 298 | pc += 2; 299 | break; 300 | 301 | // BNNN - Jumps to the address NNN plus V0. 302 | case 0xB000: 303 | pc = (opcode & 0x0FFF) + V[0]; 304 | break; 305 | 306 | // CXNN - Sets VX to a random number, masked by NN. 307 | case 0xC000: 308 | V[(opcode & 0x0F00) >> 8] = (rand() % (0xFF + 1)) & (opcode & 0x00FF); 309 | pc += 2; 310 | break; 311 | 312 | // DXYN: Draws a sprite at coordinate (VX, VY) that has a width of 8 313 | // pixels and a height of N pixels. 314 | // Each row of 8 pixels is read as bit-coded starting from memory 315 | // location I; 316 | // I value doesn't change after the execution of this instruction. 317 | // VF is set to 1 if any screen pixels are flipped from set to unset 318 | // when the sprite is drawn, and to 0 if that doesn't happen. 319 | case 0xD000: 320 | { 321 | unsigned short x = V[(opcode & 0x0F00) >> 8]; 322 | unsigned short y = V[(opcode & 0x00F0) >> 4]; 323 | unsigned short height = opcode & 0x000F; 324 | unsigned short pixel; 325 | 326 | V[0xF] = 0; 327 | for (int yline = 0; yline < height; yline++) 328 | { 329 | pixel = memory[I + yline]; 330 | for(int xline = 0; xline < 8; xline++) 331 | { 332 | if((pixel & (0x80 >> xline)) != 0) 333 | { 334 | if(gfx[(x + xline + ((y + yline) * 64))] == 1) 335 | { 336 | V[0xF] = 1; 337 | } 338 | gfx[x + xline + ((y + yline) * 64)] ^= 1; 339 | } 340 | } 341 | } 342 | 343 | drawFlag = true; 344 | pc += 2; 345 | } 346 | break; 347 | 348 | // EX__ 349 | case 0xE000: 350 | 351 | switch (opcode & 0x00FF) { 352 | // EX9E - Skips the next instruction if the key stored 353 | // in VX is pressed. 354 | case 0x009E: 355 | if (key[V[(opcode & 0x0F00) >> 8]] != 0) 356 | pc += 4; 357 | else 358 | pc += 2; 359 | break; 360 | 361 | // EXA1 - Skips the next instruction if the key stored 362 | // in VX isn't pressed. 363 | case 0x00A1: 364 | if (key[V[(opcode & 0x0F00) >> 8]] == 0) 365 | pc += 4; 366 | else 367 | pc += 2; 368 | break; 369 | 370 | default: 371 | printf("\nUnknown op code: %.4X\n", opcode); 372 | exit(3); 373 | } 374 | break; 375 | 376 | // FX__ 377 | case 0xF000: 378 | switch(opcode & 0x00FF) 379 | { 380 | // FX07 - Sets VX to the value of the delay timer 381 | case 0x0007: 382 | V[(opcode & 0x0F00) >> 8] = delay_timer; 383 | pc += 2; 384 | break; 385 | 386 | // FX0A - A key press is awaited, and then stored in VX 387 | case 0x000A: 388 | { 389 | bool key_pressed = false; 390 | 391 | for(int i = 0; i < 16; ++i) 392 | { 393 | if(key[i] != 0) 394 | { 395 | V[(opcode & 0x0F00) >> 8] = i; 396 | key_pressed = true; 397 | } 398 | } 399 | 400 | // If no key is pressed, return and try again. 401 | if(!key_pressed) 402 | return; 403 | 404 | pc += 2; 405 | } 406 | break; 407 | 408 | // FX15 - Sets the delay timer to VX 409 | case 0x0015: 410 | delay_timer = V[(opcode & 0x0F00) >> 8]; 411 | pc += 2; 412 | break; 413 | 414 | // FX18 - Sets the sound timer to VX 415 | case 0x0018: 416 | sound_timer = V[(opcode & 0x0F00) >> 8]; 417 | pc += 2; 418 | break; 419 | 420 | // FX1E - Adds VX to I 421 | case 0x001E: 422 | // VF is set to 1 when range overflow (I+VX>0xFFF), and 0 423 | // when there isn't. 424 | if(I + V[(opcode & 0x0F00) >> 8] > 0xFFF) 425 | V[0xF] = 1; 426 | else 427 | V[0xF] = 0; 428 | I += V[(opcode & 0x0F00) >> 8]; 429 | pc += 2; 430 | break; 431 | 432 | // FX29 - Sets I to the location of the sprite for the 433 | // character in VX. Characters 0-F (in hexadecimal) are 434 | // represented by a 4x5 font 435 | case 0x0029: 436 | I = V[(opcode & 0x0F00) >> 8] * 0x5; 437 | pc += 2; 438 | break; 439 | 440 | // FX33 - Stores the Binary-coded decimal representation of VX 441 | // at the addresses I, I plus 1, and I plus 2 442 | case 0x0033: 443 | memory[I] = V[(opcode & 0x0F00) >> 8] / 100; 444 | memory[I + 1] = (V[(opcode & 0x0F00) >> 8] / 10) % 10; 445 | memory[I + 2] = V[(opcode & 0x0F00) >> 8] % 10; 446 | pc += 2; 447 | break; 448 | 449 | // FX55 - Stores V0 to VX in memory starting at address I 450 | case 0x0055: 451 | for (int i = 0; i <= ((opcode & 0x0F00) >> 8); ++i) 452 | memory[I + i] = V[i]; 453 | 454 | // On the original interpreter, when the 455 | // operation is done, I = I + X + 1. 456 | I += ((opcode & 0x0F00) >> 8) + 1; 457 | pc += 2; 458 | break; 459 | 460 | case 0x0065: 461 | for (int i = 0; i <= ((opcode & 0x0F00) >> 8); ++i) 462 | V[i] = memory[I + i]; 463 | 464 | // On the original interpreter, 465 | // when the operation is done, I = I + X + 1. 466 | I += ((opcode & 0x0F00) >> 8) + 1; 467 | pc += 2; 468 | break; 469 | 470 | default: 471 | printf ("Unknown opcode [0xF000]: 0x%X\n", opcode); 472 | } 473 | break; 474 | 475 | default: 476 | printf("\nUnimplemented op code: %.4X\n", opcode); 477 | exit(3); 478 | } 479 | 480 | 481 | // Update timers 482 | if (delay_timer > 0) 483 | --delay_timer; 484 | 485 | if (sound_timer > 0) 486 | if(sound_timer == 1); 487 | // TODO: Implement sound 488 | --sound_timer; 489 | 490 | } 491 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 2, June 1991 3 | 4 | Copyright (C) 1989, 1991 Free Software Foundation, Inc., 5 | 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 6 | Everyone is permitted to copy and distribute verbatim copies 7 | of this license document, but changing it is not allowed. 8 | 9 | Preamble 10 | 11 | The licenses for most software are designed to take away your 12 | freedom to share and change it. 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You may copy and distribute verbatim copies of the Program's 80 | source code as you receive it, in any medium, provided that you 81 | conspicuously and appropriately publish on each copy an appropriate 82 | copyright notice and disclaimer of warranty; keep intact all the 83 | notices that refer to this License and to the absence of any warranty; 84 | and give any other recipients of the Program a copy of this License 85 | along with the Program. 86 | 87 | You may charge a fee for the physical act of transferring a copy, and 88 | you may at your option offer warranty protection in exchange for a fee. 89 | 90 | 2. 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In such case, this License incorporates 235 | the limitation as if written in the body of this License. 236 | 237 | 9. The Free Software Foundation may publish revised and/or new versions 238 | of the General Public License from time to time. Such new versions will 239 | be similar in spirit to the present version, but may differ in detail to 240 | address new problems or concerns. 241 | 242 | Each version is given a distinguishing version number. If the Program 243 | specifies a version number of this License which applies to it and "any 244 | later version", you have the option of following the terms and conditions 245 | either of that version or of any later version published by the Free 246 | Software Foundation. If the Program does not specify a version number of 247 | this License, you may choose any version ever published by the Free Software 248 | Foundation. 249 | 250 | 10. If you wish to incorporate parts of the Program into other free 251 | programs whose distribution conditions are different, write to the author 252 | to ask for permission. For software which is copyrighted by the Free 253 | Software Foundation, write to the Free Software Foundation; we sometimes 254 | make exceptions for this. Our decision will be guided by the two goals 255 | of preserving the free status of all derivatives of our free software and 256 | of promoting the sharing and reuse of software generally. 257 | 258 | NO WARRANTY 259 | 260 | 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY 261 | FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN 262 | OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES 263 | PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED 264 | OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 265 | MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS 266 | TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE 267 | PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, 268 | REPAIR OR CORRECTION. 269 | 270 | 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING 271 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR 272 | REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, 273 | INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING 274 | OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED 275 | TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY 276 | YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER 277 | PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE 278 | POSSIBILITY OF SUCH DAMAGES. 279 | 280 | END OF TERMS AND CONDITIONS 281 | 282 | How to Apply These Terms to Your New Programs 283 | 284 | If you develop a new program, and you want it to be of the greatest 285 | possible use to the public, the best way to achieve this is to make it 286 | free software which everyone can redistribute and change under these terms. 287 | 288 | To do so, attach the following notices to the program. It is safest 289 | to attach them to the start of each source file to most effectively 290 | convey the exclusion of warranty; and each file should have at least 291 | the "copyright" line and a pointer to where the full notice is found. 292 | 293 | 294 | Copyright (C) 295 | 296 | This program is free software; you can redistribute it and/or modify 297 | it under the terms of the GNU General Public License as published by 298 | the Free Software Foundation; either version 2 of the License, or 299 | (at your option) any later version. 300 | 301 | This program is distributed in the hope that it will be useful, 302 | but WITHOUT ANY WARRANTY; without even the implied warranty of 303 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 304 | GNU General Public License for more details. 305 | 306 | You should have received a copy of the GNU General Public License along 307 | with this program; if not, write to the Free Software Foundation, Inc., 308 | 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. 309 | 310 | Also add information on how to contact you by electronic and paper mail. 311 | 312 | If the program is interactive, make it output a short notice like this 313 | when it starts in an interactive mode: 314 | 315 | Gnomovision version 69, Copyright (C) year name of author 316 | Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 317 | This is free software, and you are welcome to redistribute it 318 | under certain conditions; type `show c' for details. 319 | 320 | The hypothetical commands `show w' and `show c' should show the appropriate 321 | parts of the General Public License. Of course, the commands you use may 322 | be called something other than `show w' and `show c'; they could even be 323 | mouse-clicks or menu items--whatever suits your program. 324 | 325 | You should also get your employer (if you work as a programmer) or your 326 | school, if any, to sign a "copyright disclaimer" for the program, if 327 | necessary. Here is a sample; alter the names: 328 | 329 | Yoyodyne, Inc., hereby disclaims all copyright interest in the program 330 | `Gnomovision' (which makes passes at compilers) written by James Hacker. 331 | 332 | , 1 April 1989 333 | Ty Coon, President of Vice 334 | 335 | This General Public License does not permit incorporating your program into 336 | proprietary programs. If your program is a subroutine library, you may 337 | consider it more useful to permit linking proprietary applications with the 338 | library. If this is what you want to do, use the GNU Lesser General 339 | Public License instead of this License. 340 | --------------------------------------------------------------------------------