diff options
| -rw-r--r-- | CMakeLists.txt | 2 | ||||
| -rw-r--r-- | chip8.c | 132 | ||||
| -rw-r--r-- | main.c | 6 |
3 files changed, 122 insertions, 18 deletions
diff --git a/CMakeLists.txt b/CMakeLists.txt index bda00bc..9f3f950 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -10,7 +10,7 @@ add_executable( chip8 main.c chip8.c chip8.h) -target_compile_options(chip8 PRIVATE -Wall) +target_compile_options(chip8 PRIVATE -Wall -Wextra) target_link_libraries(chip8 PRIVATE SDL2::SDL2) @@ -96,10 +96,8 @@ chip8_draw_sprite(int startx, int starty, uint16_t mem, uint8_t size) /* * draw sprite located at loc of height size at startx,starty */ - uint8_t byte = 0; uint8_t mask = 0x1; - V[0xF] = 0; /* set collision register to 0 */ for (uint8_t byteoffset = 0; byteoffset < size; byteoffset++) { /* loop through each byte from mem to mem+size */ @@ -110,12 +108,10 @@ chip8_draw_sprite(int startx, int starty, uint16_t mem, uint8_t size) if (byte & mask) { uint32_t pixel = WIDTH*(starty%HEIGHT)+((startx%WIDTH)+bit); - if (video[pixel] != 0) - { - /* if the video bit is already set, we need to set the collision register */ - V[0xF] = 1; - } + /* if the video bit is already set, we need to set the collision register */ + V[0xF] = (video[pixel] != 0) ? 1 : 0; video[pixel] ^= PIXEL_COLOR; + draw_flag = 1; } bit++; } @@ -155,7 +151,7 @@ chip8_cycle() uint8_t x = (opcode >> 8) & 0x000F; // lower 4 bits of the high byte, we discard the low byte by right shifting it out uint8_t y = (opcode >> 4) & 0x000F; // upper 4 bits of the low byte, so we need to discard the lower 4 bits uint8_t kk = opcode & 0x00FF; // lowest 8 bits - printf("parsing at 0x%03X\n", PC); + printf("parsing at 0x%03X opcode = 0x%04X\n", PC, opcode); PC += 2; // TODO: remove switch (opcode & 0xF000) { @@ -189,18 +185,15 @@ chip8_cycle() break; case 0x3000: /* SE Vx, byte (skip next instruction if Vx = kk) */ // TODO: not tested - if (V[x] == kk) - PC += 2; + PC += (V[x] == kk) ? 2 : 0; break; case 0x4000: /* SN Vx, byte (skip next instruction if Vx != kk) */ // TODO: not tested - if (V[x] != kk) - PC += 2; + PC += (V[x] != kk) ? 2 : 0; break; case 0x5000: /* SE Vx, Vy (skip next instruction if Vx == Vy) */ // TODO: not tested - if (V[x] == V[y]) - PC += 2; + PC += (V[x] == V[y]) ? 2 : 0; break; case 0x6000: /* LD Vx, byte (load byte in register x) */ { @@ -264,6 +257,117 @@ chip8_cycle() break; default: unknown_opcode(opcode); } + break; + } + case 0x9000: /* SNE Vx, Vy (skip next instruction if Vx != Vy) */ + // TODO: not tested + PC += (V[x] != V[y]) ? 2 : 0; + break; + case 0xA000: /* LD I, addr (load register I with addr) */ + // TODO: not tested + I = nnn; + break; + case 0xB000: /* JP V0, addr (set PC to location nnn + V0) */ + // TODO: not tested + PC = V[0] + nnn; + break; + case 0xC000: /* RND Vx, byte (set Vx to a random byte and AND it by kk) */ + // TODO: not tested + V[x] = (rand() % 256) & kk; // random number between 0 and 255 + break; + case 0xD000: /* DRW Vx, Vy, n (read n bytes from starting starting at address in register I, and draws then at coordinates x,y */ + // TODO: not tested + chip8_draw_sprite(V[x], V[y], I, n); + break; + case 0xE000: /* key input */ + { + switch(kk) + { + case 0x9E: /* SKP Vx (skip next instruction if key Vx is pressed) */ + // TODO: not tested + PC += (key[V[x]] == 1) ? 2 : 0; + break; + case 0xA1: /* SKNP Vx (skip next instruction if key Vx is not pressed) */ + // TODO: not tested + PC += (key[V[x]] == 0) ? 2 : 0; + break; + default: unknown_opcode(opcode); + } + break; + } + case 0xF000: + { + switch (kk) + { + case 0x07: /* LD Vx, DT (load Vx with the value of delay timer register) */ + // TODO: not tested + V[x] = delay_timer; + break; + case 0x0A: /* LD Vx, K (all execution stops until a key is pressed, then that key is put into Vx) */ + { + // TODO: not tested + int found_key = 0; + for (int i = 0; i < 15; i++) + { + V[x] = key[i]; + if (V[x] == 1) + found_key = 1; + } + PC -= (found_key == 0) ? 2 : 0; + break; + } + case 0x15: /* LD DT, Vx (delay timer is set to the value of Vx */ + // TODO: not tested + delay_timer = V[x]; + break; + case 0x18: /* LD ST, Vx (sound timer is set to the value of Vx */ + // TODO: not tested + sound_timer = V[x]; + break; + case 0x1E: /* ADD I, Vx (set I register to I + Vx) */ + // TODO: not tested + I += V[x]; + break; + case 0x29: /* LD F, Vx (set register I to location of the hex sprite Vx) */ + // TODO: not tested + I = V[x] * 5; + break; + case 0x33: /* LD B, Vx (store BCD representation of Vx in memory locations I, I+1 and I+2) */ + // TODO: not tested + memory[I] = (V[x] % 1000) / 100; + memory[I+1] = (V[x] % 100) / 10; + memory[I+2] = (V[x] % 10); + break; + case 0x55: /* LD [I], Vx (store registers V0 through Vx starting at memory location I) */ + { + // TODO: not tested + int reg = 0; + do + { + memory[I+reg] = V[reg]; + reg++; + } + while (reg <= V[x]); + break; + } + case 0x65: /* LD Vx, [I] (read registers V0 through Vx from memory starting at I) */ + { + // TODO: not tested + int reg = 0; + int target = V[x]; + do + { + V[reg] = memory[I+reg]; + reg++; + } + while (reg < target); + break; + } + break; + + default: unknown_opcode(opcode); + } + break; } default: unknown_opcode(opcode); } @@ -14,7 +14,7 @@ */ #define VIDEO_SCALE 5 -#define STEPPING 1 // set to 1 to step manually through program +#define STEPPING 0 // set to 1 to step manually through program SDL_Window *window; SDL_Renderer *renderer; @@ -205,13 +205,14 @@ int main(int argc, char *argv[]) init_video(); - const int fps = 1; + const int fps = 500; const int frame_delay = 1000/fps; uint32_t frame_start; uint32_t frame_time; int do_quit = 0; + /* chip8_draw_sprite(0, 0, 0xD*5, 0x5); chip8_draw_sprite(5, 0, 0xE*5, 0x5); chip8_draw_sprite(10, 0, 0xA*5, 0x5); @@ -230,7 +231,6 @@ int main(int argc, char *argv[]) chip8_draw_sprite(30, 9, 0xE*5, 0x5); chip8_draw_sprite(35, 9, 0xf*5, 0x5); - /* chip8_draw_sprite(0, 20, 0x200, 0x6); chip8_draw_sprite(8, 20, 0x200, 0x6); chip8_draw_sprite(16, 20, 0x200, 0x6); |