diff --git a/main.c b/main.c index 43d4746..651ba7c 100644 --- a/main.c +++ b/main.c @@ -2,9 +2,22 @@ #include #include #include +#include +#include +#include #define MEMORY_SIZE 4096 #define PROGRAM_START 512 +#define CPU_CLOCK_HZ 600 +#define TIMER_HZ 60 + +const int CYCLES_PER_FRAME = CPU_CLOCK_HZ / TIMER_HZ; + +volatile sig_atomic_t keep_running = 1; + +void handle_sigint() { + keep_running = 0; +} enum ExitCodes { COMPLETED_SUCCESSFULLY, @@ -17,7 +30,10 @@ enum ExitCodes { // TODO: Add additional members // i.e. registers typedef struct ChipEight { - uint8_t memory[MEMORY_SIZE] ; + uint8_t memory[MEMORY_SIZE]; + uint16_t pc; + uint8_t dt; + uint8_t st; } chip_eight_t; void println(const char *format, ...) { @@ -32,13 +48,30 @@ void println(const char *format, ...) { printf("\n"); } +long get_time() { + struct timeval tv; + + gettimeofday(&tv, NULL); + + const int ms_per_sec = 1000; + long ms = tv.tv_sec / ms_per_sec; + + return ms; +} + int main(int argc, char *argv[]) { + // Sets up Ctrl+C handling + signal(SIGINT, handle_sigint); + signal(SIGTERM, handle_sigint); + + // Validate file argument if (argc < 2) { println("You fucked up bro! We need a file to load into memory."); println("Usage: chip.exe "); return FILE_NOT_PROVIDED; } + // Load file char* file_path = argv[1]; println("Loading file at %s...", file_path); @@ -56,6 +89,7 @@ int main(int argc, char *argv[]) { if (num_of_bytes > max_program_size) { println("File at '%s' exceeds max program size of %d", file_path, max_program_size); + fclose(file_ptr); return PROGRAM_TOO_LARGE; } @@ -65,22 +99,135 @@ int main(int argc, char *argv[]) { if (chip == NULL) { println("Failed to allocate memory for chip."); + fclose(file_ptr); return MEMORY_ALLOCATION_FAILURE; } fread(&chip->memory[PROGRAM_START], sizeof(uint8_t), num_of_bytes, file_ptr); + + chip->pc = PROGRAM_START; + chip->dt = 0; + chip->st = 0; println("File '%s' loaded successfully", file_path); fclose(file_ptr); - // TODO: Parse instructions - println("INSTRUCTIONS:"); + FILE *csv_file_ptr = fopen("./imb_logo_opcodes.csv", "a"); - for (int i = 0; i < MEMORY_SIZE; i++) { - println("%d: %x ", i, chip->memory[i]); + if (csv_file_ptr == NULL) { + println("Failed to open csv file for writing"); + return -1; } + char *csv_headers = "opcode,nnn,n,x,y,kk\n"; + fprintf(csv_file_ptr, csv_headers); + + // main loop + while(keep_running) { + if (chip->pc > MEMORY_SIZE) { + break; + } + + long frame_start = get_time(); + + for(int i = 0; i < CYCLES_PER_FRAME; i++) { + + // we need to read 2 bytes at at time: + // i.e. 00000000 00000000 + // byte 1: 00011000 + // shift: 00011000 00000000 + // byte 2: 11100110 + // combine: | 11100110 + // + // result: 00011000 11100110 + uint16_t opcode = (chip->memory[chip->pc] << 8) | (chip->memory[chip->pc + 1]); + chip->pc += 2; + + // nnn or addr - A 12-bit value, the lowest 12 bits of the instruction + // i.e. 00001111 11111111 + // value: 11001111 11001100 (53196) + // oper: & + // mask: 0000111111111111 (4095) + // result: 00001111 11001100 (4044) + uint16_t nnn = opcode & 4095; + + // n or nibble - A 4-bit value, the lowest 4 bits of the instruction + // i.e. 00000000 00001111 + // value: 11001111 11001100 (53196) + // oper: & + // mask: 00000000 00001111 (15) + uint16_t n = opcode & 15; + + // x - A 4-bit value, the lower 4 bits of the high byte of the instruction + // i.e. 00001111 00000000 + // oper: >> 8 + // oper: & + // mask: 00001111 00000000 (3840) + uint16_t x = (opcode >> 8) & 3840; + + // y - A 4-bit value, the upper 4 bits of the low byte of the instruction + // i.e. 00000000 11110000 + // oper: >> 4 + // oper: & + // mask: 00000000 11110000 (240) + uint16_t y = (opcode >> 4) & 240; + + // kk or byte - An 8-bit value, the lowest 8 bits of the instruction + // i.e. 00000000 11111111 + // oper: & + // mask: 00000000 11111111 (255) + uint16_t kk = opcode & 255; + + // write headers of variable name to .csv file + // create a string for each opcode that is comma separated + // then write that string into a .csv file + + char *csv_format = "%x,%d,%d,%d,%d,%d\n"; + int len_of_str = snprintf(NULL, 0, csv_format, opcode, nnn, n, x, y, kk); + char *csv_str = malloc((len_of_str + 1) * sizeof(char)); + + if (csv_str == NULL) { + println("Failed to allocate memory for csv string"); + return -1; + } + + snprintf(csv_str, len_of_str + 1, csv_format, opcode, nnn, n, x, y, kk); + fprintf(csv_file_ptr, csv_str); + + free(csv_str); + csv_str = NULL; + + println("opcode: %d", opcode); + println("nnn : %d", nnn); + println("n : %d", n); + println("x : %d", x); + println("y : %d", y); + println("kk : %d", kk); + } + + if (chip->dt > 0) { + chip->dt--; + } + + if (chip->st > 0) { + chip->st++; + // TODO: Play sound + } else { + // TODO: Play sound + } + + float min_diff = 16.66; + long frame_end = get_time(); + long diff = frame_end - frame_start; + + if (diff < min_diff) { + Sleep(min_diff - diff); + } + } + + fclose(csv_file_ptr); + free(chip); return COMPLETED_SUCCESSFULLY;