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feat: we be drawing IBM logos in the terminal like it is the 1970s

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Stevan Freeborn
2026-07-16 09:17:21 -05:00
parent ddb240e6d0
commit 6c9a132b37
2 changed files with 130 additions and 38 deletions
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docs/todos.md
+16 -1
View File
@@ -40,4 +40,19 @@
- [x] Parse individual instructions from binary CHIP-8 file
- [x] Print all instructions from CHIP-8 file
- [x] Write all CHIP-8 IBM logo opcodes to CSV file
- [ ] Implement opcodes present in the IMB logo CHIP-8 file
- [x] Implement opcodes present in the IMB logo CHIP-8 file
| x | Opcode | Type | Description |
|---|--------|------|------------------------------|
| x | `00E0` | 00E0 | Clear display |
| x | `1nnn` | 1nnn | Jump to address |
| x | `3xkk` | 3xkk | Skip next if Vx == kk |
| x | `6xkk` | 6xkk | Load register with immediate |
| x | `7xkk` | 7xkk | Add immediate to Vx |
| x | `ANNN` | ANNN | Set index register |
| x | `Bnnn` | Bnnn | Jump to V0 + addr |
| x | `Dxyn` | Dxyn | Draw sprite |
- [ ] Migrate drawing to raylib window
- [ ] Implement remaining instructions
- [ ] Handle keyboard input
main.c
+114 -37
View File
@@ -5,11 +5,14 @@
#include <sys/time.h>
#include <windows.h>
#include <signal.h>
#include <string.h>
#define MEMORY_SIZE 4096
#define PROGRAM_START 512
#define CPU_CLOCK_HZ 600
#define TIMER_HZ 60
#define SCREEN_WIDTH 64
#define SCREEN_HEIGHT 32
const int CYCLES_PER_FRAME = CPU_CLOCK_HZ / TIMER_HZ;
@@ -32,8 +35,11 @@ enum ExitCodes {
typedef struct ChipEight {
uint8_t memory[MEMORY_SIZE];
uint16_t pc;
uint16_t I;
uint8_t V[16];
uint8_t dt;
uint8_t st;
uint32_t display[SCREEN_WIDTH * SCREEN_HEIGHT];
} chip_eight_t;
void println(const char *format, ...) {
@@ -59,6 +65,25 @@ long get_time() {
return ms;
}
void draw(chip_eight_t *chip) {
printf("\033[J\033[H\033[?25l");
for (int i = 0; i < SCREEN_HEIGHT; i++) {
for (int j = 0; j < SCREEN_WIDTH; j++) {
uint32_t screen_pixel = chip->display[i * SCREEN_WIDTH + j];
if (screen_pixel == 1) {
printf("█");
} else {
printf(" ");
}
}
printf("\n");
}
}
int main(int argc, char *argv[]) {
// Sets up Ctrl+C handling
signal(SIGINT, handle_sigint);
@@ -108,21 +133,12 @@ int main(int argc, char *argv[]) {
chip->pc = PROGRAM_START;
chip->dt = 0;
chip->st = 0;
memset(chip->display, 0, sizeof(chip->display));
println("File '%s' loaded successfully", file_path);
fclose(file_ptr);
FILE *csv_file_ptr = fopen("./imb_logo_opcodes.csv", "a");
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) {
@@ -164,14 +180,14 @@ int main(int argc, char *argv[]) {
// oper: >> 8
// oper: &
// mask: 00001111 00000000 (3840)
uint16_t x = (opcode >> 8) & 3840;
uint16_t x = (opcode & 3840) >> 8;
// 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;
uint16_t y = (opcode & 240) >> 4;
// kk or byte - An 8-bit value, the lowest 8 bits of the instruction
// i.e. 00000000 11111111
@@ -179,33 +195,96 @@ int main(int argc, char *argv[]) {
// 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));
// mask: 11110000 00000000
switch(opcode & 61440) {
// Clear display (00E0)
case 0:
if (opcode == 224) {
// println("Clean the display");
memset(chip->display, 0, sizeof(chip->display));
draw(chip);
}
break;
case 4096:
// println("Jump to address: %d", nnn);
chip->pc = nnn;
break;
case 12288:
// println("Skip next");
if (csv_str == NULL) {
println("Failed to allocate memory for csv string");
return -1;
if (chip->V[x] == kk) {
// println("Skipping");
chip->pc += 2;
} else {
// println("Not skipping");
}
break;
case 24576:
// println("Load register with immedate");
chip->V[x] = kk;
break;
case 28672:
// println("Add immedate");
chip->V[x] += kk;
break;
case 40960:
// println("Set index register");
chip->I = nnn;
break;
case 45056:
// println("Jump to V0 + addr");
chip->pc = nnn + chip->V[0];
break;
case 53248:
// println("Draw sprite");
uint8_t x_coordinate = chip->V[x] % SCREEN_WIDTH;
uint8_t y_coordinate = chip->V[y] % SCREEN_HEIGHT;
chip->V[15] = 0;
for (int row = 0; row < n; row++) {
uint8_t sprite_byte = chip->memory[chip->I + row];
if ((y_coordinate + row) >= SCREEN_HEIGHT) {
break;
}
for (int col = 0; col < 8; col++) {
if ((x_coordinate + col) >= SCREEN_WIDTH) {
break;
}
// 0 0 0 0 0 0 0 0
// 1 0 0 0 0 0 0 0
// 0 1 0 0 0 0 0 0
// 0 0 1 0 0 0 0 0
uint8_t sprite_pixel = sprite_byte & (128 >> col);
// ****
// **x*
int sprite_screen_index = ((y_coordinate + row) * SCREEN_WIDTH) + (x_coordinate + col);
uint32_t *screen_pixel = &chip->display[sprite_screen_index];
if (sprite_pixel != 0) {
if (*screen_pixel == 1) {
chip->V[15] = 1;
}
*screen_pixel ^= 1;
}
}
}
draw(chip);
break;
default:
// println("Unhandled opcode: %x", opcode);
break;
}
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--;
}
@@ -226,8 +305,6 @@ int main(int argc, char *argv[]) {
}
}
fclose(csv_file_ptr);
free(chip);
return COMPLETED_SUCCESSFULLY;