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implement simple ops

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This commit is contained in:
Antoni Piasecki
2025-07-11 14:29:47 +02:00
parent cd767c6631
commit 7133d0491a
1 changed files with 194 additions and 34 deletions
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228
chip8.c
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@@ -1,9 +1,22 @@
// http://devernay.free.fr/hacks/chip8/C8TECH10.HTM
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#define READ_INS() \
uint8_t low = c->memory[c->pc++]; \
uint8_t high = c->memory[c->pc++]; \
uint16_t ins = (low << 8) | high; \
uint16_t nnn = ins & 0x0FFF; \
uint8_t n = ins & 0x000F; \
uint8_t x = (ins >> 8) & 0x0F; \
uint8_t y = (ins >> 4) & 0x0F; \
uint8_t kk = ins & 0x00FF
#define BAD_INS() \
fprintf(stderr, "unrecognized instruction\n"); \
exit(1)
typedef struct CHIP8 {
uint8_t *memory;
uint16_t pc;
@@ -42,17 +55,9 @@ CHIP8 chip8_create() {
return c;
}
void chip8_disassemble(CHIP8 *c, size_t size) {
for (size_t i = 0; i < size; i++) {
uint8_t low = c->memory[c->pc++];
uint8_t high = c->memory[c->pc++];
uint16_t ins = (low << 8) | high;
uint16_t nnn = ins & 0x0FFF;
uint8_t n = ins & 0x000F;
uint8_t x = (ins >> 8) & 0x0F;
uint8_t y = (ins >> 4) & 0x0F;
uint8_t kk = ins & 0x00FF;
void chip8_disassemble(CHIP8 *c, size_t ins_count) {
for (size_t i = 0; i < ins_count; i++) {
READ_INS();
switch ((ins >> 12) & 0xF) {
case 0x0: {
@@ -64,29 +69,29 @@ void chip8_disassemble(CHIP8 *c, size_t size) {
puts("RET");
break;
default:
printf("SYS %hd\n", nnn);
printf("SYS %u\n", nnn);
}
} break;
case 0x1: {
printf("JP %hd\n", nnn);
printf("JP %u\n", nnn);
} break;
case 0x2: {
printf("CALL %hd\n", nnn);
printf("CALL %u\n", nnn);
} break;
case 0x3: {
printf("SE V%x, %hhd\n", x, kk);
printf("SE V%x, %u\n", x, kk);
} break;
case 0x4: {
printf("SNE V%x, %hhd\n", x, kk);
printf("SNE V%x, %u\n", x, kk);
} break;
case 0x5: {
printf("SE V%x, V%x\n", x, y);
} break;
case 0x6: {
printf("LD V%x, %hhd\n", x, kk);
printf("LD V%x, %u\n", x, kk);
} break;
case 0x7: {
printf("ADD V%x, %hhd\n", x, kk);
printf("ADD V%x, %u\n", x, kk);
} break;
case 0x8: {
switch (n) {
@@ -118,24 +123,23 @@ void chip8_disassemble(CHIP8 *c, size_t size) {
printf("SHL V%x\n", x);
break;
default:
fprintf(stderr, "unrecognized instruction\n");
exit(1);
BAD_INS();
}
} break;
case 0x9: {
printf("SNE V%x, V%x\n", x, y);
} break;
case 0xA: {
printf("LD I, %hd\n", nnn);
printf("LD I, %u\n", nnn);
} break;
case 0xB: {
printf("JP V0, %hd\n", nnn);
printf("JP V0, %u\n", nnn);
} break;
case 0xC: {
printf("RND V%x, %hd\n", x, kk);
printf("RND V%x, %u\n", x, kk);
} break;
case 0xD: {
printf("DRW V%x, V%x, %hhd\n", x, y, n);
printf("DRW V%x, V%x, %u\n", x, y, n);
} break;
case 0xE: {
switch (kk) {
@@ -146,8 +150,7 @@ void chip8_disassemble(CHIP8 *c, size_t size) {
printf("SKNP V%x\n", x);
break;
default:
fprintf(stderr, "unrecognized instruction\n");
exit(1);
BAD_INS();
}
} break;
case 0xF: {
@@ -180,28 +183,185 @@ void chip8_disassemble(CHIP8 *c, size_t size) {
printf("LD V%x, [I]\n", x);
break;
default:
fprintf(stderr, "unrecognized instruction\n");
exit(1);
BAD_INS();
}
} break;
default:
fprintf(stderr, "unrecognized instruction\n");
exit(1);
BAD_INS();
}
}
}
void chip8_execute(CHIP8 *c) {
while (1) {
READ_INS();
switch ((ins >> 12) & 0xF) {
case 0x0: {
switch (nnn) {
case 0x0E0:
puts("TODO: CLS");
break;
case 0x0EE:
c->pc = c->stack[c->sp];
c->sp--;
break;
default:
c->pc = nnn;
}
} break;
case 0x1: {
c->pc = nnn;
} break;
case 0x2: {
c->sp++;
c->stack[c->sp] = c->pc;
c->pc = nnn;
} break;
case 0x3: {
if (c->reg[x] == kk) {
c->pc += 2;
}
} break;
case 0x4: {
if (c->reg[x] != kk) {
c->pc += 2;
}
} break;
case 0x5: {
if (c->reg[x] == c->reg[y]) {
c->pc += 2;
}
} break;
case 0x6: {
c->reg[x] = kk;
} break;
case 0x7: {
c->reg[x] += kk;
} break;
case 0x8: {
switch (n) {
case 0x0:
c->reg[x] = c->reg[y];
break;
case 0x1:
c->reg[x] |= c->reg[y];
break;
case 0x2:
c->reg[x] &= c->reg[y];
break;
case 0x3:
c->reg[x] ^= c->reg[y];
break;
case 0x4:
printf("TODO: ADD V%x, V%x\n", x, y);
break;
case 0x5:
printf("TODO: SUB V%x, V%x\n", x, y);
break;
case 0x6:
printf("TODO: SHR V%x\n", x);
break;
case 0x7:
printf("TODO: SUBN V%x, V%x\n", x, y);
break;
case 0xE:
printf("TODO: SHL V%x\n", x);
break;
default:
BAD_INS();
}
} break;
case 0x9: {
if (c->reg[x] != c->reg[y]) {
c->pc += 2;
}
} break;
case 0xA: {
c->I = nnn;
} break;
case 0xB: {
c->pc = nnn + c->reg[0];
} break;
case 0xC: {
c->reg[x] = (rand() % 256) & kk;
} break;
case 0xD: {
printf("TODO: DRW V%x, V%x, %u\n", x, y, n);
} break;
case 0xE: {
switch (kk) {
case 0x9E:
printf("TODO: SKP V%x\n", x);
break;
case 0xA1:
printf("TODO: SKNP V%x\n", x);
break;
default:
BAD_INS();
}
} break;
case 0xF: {
switch (kk) {
case 0x07:
c->reg[x] = c->delay_timer;
break;
case 0x0A:
printf("TODO: LD V%x, K\n", x);
break;
case 0x15:
c->delay_timer = c->reg[x];
break;
case 0x18:
c->sound_timer = c->reg[x];
break;
case 0x1E:
c->I += c->reg[x];
break;
case 0x29:
printf("TODO: LD F, V%x\n", x);
break;
case 0x33:
c->memory[c->I] = c->reg[x] / 100;
c->memory[c->I + 1] = (c->reg[x] / 10) % 10;
c->memory[c->I + 2] = c->reg[x] % 10;
break;
case 0x55:
printf("TODO: LD [I], V%x\n", x);
break;
case 0x65:
printf("TODO: LD V%x, [I]\n", x);
break;
default:
BAD_INS();
}
} break;
default:
BAD_INS();
}
}
}
void chip8_free(CHIP8 c) { free(c.memory); }
int main(int argc, char *argv[]) {
if (argc < 2) {
fprintf(stderr, "Usage: %s <path>\n", argv[0]);
return 1;
}
CHIP8 c = chip8_create();
uint8_t buffer[100000];
uint8_t buffer[4000];
FILE *f = fopen(argv[1], "rb");
size_t n = fread(buffer, 1, 100000, f);
size_t n = fread(buffer, 1, 4000, f);
fclose(f);
for (size_t i = 0; i < n; i++) {
c.memory[0x200 + i] = buffer[i];
}
chip8_disassemble(&c, n);
chip8_execute(&c);
chip8_free(c);
}