commit b089101d50de1271b2f567ef6536b1fe2f70382a
parent f7fb7be8726576bcc5c1687d9d3e41ca25021f8c
Author: Christos Margiolis <christos@margiolis.net>
Date: Thu, 3 Sep 2020 03:10:32 +0300
added everything in one file
Diffstat:
| M | .gitignore | | | 3 | +-- |
| M | Makefile | | | 30 | +++++++++++------------------- |
| A | chip8.c | | | 420 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
| D | src/chip8.c | | | 306 | ------------------------------------------------------------------------------- |
| D | src/chip8.h | | | 34 | ---------------------------------- |
| D | src/main.c | | | 88 | ------------------------------------------------------------------------------- |
6 files changed, 432 insertions(+), 449 deletions(-)
diff --git a/.gitignore b/.gitignore
@@ -1,3 +1,2 @@
/roms/*
-/obj/
-/bin/
+*.o
diff --git a/Makefile b/Makefile
@@ -1,17 +1,8 @@
TARGET = chip8
INSTALL_PATH = /usr/local/bin
-SRC_DIR = src
-OBJ_DIR = obj
-BIN_DIR = bin
-
-SRC = $(wildcard $(SRC_DIR)/*.c)
-OBJ = $(SRC:$(SRC_DIR)/%.c=$(OBJ_DIR)/%.o)
-
-CP=cp
-MOVE = mv
-MKDIR_P = mkdir -p
-RM_DIR=rm -rf
+SRC = $(wildcard *.c)
+OBJ = $(SRC:%.c=%.o)
CC = gcc
CPPFLAGS += -Iinclude -pedantic
@@ -19,24 +10,25 @@ CFLAGS += -Wall -std=c99 -O3
LDFLAGS += -Llib
LDLIBS += -lSDL2
+CP=cp
+MOVE = mv
+MKDIR_P = mkdir -p
+
.PHONY: all clean
all: $(TARGET)
$(TARGET): $(OBJ)
- $(MKDIR_P) $(BIN_DIR)
$(CC) $(LDFLAGS) $^ $(LDLIBS) -o $@
- $(MOVE) $(TARGET) $(BIN_DIR)
-$(OBJ_DIR)/%.o: $(SRC_DIR)/%.c
- $(MKDIR_P) $(OBJ_DIR)
+%.o: %.c
$(CC) $(CPPFLAGS) $(CFLAGS) -c $< -o $@
run:
- ./$(BIN_DIR)/$(TARGET)
+ ./$(TARGET)
install: $(TARGET)
- $(CP) $(BIN_DIR)/$(TARGET) $(INSTALL_PATH)
-
+ $(CP) $(TARGET) $(INSTALL_PATH)
+
clean:
- $(RM_DIR) $(OBJ_DIR) $(BIN_DIR)
+ $(RM) $(OBJ) $(TARGET)
diff --git a/chip8.c b/chip8.c
@@ -0,0 +1,420 @@
+#define _DEFAULT_SOURCE
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <SDL2/SDL.h>
+
+#define TRUE 1
+#define FALSE 0
+
+struct Chip8 {
+ uint8_t memory[4096];
+ uint8_t V[16];
+ uint8_t gfx[64 * 32];
+ uint8_t keys[16];
+ uint8_t delaytimer;
+ uint8_t soundtimer;
+ uint8_t drawflag;
+ uint16_t stack[16];
+ uint16_t sp;
+ uint16_t opcode;
+ uint16_t I;
+ uint16_t pc;
+};
+
+static const uint8_t keymap[16] = {
+ SDLK_1, SDLK_2, SDLK_3, SDLK_4,
+ SDLK_q, SDLK_w, SDLK_e, SDLK_r,
+ SDLK_a, SDLK_s, SDLK_d, SDLK_f,
+ SDLK_z, SDLK_x, SDLK_c, SDLK_v
+};
+
+static void chip8_init(struct Chip8 *);
+static int romload(struct Chip8 *, const char *);
+static void emulate(struct Chip8 *);
+static int decode(struct Chip8 *);
+static void timers_update(struct Chip8 *);
+static int evts(struct Chip8 *);
+static void render(SDL_Renderer *, SDL_Texture *, struct Chip8 *);
+
+#define V chip8->V
+#define pc chip8->pc
+#define opcode chip8->opcode
+#define I chip8->I
+#define sp chip8->sp
+#define memory chip8->memory
+#define gfx chip8->gfx
+#define stack chip8->stack
+#define keys chip8->keys
+#define delaytimer chip8->delaytimer
+#define soundtimer chip8->soundtimer
+#define drawflag chip8->drawflag
+
+void
+chip8_init(struct Chip8 *chip8)
+{
+ uint8_t fontset[80] = {
+ 0xF0, 0x90, 0x90, 0x90, 0xF0, // 0
+ 0x20, 0x60, 0x20, 0x20, 0x70, // 1
+ 0xF0, 0x10, 0xF0, 0x80, 0xF0, // 2
+ 0xF0, 0x10, 0xF0, 0x10, 0xF0, // 3
+ 0x90, 0x90, 0xF0, 0x10, 0x10, // 4
+ 0xF0, 0x80, 0xF0, 0x10, 0xF0, // 5
+ 0xF0, 0x80, 0xF0, 0x90, 0xF0, // 6
+ 0xF0, 0x10, 0x20, 0x40, 0x40, // 7
+ 0xF0, 0x90, 0xF0, 0x90, 0xF0, // 8
+ 0xF0, 0x90, 0xF0, 0x10, 0xF0, // 9
+ 0xF0, 0x90, 0xF0, 0x90, 0x90, // A
+ 0xE0, 0x90, 0xE0, 0x90, 0xE0, // B
+ 0xF0, 0x80, 0x80, 0x80, 0xF0, // C
+ 0xE0, 0x90, 0x90, 0x90, 0xE0, // D
+ 0xF0, 0x80, 0xF0, 0x80, 0xF0, // E
+ 0xF0, 0x80, 0xF0, 0x80, 0x80 // F
+ };
+ pc = 0x200;
+ opcode = 0;
+ I = 0;
+ sp = 0;
+ delaytimer = 0;
+ soundtimer = 0;
+ memset(V, 0, 16 * sizeof(uint8_t));
+ memset(keys, 0, 16 * sizeof(uint8_t));
+ memset(stack, 0, 16 * sizeof(uint16_t));
+ memset(gfx, 0, 2048 * sizeof(uint8_t));
+ memset(memory, 0, 4096 * sizeof(uint8_t));
+ int i;
+ for (i = 0; i < 80; memory[i] = fontset[i], i++);
+}
+
+int
+romload(struct Chip8 *chip8, const char *fpath)
+{
+ FILE *rom = fopen(fpath, "rb");
+ if (rom == NULL) {
+ fprintf(stderr, "Error loading ROM (%s). Exiting. . .\n", fpath);
+ return FALSE;
+ }
+ fseek(rom, 0, SEEK_END);
+ long romsize = ftell(rom);
+ rewind(rom);
+
+ char *buf = (char *)malloc(romsize * sizeof(char));
+ if (buf == NULL) {
+ fprintf(stderr, "Cannot allocate memory. Exiting. . .\n");
+ return FALSE;
+ }
+
+ size_t res = fread(buf, sizeof(char), (size_t)romsize, rom);
+ if (res != romsize) {
+ fprintf(stderr, "Error reading ROM. Exiting. . .\n");
+ return FALSE;
+ }
+
+ int i;
+ if ((4096 - 512) > romsize)
+ for (i = 0; i < romsize; i++)
+ memory[i + 512] = (uint8_t)buf[i];
+ else {
+ fprintf(stderr, "ROM can't fit into memory. Exiting. . .\n");
+ return FALSE;
+ }
+
+ fclose(rom);
+ free(buf);
+ return TRUE;
+}
+
+void
+emulate(struct Chip8 *chip8)
+{
+ opcode = memory[pc] << 8 | memory[pc + 1]; // fetch
+ if (decode(chip8)) {
+ pc += 2; // execute
+ timers_update(chip8);
+ }
+ printf("Opcode: %x\tMemory: %x\tI: %x\tSP: %x\tPC: %d\n",
+ opcode, memory[pc] << 8 | memory[pc + 1], I, sp, pc);
+}
+
+int
+decode(struct Chip8 *chip8)
+{
+ switch (opcode & 0xF000) {
+ int i;
+ case 0x0000: // 00E_
+ switch (opcode & 0x00FF) {
+ case 0xE0: // 00E0 - Clear screen
+ memset(gfx, 0, 2048 * sizeof(uint8_t));
+ drawflag = TRUE;
+ break;
+ case 0xEE: // 00EE - Return from subroutine
+ pc = stack[--sp];
+ break;
+ default:
+ fprintf(stderr, "Unknown opcode: %x\n", opcode);
+ return FALSE;
+ }
+ break;
+ case 0x1000: // 1NNN - Jump to address NNN
+ pc = (opcode & 0x0FFF) - 2;
+ break;
+ case 0x2000: // 2NNN - Call subroutine at NNN
+ stack[sp++] = pc;
+ pc = (opcode & 0x0FFF) - 2;
+ case 0x3000: // 3NNN - Skip next instruction if VX == NN
+ if (V[(opcode & 0x0F00) >> 8] == (opcode & 0x00FF)) pc += 2;
+ break;
+ case 0x4000: // 4NNN - Skip next instruction if VX != NN
+ if (V[(opcode & 0x0F00) >> 8] != (opcode & 0x00FF)) pc += 2;
+ break;
+ case 0x5000: // 5XY0 - Skip next instruction if VX == VY
+ if (V[(opcode & 0x0F00) >> 8] == V[(opcode & 0x00F0) >> 4]) pc += 2;
+ break;
+ case 0x6000: // 6XNN - Set VX to NN
+ V[(opcode & 0x0F00) >> 8] = opcode & 0x00FF;
+ break;
+ case 0x7000: // 7XNN - Add NN to VX
+ V[(opcode & 0x0F00) >> 8] += opcode & 0x00FF;
+ break;
+ case 0x8000: // 8XY_
+ switch (opcode & 0x000F) {
+ case 0x0000: // 8XY0 - Set VX to VY
+ V[(opcode & 0x0F00) >> 8] = V[(opcode & 0x00F0) >> 4];
+ break;
+ case 0x0001: // 8XY1 - Set VX to (VX OR VY)
+ V[(opcode & 0x0F00) >> 8] |= V[(opcode & 0x00F0) >> 4];
+ break;
+ case 0x0002: // 8XY2 - Set VX to (VX AND VY)
+ V[(opcode & 0x0F00) >> 8] &= V[(opcode & 0x00F0) >> 4];
+ break;
+ case 0x0003: // 8XY3 - Set VX to (VX XOR VY)
+ V[(opcode & 0x0F00) >> 8] ^= V[(opcode & 0x00F0) >> 4];
+ break;
+ case 0x0004: // 8XY4 - Add VY to VX, VF = 1 if there is a carry
+ V[(opcode & 0x0F00) >> 8] += V[(opcode & 0x00F0) >> 4];
+ V[0xF] = (V[(opcode & 0x00F0) >> 4] > (0xFF - V[(opcode & 0x0F00) >> 8])) ? 1 : 0;
+ break;
+ case 0x0005: // 8XY5 - Sub VY from VX, VF = 0 if there is a borrow
+ V[0xF] = (V[(opcode & 0x00F0) >> 4] > V[(opcode & 0x0F00) >> 8]) ? 0 : 1;
+ V[(opcode & 0x0F00) >> 8] -= V[(opcode & 0x00F0) >> 4];
+ break;
+ case 0x0006: // 8XY6 - Shift VX right by 1. VF = LSB of VX before shift
+ V[0xF] = V[(opcode & 0x0F00) >> 8] & 0x1;
+ V[(opcode & 0x0F00) >> 8] >>= 1;
+ break;
+ case 0x0007: // 8XY7 - Set VX to VY-VX. VF = 0 if there is a borrow
+ V[0xF] = (V[(opcode & 0x0F00) >> 8] > V[(opcode & 0x00F0) >> 4]) ? 0 : 1;
+ V[(opcode & 0x0F00) >> 8] = V[(opcode & 0x00F0) >> 4] - V[(opcode & 0x0F00) >> 8];
+ break;
+ case 0x000E: // 8XYE - Shift VX left by 1. VF = MSB of VX before shift
+ V[0xF] = V[(opcode & 0x0F00) >> 8] >> 7;
+ V[(opcode & 0x0F00) >> 8] <<= 1;
+ break;
+ default:
+ fprintf(stderr, "Unknown opcode: %x\n", opcode);
+ return FALSE;
+ }
+ break;
+ case 0x9000: // 9XY0 - Skip next instruction if VX != VY
+ if (V[(opcode & 0x0F00) >> 8] != V[(opcode & 0x00F0) >> 4]) pc += 2;
+ break;
+ case 0xA000: // ANNN - Set I to the address NNN
+ I = opcode & 0x0FFF;
+ break;
+ case 0xB000: // BNNN - Jump to NNN + V0
+ pc = ((opcode & 0x0FFF) + V[0]) - 2;
+ break;
+ case 0xC000: // CNNN - Set VX to random number masked by NN
+ V[(opcode & 0x0F00) >> 8] = (rand() % (0xFF + 1)) & (opcode & 0x00FF);
+ break;
+ case 0xD000: // Draw an 8 pixel sprite at (VX, VY)
+ {
+ uint8_t VX = V[(opcode & 0x0F00) >> 8];
+ uint8_t VY = V[(opcode & 0x00F0) >> 4];
+ uint16_t h = opcode & 0x000F;
+ uint16_t pixel;
+
+ V[0xF] = 0;
+ int yl, xl;
+ for (yl = 0; yl < h; yl++) {
+ pixel = memory[I + yl];
+ for (xl = 0; xl < 8; xl++) {
+ if ((pixel & (0x80 >> xl)) != 0) {
+ if (gfx[VX + xl + ((VY + yl) * 64)] == 1)
+ V[0xF] = 1;
+ gfx[VX + xl + ((VY + yl) * 64)] ^= 1;
+ }
+ }
+ }
+ drawflag = TRUE;
+ }
+ break;
+ case 0xE000: // EX__
+ switch (opcode & 0x00FF) {
+ case 0x009E: // EX9E - Skip next instruction if key in VX is pressed
+ if (keys[V[(opcode & 0x0F00) >> 8]]) pc += 2;
+ break;
+ case 0x00A1: // EXA1 - Skip next instruction if key in VX isn't pressed
+ if (!keys[V[(opcode & 0x0F00) >> 8]]) pc += 2;
+ break;
+ default:
+ fprintf(stderr, "Unknown opcode: %x\n", opcode);
+ return FALSE;
+ }
+ break;
+ case 0xF000: // FX__
+ switch (opcode & 0x00FF) {
+ case 0x0007: // FX07 - Set VX to delaytimer
+ V[(opcode & 0x0F00) >> 8] = delaytimer;
+ break;
+ case 0x000A: // FX0A - Wait for key press and then store it in VX
+ {
+ int keypressed = FALSE;
+ for (i = 0; i < 16; i++) {
+ if (keys[i]) {
+ V[(opcode & 0x0F00) >> 8] = i;
+ keypressed = TRUE;
+ }
+ }
+ if (!keypressed) return FALSE;
+ }
+ break;
+ case 0x0015: // FX15 - Set the delaytimer to VX
+ delaytimer = V[(opcode & 0x0F00) >> 8];
+ break;
+ case 0x0018: // FX18 - Set the soundtimer to VX
+ soundtimer = V[(opcode & 0x0F00) >> 8];
+ break;
+ case 0x001E: // FX1E - Add VX to I
+ V[0xF] = ((I + V[(opcode & 0x0F00) >> 8]) > 0xFFF) ? 1 : 0;
+ I += V[(opcode & 0x0F00) >> 8];
+ break;
+ case 0x0029: // FX29 - Set I to the location of the sprite for char VX
+ I = V[(opcode & 0x0F00) >> 8] * 0x5;
+ break;
+ case 0x0033: // FX33 - Store bin coded decimal of VX at I, I+1 and I+2
+ memory[I] = V[(opcode & 0x0F00) >> 8] / 100;
+ memory[I+1] = (V[(opcode & 0x0F00) >> 8] / 10) % 10;
+ memory[I+2] = V[(opcode & 0x0F00) >> 8] % 10;
+ break;
+ case 0x0055: // FX55 - Store V0 to VX in memory starting at I
+ for (i = 0; i <= ((opcode & 0x0F00) >> 8); i++)
+ memory[I + i] = V[i];
+ I += ((opcode & 0x0F00) >> 8) + 1;
+ break;
+ case 0x0065: // FX65 - Fill V0 to VX with vals from memory starting at I
+ for (i = 0; i <= ((opcode & 0x0F00) >> 8); i++)
+ V[i] = memory[I + i];
+ I += ((opcode & 0x0F00) >> 8) + 1;
+ break;
+ default:
+ fprintf(stderr, "Unknown opcode: %x\n", opcode);
+ return FALSE;
+ }
+ break;
+ default:
+ fprintf(stderr, "Unimplemented opcode\n");
+ return FALSE;
+ }
+ return TRUE;
+}
+
+void
+timers_update(struct Chip8 *chip8)
+{
+ if (delaytimer > 0) --delaytimer;
+ if (soundtimer > 0) --soundtimer;
+}
+
+#undef V
+#undef pc
+#undef opcode
+#undef I
+#undef sp
+#undef memory
+#undef gfx
+#undef stack
+#undef keys
+#undef delaytimer
+#undef soundtimer
+#undef drawflag
+
+int
+evts(struct Chip8 *chip8)
+{
+ int i;
+ SDL_Event e;
+ while (SDL_PollEvent(&e))
+ {
+ if (e.type == SDL_QUIT || e.key.keysym.sym == SDLK_ESCAPE) return FALSE;
+ if (e.type == SDL_KEYDOWN)
+ for (i = 0; i < 16; i++)
+ if (e.key.keysym.sym == keymap[i])
+ chip8->keys[i] = TRUE;
+ if (e.type == SDL_KEYUP)
+ for (i = 0; i < 16; i++)
+ if (e.key.keysym.sym == keymap[i])
+ chip8->keys[i] = FALSE;
+ }
+ return TRUE;
+}
+
+void
+render(SDL_Renderer *ren, SDL_Texture *tex, struct Chip8 *chip8)
+{
+ int i;
+ uint32_t pixels[2048];
+ chip8->drawflag = FALSE;
+ for (i = 0; i < 2048; i++) {
+ uint8_t pixel = chip8->gfx[i];
+ pixels[i] = (0x00FFFFFF * pixel) | 0xFF000000;
+ }
+ SDL_UpdateTexture(tex, NULL, pixels, 64 * sizeof(Uint32));
+ SDL_RenderClear(ren);
+ SDL_RenderCopy(ren, tex, NULL, NULL);
+ SDL_RenderPresent(ren);
+}
+
+int
+main(int argc, char **argv)
+{
+ int w = 1024, h = 512;
+ srand(time(NULL));
+
+ if (argc != 2) {
+ fprintf(stderr, "Usage: ./chip8 [ROM]\n");
+ return EXIT_FAILURE;
+ }
+ if (SDL_Init(SDL_INIT_EVERYTHING) < 0) {
+ fprintf(stderr, "Cannot initialize SDL. Exiting. . .\n");
+ return EXIT_FAILURE;
+ }
+ SDL_Window *win = SDL_CreateWindow("CHIP-8 Emulator", SDL_WINDOWPOS_UNDEFINED,
+ SDL_WINDOWPOS_UNDEFINED, w, h,
+ SDL_WINDOW_SHOWN);
+ SDL_Renderer *ren = SDL_CreateRenderer(win, -1, 0);
+ SDL_RenderSetLogicalSize(ren, w, h);
+ SDL_Texture *tex = SDL_CreateTexture(ren, SDL_PIXELFORMAT_ARGB8888,
+ SDL_TEXTUREACCESS_STREAMING, 64, 32);
+ if (!win || !ren || !tex) {
+ fprintf(stderr, "SDL error. Exiting. . .\n%s\n", SDL_GetError());
+ return EXIT_FAILURE;
+ }
+
+ struct Chip8 chip8;
+ chip8_init(&chip8);
+ if (!romload(&chip8, argv[1])) return EXIT_FAILURE;
+ for (; evts(&chip8); usleep(1500)) {
+ emulate(&chip8);
+ if (chip8.drawflag) render(ren, tex, &chip8);
+ }
+
+ SDL_DestroyTexture(tex);
+ SDL_DestroyRenderer(ren);
+ SDL_DestroyWindow(win);
+ SDL_Quit();
+ return EXIT_SUCCESS;
+}
diff --git a/src/chip8.c b/src/chip8.c
@@ -1,306 +0,0 @@
-#include "chip8.h"
-
-#define V chip8->V
-#define pc chip8->pc
-#define opcode chip8->opcode
-#define I chip8->I
-#define sp chip8->sp
-#define memory chip8->memory
-#define gfx chip8->gfx
-#define stack chip8->stack
-#define keys chip8->keys
-#define delaytimer chip8->delaytimer
-#define soundtimer chip8->soundtimer
-#define drawflag chip8->drawflag
-
-static int chip8_decode(struct Chip8 *);
-static void chip8_timers_update(struct Chip8 *);
-
-void
-chip8_init(struct Chip8 *chip8)
-{
- uint8_t fontset[80] = {
- 0xF0, 0x90, 0x90, 0x90, 0xF0, // 0
- 0x20, 0x60, 0x20, 0x20, 0x70, // 1
- 0xF0, 0x10, 0xF0, 0x80, 0xF0, // 2
- 0xF0, 0x10, 0xF0, 0x10, 0xF0, // 3
- 0x90, 0x90, 0xF0, 0x10, 0x10, // 4
- 0xF0, 0x80, 0xF0, 0x10, 0xF0, // 5
- 0xF0, 0x80, 0xF0, 0x90, 0xF0, // 6
- 0xF0, 0x10, 0x20, 0x40, 0x40, // 7
- 0xF0, 0x90, 0xF0, 0x90, 0xF0, // 8
- 0xF0, 0x90, 0xF0, 0x10, 0xF0, // 9
- 0xF0, 0x90, 0xF0, 0x90, 0x90, // A
- 0xE0, 0x90, 0xE0, 0x90, 0xE0, // B
- 0xF0, 0x80, 0x80, 0x80, 0xF0, // C
- 0xE0, 0x90, 0x90, 0x90, 0xE0, // D
- 0xF0, 0x80, 0xF0, 0x80, 0xF0, // E
- 0xF0, 0x80, 0xF0, 0x80, 0x80 // F
- };
- pc = 0x200;
- opcode = 0;
- I = 0;
- sp = 0;
- delaytimer = 0;
- soundtimer = 0;
- memset(V, 0, 16 * sizeof(uint8_t));
- memset(keys, 0, 16 * sizeof(uint8_t));
- memset(stack, 0, 16 * sizeof(uint16_t));
- memset(gfx, 0, 2048 * sizeof(uint8_t));
- memset(memory, 0, 4096 * sizeof(uint8_t));
- int i;
- for (i = 0; i < 80; memory[i] = fontset[i], i++);
-}
-
-int
-chip8_rom_load(struct Chip8 *chip8, const char *fpath)
-{
- FILE *rom = fopen(fpath, "rb");
- if (rom == NULL) {
- fprintf(stderr, "Error loading ROM (%s). Exiting. . .\n", fpath);
- return FALSE;
- }
- fseek(rom, 0, SEEK_END);
- long romsize = ftell(rom);
- rewind(rom);
-
- char *buf = (char *)malloc(romsize * sizeof(char));
- if (buf == NULL) {
- fprintf(stderr, "Cannot allocate memory. Exiting. . .\n");
- return FALSE;
- }
-
- size_t res = fread(buf, sizeof(char), (size_t)romsize, rom);
- if (res != romsize) {
- fprintf(stderr, "Error reading ROM. Exiting. . .\n");
- return FALSE;
- }
-
- int i;
- if ((4096 - 512) > romsize)
- for (i = 0; i < romsize; i++)
- memory[i + 512] = (uint8_t)buf[i];
- else {
- fprintf(stderr, "ROM can't fit into memory. Exiting. . .\n");
- return FALSE;
- }
-
- fclose(rom);
- free(buf);
- return TRUE;
-}
-
-void
-chip8_emulate(struct Chip8 *chip8)
-{
- opcode = memory[pc] << 8 | memory[pc + 1]; // fetch
- if (chip8_decode(chip8)) {
- pc += 2; // execute
- chip8_timers_update(chip8);
- }
- printf("Opcode: %x\tMemory: %x\tI: %x\tSP: %x\tPC: %d\n",
- opcode, memory[pc] << 8 | memory[pc + 1], I, sp, pc);
-}
-
-int
-chip8_decode(struct Chip8 *chip8)
-{
- switch (opcode & 0xF000) {
- int i;
- case 0x0000: // 00E_
- switch (opcode & 0x00FF) {
- case 0xE0: // 00E0 - Clear screen
- memset(gfx, 0, 2048 * sizeof(uint8_t));
- drawflag = TRUE;
- break;
- case 0xEE: // 00EE - Return from subroutine
- pc = stack[--sp];
- break;
- default:
- fprintf(stderr, "Unknown opcode: %x\n", opcode);
- return FALSE;
- }
- break;
- case 0x1000: // 1NNN - Jump to address NNN
- pc = (opcode & 0x0FFF) - 2;
- break;
- case 0x2000: // 2NNN - Call subroutine at NNN
- stack[sp++] = pc;
- pc = (opcode & 0x0FFF) - 2;
- case 0x3000: // 3NNN - Skip next instruction if VX == NN
- if (V[(opcode & 0x0F00) >> 8] == (opcode & 0x00FF)) pc += 2;
- break;
- case 0x4000: // 4NNN - Skip next instruction if VX != NN
- if (V[(opcode & 0x0F00) >> 8] != (opcode & 0x00FF)) pc += 2;
- break;
- case 0x5000: // 5XY0 - Skip next instruction if VX == VY
- if (V[(opcode & 0x0F00) >> 8] == V[(opcode & 0x00F0) >> 4]) pc += 2;
- break;
- case 0x6000: // 6XNN - Set VX to NN
- V[(opcode & 0x0F00) >> 8] = opcode & 0x00FF;
- break;
- case 0x7000: // 7XNN - Add NN to VX
- V[(opcode & 0x0F00) >> 8] += opcode & 0x00FF;
- break;
- case 0x8000: // 8XY_
- switch (opcode & 0x000F) {
- case 0x0000: // 8XY0 - Set VX to VY
- V[(opcode & 0x0F00) >> 8] = V[(opcode & 0x00F0) >> 4];
- break;
- case 0x0001: // 8XY1 - Set VX to (VX OR VY)
- V[(opcode & 0x0F00) >> 8] |= V[(opcode & 0x00F0) >> 4];
- break;
- case 0x0002: // 8XY2 - Set VX to (VX AND VY)
- V[(opcode & 0x0F00) >> 8] &= V[(opcode & 0x00F0) >> 4];
- break;
- case 0x0003: // 8XY3 - Set VX to (VX XOR VY)
- V[(opcode & 0x0F00) >> 8] ^= V[(opcode & 0x00F0) >> 4];
- break;
- case 0x0004: // 8XY4 - Add VY to VX, VF = 1 if there is a carry
- V[(opcode & 0x0F00) >> 8] += V[(opcode & 0x00F0) >> 4];
- V[0xF] = (V[(opcode & 0x00F0) >> 4] > (0xFF - V[(opcode & 0x0F00) >> 8])) ? 1 : 0;
- break;
- case 0x0005: // 8XY5 - Sub VY from VX, VF = 0 if there is a borrow
- V[0xF] = (V[(opcode & 0x00F0) >> 4] > V[(opcode & 0x0F00) >> 8]) ? 0 : 1;
- V[(opcode & 0x0F00) >> 8] -= V[(opcode & 0x00F0) >> 4];
- break;
- case 0x0006: // 8XY6 - Shift VX right by 1. VF = LSB of VX before shift
- V[0xF] = V[(opcode & 0x0F00) >> 8] & 0x1;
- V[(opcode & 0x0F00) >> 8] >>= 1;
- break;
- case 0x0007: // 8XY7 - Set VX to VY-VX. VF = 0 if there is a borrow
- V[0xF] = (V[(opcode & 0x0F00) >> 8] > V[(opcode & 0x00F0) >> 4]) ? 0 : 1;
- V[(opcode & 0x0F00) >> 8] = V[(opcode & 0x00F0) >> 4] - V[(opcode & 0x0F00) >> 8];
- break;
- case 0x000E: // 8XYE - Shift VX left by 1. VF = MSB of VX before shift
- V[0xF] = V[(opcode & 0x0F00) >> 8] >> 7;
- V[(opcode & 0x0F00) >> 8] <<= 1;
- break;
- default:
- fprintf(stderr, "Unknown opcode: %x\n", opcode);
- return FALSE;
- }
- break;
- case 0x9000: // 9XY0 - Skip next instruction if VX != VY
- if (V[(opcode & 0x0F00) >> 8] != V[(opcode & 0x00F0) >> 4]) pc += 2;
- break;
- case 0xA000: // ANNN - Set I to the address NNN
- I = opcode & 0x0FFF;
- break;
- case 0xB000: // BNNN - Jump to NNN + V0
- pc = ((opcode & 0x0FFF) + V[0]) - 2;
- break;
- case 0xC000: // CNNN - Set VX to random number masked by NN
- V[(opcode & 0x0F00) >> 8] = (rand() % (0xFF + 1)) & (opcode & 0x00FF);
- break;
- case 0xD000: // Draw an 8 pixel sprite at (VX, VY)
- {
- uint8_t VX = V[(opcode & 0x0F00) >> 8];
- uint8_t VY = V[(opcode & 0x00F0) >> 4];
- uint16_t h = opcode & 0x000F;
- uint16_t pixel;
-
- V[0xF] = 0;
- int yl, xl;
- for (yl = 0; yl < h; yl++) {
- pixel = memory[I + yl];
- for (xl = 0; xl < 8; xl++) {
- if ((pixel & (0x80 >> xl)) != 0) {
- if (gfx[VX + xl + ((VY + yl) * 64)] == 1)
- V[0xF] = 1;
- gfx[VX + xl + ((VY + yl) * 64)] ^= 1;
- }
- }
- }
- drawflag = TRUE;
- }
- break;
- case 0xE000: // EX__
- switch (opcode & 0x00FF) {
- case 0x009E: // EX9E - Skip next instruction if key in VX is pressed
- if (keys[V[(opcode & 0x0F00) >> 8]]) pc += 2;
- break;
- case 0x00A1: // EXA1 - Skip next instruction if key in VX isn't pressed
- if (!keys[V[(opcode & 0x0F00) >> 8]]) pc += 2;
- break;
- default:
- fprintf(stderr, "Unknown opcode: %x\n", opcode);
- return FALSE;
- }
- break;
- case 0xF000: // FX__
- switch (opcode & 0x00FF) {
- case 0x0007: // FX07 - Set VX to delaytimer
- V[(opcode & 0x0F00) >> 8] = delaytimer;
- break;
- case 0x000A: // FX0A - Wait for key press and then store it in VX
- {
- int keypressed = FALSE;
- for (i = 0; i < 16; i++) {
- if (keys[i]) {
- V[(opcode & 0x0F00) >> 8] = i;
- keypressed = TRUE;
- }
- }
- if (!keypressed) return FALSE;
- }
- break;
- case 0x0015: // FX15 - Set the delaytimer to VX
- delaytimer = V[(opcode & 0x0F00) >> 8];
- break;
- case 0x0018: // FX18 - Set the soundtimer to VX
- soundtimer = V[(opcode & 0x0F00) >> 8];
- break;
- case 0x001E: // FX1E - Add VX to I
- V[0xF] = ((I + V[(opcode & 0x0F00) >> 8]) > 0xFFF) ? 1 : 0;
- I += V[(opcode & 0x0F00) >> 8];
- break;
- case 0x0029: // FX29 - Set I to the location of the sprite for char VX
- I = V[(opcode & 0x0F00) >> 8] * 0x5;
- break;
- case 0x0033: // FX33 - Store bin coded decimal of VX at I, I+1 and I+2
- memory[I] = V[(opcode & 0x0F00) >> 8] / 100;
- memory[I+1] = (V[(opcode & 0x0F00) >> 8] / 10) % 10;
- memory[I+2] = V[(opcode & 0x0F00) >> 8] % 10;
- break;
- case 0x0055: // FX55 - Store V0 to VX in memory starting at I
- for (i = 0; i <= ((opcode & 0x0F00) >> 8); i++)
- memory[I + i] = V[i];
- I += ((opcode & 0x0F00) >> 8) + 1;
- break;
- case 0x0065: // FX65 - Fill V0 to VX with vals from memory starting at I
- for (i = 0; i <= ((opcode & 0x0F00) >> 8); i++)
- V[i] = memory[I + i];
- I += ((opcode & 0x0F00) >> 8) + 1;
- break;
- default:
- fprintf(stderr, "Unknown opcode: %x\n", opcode);
- return FALSE;
- }
- break;
- default:
- fprintf(stderr, "Unimplemented opcode\n");
- return FALSE;
- }
- return TRUE;
-}
-
-void
-chip8_timers_update(struct Chip8 *chip8)
-{
- if (delaytimer > 0) --delaytimer;
- if (soundtimer > 0) --soundtimer;
-}
-
-#undef V
-#undef pc
-#undef opcode
-#undef I
-#undef sp
-#undef memory
-#undef gfx
-#undef stack
-#undef keys
-#undef delaytimer
-#undef soundtimer
-#undef drawflag
diff --git a/src/chip8.h b/src/chip8.h
@@ -1,34 +0,0 @@
-#ifndef CHIP8_H
-#define CHIP8_H
-
-#include <inttypes.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <time.h>
-
-#define TRUE 1
-#define FALSE 0
-
-struct Chip8 {
- uint8_t memory[4096];
- uint8_t V[16];
- uint8_t gfx[64 * 32];
- uint8_t keys[16];
- uint8_t delaytimer;
- uint8_t soundtimer;
- uint8_t drawflag;
- uint16_t stack[16];
- uint16_t sp;
- uint16_t opcode;
- uint16_t I;
- uint16_t pc;
-};
-
-extern struct Chip8 chip8;
-
-extern void chip8_init(struct Chip8 *);
-extern int chip8_rom_load(struct Chip8 *, const char *);
-extern void chip8_emulate(struct Chip8 *);
-
-#endif /* CHIP8_H */
diff --git a/src/main.c b/src/main.c
@@ -1,88 +0,0 @@
-#define _DEFAULT_SOURCE
-#include <SDL2/SDL.h>
-#include <unistd.h>
-#include "chip8.h"
-
-static const uint8_t keymap[16] = {
- SDLK_1, SDLK_2, SDLK_3, SDLK_4,
- SDLK_q, SDLK_w, SDLK_e, SDLK_r,
- SDLK_a, SDLK_s, SDLK_d, SDLK_f,
- SDLK_z, SDLK_x, SDLK_c, SDLK_v
-};
-
-static int
-evts(struct Chip8 *chip8)
-{
- int i;
- SDL_Event e;
- while (SDL_PollEvent(&e))
- {
- if (e.type == SDL_QUIT || e.key.keysym.sym == SDLK_ESCAPE) return FALSE;
- if (e.type == SDL_KEYDOWN)
- for (i = 0; i < 16; i++)
- if (e.key.keysym.sym == keymap[i])
- chip8->keys[i] = TRUE;
- if (e.type == SDL_KEYUP)
- for (i = 0; i < 16; i++)
- if (e.key.keysym.sym == keymap[i])
- chip8->keys[i] = FALSE;
- }
- return TRUE;
-}
-
-static void
-render(SDL_Renderer *ren, SDL_Texture *tex, struct Chip8 *chip8)
-{
- int i;
- uint32_t pixels[2048];
- chip8->drawflag = FALSE;
- for (i = 0; i < 2048; i++) {
- uint8_t pixel = chip8->gfx[i];
- pixels[i] = (0x00FFFFFF * pixel) | 0xFF000000;
- }
- SDL_UpdateTexture(tex, NULL, pixels, 64 * sizeof(Uint32));
- SDL_RenderClear(ren);
- SDL_RenderCopy(ren, tex, NULL, NULL);
- SDL_RenderPresent(ren);
-}
-
-int
-main(int argc, char **argv)
-{
- int w = 1024, h = 512;
- srand(time(NULL));
-
- if (argc != 2) {
- fprintf(stderr, "Usage: ./chip8 [ROM]\n");
- return EXIT_FAILURE;
- }
- if (SDL_Init(SDL_INIT_EVERYTHING) < 0) {
- fprintf(stderr, "Cannot initialize SDL. Exiting. . .\n");
- return EXIT_FAILURE;
- }
- SDL_Window *win = SDL_CreateWindow("CHIP-8 Emulator", SDL_WINDOWPOS_UNDEFINED,
- SDL_WINDOWPOS_UNDEFINED, w, h,
- SDL_WINDOW_SHOWN);
- SDL_Renderer *ren = SDL_CreateRenderer(win, -1, 0);
- SDL_RenderSetLogicalSize(ren, w, h);
- SDL_Texture *tex = SDL_CreateTexture(ren, SDL_PIXELFORMAT_ARGB8888,
- SDL_TEXTUREACCESS_STREAMING, 64, 32);
- if (!win || !ren || !tex) {
- fprintf(stderr, "SDL error. Exiting. . .\n%s\n", SDL_GetError());
- return EXIT_FAILURE;
- }
-
- struct Chip8 chip8;
- chip8_init(&chip8);
- if (!chip8_rom_load(&chip8, argv[1])) return EXIT_FAILURE;
- for (; evts(&chip8); usleep(1500)) {
- chip8_emulate(&chip8);
- if (chip8.drawflag) render(ren, tex, &chip8);
- }
-
- SDL_DestroyTexture(tex);
- SDL_DestroyRenderer(ren);
- SDL_DestroyWindow(win);
- SDL_Quit();
- return EXIT_SUCCESS;
-}
