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const std = @import("std");
const ray = @import("raylib.zig");
//const ray = @cImport({
// @cInclude("raylib.h");
//});
const print = std.debug.print;
const fs = std.fs;
const screenWidth: u32 = 64 * 10;
const screenHeight: u32 = (32 * 10) + 24;
const RndGen = std.rand.DefaultPrng;
var Rnd = RndGen.init(0);
var chip8_screen: ray.RenderTexture = undefined;
const Chip8 = struct {
opcode: u16 = 0,
memory: [4096]u8 = [_]u8{0} ** 4096,
V: [16]u8 = [_]u8{0} ** 16,
I: u16 = 0,
pc: u16 = 0x200,
gfx: [64 * 32]bool = [_]bool{false} ** (64 * 32),
delay_timer: u8 = 0,
sound_timer: u8 = 0,
stack: [16]u16 = [_]u16{0} ** 16,
sp: u16 = 0,
key: u8 = 0,
pub fn new() Chip8 {
// TODO Initialize registers and memory once
return Chip8{};
}
pub fn load_game(self: *Chip8, file_name: []const u8) void {
const file = std.fs.cwd().openFile(file_name, .{ .mode = .read_write }) catch |err| {
print("{}\n", .{err});
return;
};
defer file.close();
var buf: [512 * 7]u8 = undefined;
const chars_read = file.readAll(&buf) catch |err| {
print("{}\n", .{err});
return;
};
print("{s}\n", .{buf});
var length: u32 = 0;
for (buf) |char, index| {
if (index == chars_read) {
break;
}
//print("{}: {x}\n", .{ index, char });
self.*.memory[index + 512] = char;
length += 1;
}
length = (length + 514) / 2;
var iter: u32 = 510 / 2;
while (iter < length) {
defer iter += 1;
print("{}, {}: {x:0>4}\n", .{ iter * 2, iter * 2 + 1, @intCast(u16, self.*.memory[iter * 2]) << 8 | self.*.memory[iter * 2 + 1] });
}
print("\n\n", .{});
}
pub fn emulate_cycles(self: *Chip8, cycles: u32) void {
var i: u32 = cycles;
while (i > 0) : (i -= 1) {
// Fetch Opcode
self.*.opcode = @intCast(u16, self.*.memory[self.*.pc]) << 8 | self.*.memory[self.*.pc + 1];
// Decode Opcode
// Execute Opcode
switch (self.*.opcode & 0xF000) {
0x0000 => { // 00E0: Clear Screen
print("{x:0>4} - Clear Screen\n", .{self.*.opcode});
self.*.gfx = [_]bool{false} ** (64 * 32);
self.*.pc += 2;
print("\n", .{});
},
0x1000 => { // 1NNN: Jump to NNN
print("{x:0>4} - Jump to 1NNN\n", .{self.*.opcode});
//self.*.stack[self.*.sp] = self.*.pc;
self.*.pc = @intCast(u12, self.*.opcode & 0x0FFF);
print("\n", .{});
},
0x6000 => { // 6XNN: Set VX to NN
print("{x:0>4} - Set VX to 6XNN\n", .{self.*.opcode});
self.*.V[(self.*.opcode & 0x0F00) >> 8] = @intCast(u8, self.*.opcode & 0x00FF);
print("set V{x:0>4} to {x:0>4}\n", .{ (self.*.opcode & 0x0F00) >> 8, @intCast(u8, self.*.opcode & 0x00FF) });
self.*.pc += 2;
print("\n", .{});
},
0x7000 => { // 7XNN: Add NN to VX (dont change carry flag)
print("{x:0>4} - Add 7XNN to VX\n", .{self.*.opcode});
self.*.V[(self.*.opcode & 0x0F00) >> 8] += @intCast(u8, self.*.opcode & 0x00FF);
self.*.pc += 2;
print("\n", .{});
},
0xA000 => { // ANNN: Set I to adress NNN
print("{x:0>4} - Set I to ANNN\n", .{self.*.opcode});
self.*.I = self.*.opcode & 0x0FFF;
print("Wrote {x:0>4} to I\n", .{self.*.opcode & 0x0FFF});
print("Check: {x:0>4}\n", .{self.*.I});
self.*.pc += 2;
print("\n", .{});
},
0xD000 => { // DXYN: Draw a sprite
print("{x:0>4} - Draw Sprite DXYN\n", .{self.*.opcode});
const x: u16 = self.*.V[(self.*.opcode & 0x0F00) >> 8];
const y: u16 = self.*.V[(self.*.opcode & 0x00F0) >> 4];
const height: u16 = self.*.opcode & 0x000F;
var pixel: u16 = undefined;
print("Opcode x:{x:0>4}\n", .{(self.*.opcode & 0x0F00)});
print("Opcode y:{x:0>4}\n", .{(self.*.opcode & 0x00F0)});
print("Vx:{x:0>4}\n", .{((self.*.opcode & 0x0F00) >> 8)});
print("Vy:{x:0>4}\n", .{((self.*.opcode & 0x00F0) >> 4)});
//print("x: {x}\ny: {x}\n\n", .{ x, y });
//print("x: {x}\ny: {x}\n\n", .{
// @intCast(u16, self.*.opcode & 0x0F00 >> 8),
// @intCast(u16, self.*.opcode & 0x00F0 >> 4),
//});
//for (self.*.V) |v| {
//print("{x} ", .{v});
//}
//print("\n", .{});
self.*.V[0xF] = 0;
var yline: u32 = 0;
while (yline < height) {
defer yline += 1;
pixel = self.*.memory[self.*.I + yline];
var xline: u32 = 0;
while (xline < 8) {
defer xline += 1;
//while (times(&eight)) |width| {
if ((pixel & (@intCast(u32, 0x80) >> @intCast(u5, xline))) != 0) {
if (self.*.gfx[(x + xline + ((y + yline) * 64))] == true) {
self.*.V[0xF] = 1;
}
self.*.gfx[x + xline + ((y + yline) * 64)] = true;
}
}
}
self.*.pc += 2;
print("\n", .{});
},
else => {
// opcode not found
print("{x:0>4} - OPCODE NOT FOUND\n", .{self.*.opcode});
print("\n", .{});
},
}
// Update timers
_ = self;
}
}
};
var chip8 = Chip8.new();
pub fn main() !void {
setup_graphics();
defer ray.CloseWindow();
var exitWindow: bool = false;
chip8.load_game("roms/IBM_Logo.ch8");
while (!ray.WindowShouldClose() and !exitWindow) {
ray.BeginDrawing();
defer ray.EndDrawing();
exitWindow = ray.GuiWindowBox(ray.Rectangle{ .x = 0, .y = 0, .height = screenHeight, .width = screenWidth }, "CHIP-8");
chip8.emulate_cycles(1);
update_screen(&chip8_screen, chip8.gfx);
}
}
fn pow(base: u32, power: u32) u32 {
var iter: u32 = 0;
var result: u32 = base;
while (iter < power) : (iter += 1) {
result = result * base;
}
return result;
}
fn get_coords(x: u32, y: u32) u32 {
return y * 64 + x;
}
fn setup_graphics() void {
//for (chip8_screen) |*pixel, index_usize| {
// var index: u32 = @intCast(u32, index_usize);
// pixel.* = chip8_pixel{ .location = ray.Rectangle{ .x = 10 * @intToFloat(f32, @mod(index, 64)), .y = 24 + 10 * @intToFloat(f32, (index / 64)), .width = 10, .height = 10 } };
//}
ray.InitWindow(screenWidth, screenHeight, "raylib [core] example - basic window");
chip8_screen = ray.LoadRenderTexture(64, 32);
ray.SetTargetFPS(6);
}
fn update_screen(screen: *ray.RenderTexture, pixels: [2048]bool) void {
ray.ClearBackground(ray.RAYWHITE);
ray.BeginTextureMode(screen.*);
for (pixels) |pixel, index_usize| {
//var rnd: u8 = Rnd.random().int(u8);
//if (rnd < (256 / 2)) {
// rnd = 255;
//} else {
// rnd = 0;
//}
var on: u8 = undefined;
if (pixel) {
on = 255;
} else {
on = 0;
}
var index: u32 = @intCast(u32, index_usize);
//var index_char: u8 = @intCast(u8, @mod(@intCast(u32, index_usize), 256));
ray.DrawRectangleRec(ray.Rectangle{ .x = @intToFloat(f32, @mod(index, 64)), .y = @intToFloat(f32, (index / 64)), .width = 1, .height = 1 }, ray.Color{ .r = on, .g = on, .b = on, .a = 255 });
}
ray.EndTextureMode();
ray.DrawTextureEx(screen.texture, ray.Vector2{ .x = 0, .y = 24 }, 0, 10, ray.WHITE);
}
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