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zern/examples/chip8.zr

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// needs to be compiled with -m -C="-lraylib"
extern InitWindow
extern SetTargetFPS
extern WindowShouldClose
extern BeginDrawing
extern ClearBackground
extern DrawRectangle
extern EndDrawing
extern IsKeyDown
struct CHIP8
memory: ptr
pc: i64
stack: array
sp: i64
reg: ptr
I: i64
delay_timer: i64
sound_timer: i64
keyboard: array
display: ptr
keyboard_map: array
func chip8_create[] : CHIP8
let c: CHIP8 = new CHIP8
c->memory = mem.alloc(4096)
mem.zero(c->memory, 4096)
c->display = mem.alloc(64*32)
mem.zero(c->display, 64*32)
c->reg = mem.alloc(16)
mem.zero(c->reg, 16)
c->stack = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
c->keyboard = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
let fonts: array = [0xf0, 0x90, 0x90, 0x90, 0xf0, 0x20, 0x60, 0x20, 0x20, 0x70, 0xf0, 0x10, 0xf0, 0x80, 0xf0, 0xf0, 0x10, 0xf0, 0x10, 0xf0, 0x90, 0x90, 0xf0, 0x10, 0x10, 0xf0, 0x80, 0xf0, 0x10, 0xf0, 0xf0, 0x80, 0xf0, 0x90, 0xf0, 0xf0, 0x10, 0x20, 0x40, 0x40, 0xf0, 0x90, 0xf0, 0x90, 0xf0, 0xf0, 0x90, 0xf0, 0x10, 0xf0, 0xf0, 0x90, 0xf0, 0x90, 0x90, 0xe0, 0x90, 0xe0, 0x90, 0xe0, 0xf0, 0x80, 0x80, 0x80, 0xf0, 0xe0, 0x90, 0x90, 0x90, 0xe0, 0xf0, 0x80, 0xf0, 0x80, 0xf0, 0xf0, 0x80, 0xf0, 0x80, 0x80]
for i in 0..80
c->memory[i] = array.nth(fonts, i)
mem.free(fonts)
c->pc = 0x200
// see KeyboardKey in raylib.h
c->keyboard_map = [49, 50, 51, 52, 53, 265, 32, 263, 264, 262, 87, 69, 82, 84, 89, 85]
return c
func chip8_disassemble[c: CHIP8, ins_count: i64] : void
for i in 0..ins_count
io.print("0x")
io.print_i64_hex(c->pc)
io.print(": ")
let high: i64 = c->memory[c->pc]
let low: i64 = c->memory[c->pc + 1]
c->pc = c->pc + 2
let ins: i64 = (high << 8) | low
let nnn: i64 = ins & 0x0fff
let kk: i64 = ins & 0x00ff
let n: i64 = ins & 0x000f
let x: i64 = (ins >> 8) & 0x0f
let y: i64 = (ins >> 4) & 0x0f
let op: i64 = (ins >> 12) & 0x0f
if op == 0x0
if nnn == 0x0e0
io.println("CLS")
else if nnn == 0x0ee
io.println("RET")
else
io.print("SYS ")
io.println_i64(nnn)
else if op == 0x1
io.print("JP 0x")
io.print_i64_hex(nnn)
io.print("\n")
else if op == 0x2
io.print("CALL ")
io.println_i64(nnn)
else if op == 0x3
io.print("SE V")
io.print_i64_hex(x)
io.print(", ")
io.println_i64(kk)
else if op == 0x4
io.print("SNE V")
io.print_i64_hex(x)
io.print(", ")
io.println_i64(kk)
else if op == 0x5
io.print("SE V")
io.print_i64_hex(x)
io.print(", V")
io.print_i64_hex(y)
io.print("\n")
else if op == 0x6
io.print("LD V")
io.print_i64_hex(x)
io.print(", ")
io.println_i64(kk)
else if op == 0x7
io.print("ADD V")
io.print_i64_hex(x)
io.print(", ")
io.println_i64(kk)
else if op == 0x8
if n == 0x0
io.print("LD V")
io.print_i64_hex(x)
io.print(", V")
io.print_i64_hex(y)
io.print("\n")
else if n == 0x1
io.print("OR V")
io.print_i64_hex(x)
io.print(", V")
io.print_i64_hex(y)
io.print("\n")
else if n == 0x2
io.print("AND V")
io.print_i64_hex(x)
io.print(", V")
io.print_i64_hex(y)
io.print("\n")
else if n == 0x3
io.print("XOR V")
io.print_i64_hex(x)
io.print(", V")
io.print_i64_hex(y)
io.print("\n")
else if n == 0x4
io.print("ADD V")
io.print_i64_hex(x)
io.print(", V")
io.print_i64_hex(y)
io.print("\n")
else if n == 0x5
io.print("SUB V")
io.print_i64_hex(x)
io.print(", V")
io.print_i64_hex(y)
io.print("\n")
else if n == 0x6
io.print("SHR V")
io.print_i64_hex(x)
io.print("\n")
else if n == 0x7
io.print("SUBN V")
io.print_i64_hex(x)
io.print(", V")
io.print_i64_hex(y)
io.print("\n")
else if n == 0xE
io.print("SHL V")
io.print_i64_hex(x)
io.print("\n")
else
io.print("??? (")
io.print_i64_hex(ins)
io.println(")")
else if op == 0x9
io.print("SNE V")
io.print_i64_hex(x)
io.print(", V")
io.print_i64_hex(y)
io.print("\n")
else if op == 0xa
io.print("LD I, 0x")
io.print_i64_hex(nnn)
io.print("\n")
else if op == 0xb
io.print("JP V0, ")
io.println_i64(nnn)
else if op == 0xc
io.print("RND V")
io.print_i64_hex(x)
io.print(", ")
io.println_i64(kk)
else if op == 0xd
io.print("DRW V")
io.print_i64_hex(x)
io.print(", V")
io.print_i64_hex(y)
io.print(", ")
io.println_i64(n)
else if op == 0xe
if kk == 0x9e
io.print("SKP V")
io.print_i64_hex(x)
io.print("\n")
else if kk == 0xa1
io.print("SKNP V")
io.print_i64_hex(x)
io.print("\n")
else
io.print("??? (")
io.print_i64_hex(ins)
io.println(")")
else if op == 0xf
if kk == 0x07
io.print("LD V")
io.print_i64_hex(x)
io.println(", DT")
else if kk == 0x0A
io.print("LD V")
io.print_i64_hex(x)
io.println(", K")
else if kk == 0x15
io.print("LD DT, V")
io.print_i64_hex(x)
io.print("\n")
else if kk == 0x18
io.print("LD ST, V")
io.print_i64_hex(x)
io.print("\n")
else if kk == 0x1E
io.print("ADD I, V")
io.print_i64_hex(x)
io.print("\n")
else if kk == 0x29
io.print("LD F, V")
io.print_i64_hex(x)
io.print("\n")
else if kk == 0x33
io.print("LD B, V")
io.print_i64_hex(x)
io.print("\n")
else if kk == 0x55
io.print("LD [I], V")
io.print_i64_hex(x)
io.print("\n")
else if kk == 0x65
io.print("LD V")
io.print_i64_hex(x)
io.println(", [I]")
else
io.print("??? (")
io.print_i64_hex(ins)
io.println(")")
else
io.print("??? (")
io.print_i64_hex(ins)
io.println(")")
func chip8_step[c: CHIP8] : void
let high: i64 = c->memory[c->pc]
let low: i64 = c->memory[c->pc + 1]
c->pc = c->pc + 2
let ins: i64 = (high << 8) | low
let nnn: i64 = ins & 0x0fff
let kk: i64 = ins & 0x00ff
let n: i64 = ins & 0x000f
let x: i64 = (ins >> 8) & 0x0f
let y: i64 = (ins >> 4) & 0x0f
let op: i64 = (ins >> 12) & 0x0f
if op == 0x0
if nnn == 0x0e0
mem.zero(c->display, 64 * 32)
else if nnn == 0x0ee
c->pc = array.nth(c->stack, c->sp)
c->sp = c->sp - 1
else if op == 0x1
c->pc = nnn
else if op == 0x2
c->sp = c->sp + 1
array.set(c->stack, c->sp, c->pc)
c->pc = nnn
else if op == 0x3
if c->reg[x] == kk
c->pc = c->pc + 2
else if op == 0x4
if c->reg[x] != kk
c->pc = c->pc + 2
else if op == 0x5
if c->reg[x] == c->reg[y]
c->pc = c->pc + 2
else if op == 0x6
c->reg[x] = kk
else if op == 0x7
c->reg[x] = c->reg[x] + kk
else if op == 0x8
if n == 0x0
c->reg[x] = c->reg[y]
else if n == 0x1
c->reg[x] = c->reg[x] | c->reg[y]
else if n == 0x2
c->reg[x] = c->reg[x] & c->reg[y]
else if n == 0x3
c->reg[x] = c->reg[x] ^ c->reg[y]
else if n == 0x4
let res: i64 = c->reg[x] + c->reg[y]
c->reg[0xf] = res > 0xff
c->reg[x] = res
else if n == 0x5
c->reg[0xf] = c->reg[x] > c->reg[y]
c->reg[x] = c->reg[x] - c->reg[y]
else if n == 0x6
c->reg[0xf] = c->reg[x] & 0x1
c->reg[x] = c->reg[x] >> 1
else if n == 0x7
c->reg[0xf] = c->reg[y] > c->reg[x]
c->reg[x] = c->reg[y] - c->reg[x]
else if n == 0xE
c->reg[0xf] = (c->reg[x] & 0x80) >> 7
c->reg[x] = c->reg[x] << 1
else if op == 0x9
if c->reg[x] != c->reg[y]
c->pc = c->pc + 2
else if op == 0xa
c->I = nnn
else if op == 0xb
c->pc = nnn + c->reg[0]
else if op == 0xc
c->reg[x] = (math.floor(os.urandom_i64()) % 256) & kk
else if op == 0xd
c->reg[0xf] = 0
for row in 0..n
for col in 0..8
if (c->memory[c->I + row] & (0x80 >> col)) != 0
let pixel_x: i64 = (c->reg[x] + col) % 64
let pixel_y: i64 = (c->reg[y] + row) % 32
let offset: i64 = pixel_x + (pixel_y * 64)
if c->display[offset] == 1
c->reg[0xf] = 1
c->display[offset] = c->display[offset] ^ 1
else if op == 0xe
if kk == 0x9e
if IsKeyDown(array.nth(c->keyboard_map, c->reg[x]))
c->pc = c->pc + 2
else if kk == 0xa1
if !IsKeyDown(array.nth(c->keyboard_map, c->reg[x]))
c->pc = c->pc + 2
else if op == 0xf
if kk == 0x07
c->reg[x] = c->delay_timer
else if kk == 0x0A
let key_pressed: bool = false
while !key_pressed && !WindowShouldClose()
for i in 0..16
if IsKeyDown(array.nth(c->keyboard_map, i))
key_pressed = true
break
else if kk == 0x15
c->delay_timer = c->reg[x]
else if kk == 0x18
c->sound_timer = c->reg[x]
else if kk == 0x1E
c->I = c->I + c->reg[x]
else if kk == 0x29
c->I = c->reg[x] * 5
else if kk == 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
else if kk == 0x55
for i in 0..x+1
c->memory[c->I + i] = c->reg[i]
else if kk == 0x65
for i in 0..x+1
c->reg[i] = c->memory[c->I + i]
func chip8_free[c: CHIP8] : void
mem.free(c->memory)
array.free(c->stack)
mem.free(c->reg)
array.free(c->keyboard)
mem.free(c->display)
array.free(c->keyboard_map)
mem.free(c)
func main[argc: i64, argv: ptr] : i64
let path: str = 0
let disassemble: bool = 0
for i in 1..argc
let arg: str = mem.read64(argv + i * 8)
if str.equal(arg, "-d")
disassemble = 1
else
path = arg
if path == 0
io.println("Usage: chip8 -d <path>")
return 1
let c: CHIP8 = chip8_create()
let bytes_size: ptr = 0
let bytes: ptr = io.read_binary_file(path, ^bytes_size)
for i in 0..bytes_size
c->memory[0x200 + i] = bytes[i]
if disassemble
chip8_disassemble(c, bytes_size / 2)
return 0
InitWindow(640, 320, "CHIP-8")
SetTargetFPS(60)
while !WindowShouldClose()
if c->delay_timer > 0
c->delay_timer = c->delay_timer - 1
if c->sound_timer > 0
c->sound_timer = c->sound_timer - 1
// TODO: buzzer
for i in 0..25
chip8_step(c)
BeginDrawing()
ClearBackground(0xffffffff)
for y in 0..32
for x in 0..64
if c->display[x + y * 64] == 1
DrawRectangle(x * 10, y * 10, 10, 10, 0xff000000)
EndDrawing()