def test_set_x_to_delay_timer(self):
opcode = Opcode(0xF207)
operation = SetXToDelayTimer()
self.cpu.delay_timer = 0xA
operation.execute(opcode, self.cpu)
self.assertEqual(self.cpu.general_purpose_registers[opcode.x],
self.cpu.delay_timer)
def _test_skip(self, word, operation):
opcode = Opcode(word)
operation.execute(opcode, self.cpu)
self.assertEqual(self.cpu.program_counter, Cpu.PROGRAM_START_ADDRESS)
self.cpu.general_purpose_registers[1] = 1
operation.execute(opcode, self.cpu)
self.assertEqual(self.cpu.program_counter,
Cpu.PROGRAM_START_ADDRESS + Cpu.WORD_SIZE_IN_BYTES)
def test_load_character_addresses(self):
operation = LoadCharacterAddress()
for number in range(16):
opcode = Opcode(0xF029)
self.cpu.general_purpose_registers[opcode.x] = number
operation.execute(opcode, self.cpu)
self.assertEqual(self.cpu.index_register,
number * Font.CHAR_SIZE_IN_BYTES)
def test_shift_x_right(self):
opcode = Opcode(0x810E)
operation = ShiftXRight()
self.cpu.general_purpose_registers[opcode.x] = 2
operation.execute(opcode, self.cpu)
self.assertEqual(
self.cpu.general_purpose_registers[
Cpu.ARITHMETIC_FLAG_REGISTER_ADDRESS], 0)
self.assertEqual(self.cpu.general_purpose_registers[opcode.x], 1)
def test_clear_display(self):
opcode = Opcode(0x00E0)
operation = ClearDisplay()
operation.execute(opcode, self.cpu)
for x in range(64):
for y in range(32):
self.assertEqual(self.cpu.frame_buffer[x][y], False)
def test_call_function(self):
opcode = Opcode(0x2ABC)
operation = CallFunction()
operation.execute(opcode, self.cpu)
self.assertEqual(self.cpu.program_counter, 0xABC)
self.assertEqual(len(self.cpu.stack), 1)
self.assertEqual(self.cpu.stack[0], 512)
def _test_arithmetic(self, word, operation, x, y, expected_result,
expected_flag_value):
opcode = Opcode(word)
self.cpu.general_purpose_registers[opcode.x] = x
self.cpu.general_purpose_registers[opcode.y] = y
operation.execute(opcode, self.cpu)
self.assertEqual(self.cpu.general_purpose_registers[opcode.x],
expected_result)
self.assertEqual(
self.cpu.general_purpose_registers[
Cpu.ARITHMETIC_FLAG_REGISTER_ADDRESS], expected_flag_value)
def test_skip_if_key_not_down(self):
opcode = Opcode(0xE4A1)
self.cpu.general_purpose_registers[opcode.x] = 0xF
operation = SkipIfKeyNotPressed()
self.cpu.key_down(0xF)
operation.execute(opcode, self.cpu)
self.assertEqual(self.cpu.program_counter,
self.cpu.PROGRAM_START_ADDRESS)
self.cpu.key_up(0xF)
operation.execute(opcode, self.cpu)
self.assertEqual(
self.cpu.program_counter,
self.cpu.PROGRAM_START_ADDRESS + self.cpu.WORD_SIZE_IN_BYTES)
def test_draw_collision(self):
opcode = Opcode(0xD113)
x = self.cpu.general_purpose_registers[opcode.x]
y = self.cpu.general_purpose_registers[opcode.y]
self.cpu.ram[self.cpu.index_register] = 0b1111
operation = DrawSprite()
operation.execute(opcode, self.cpu)
self.assertEqual(self.cpu.general_purpose_registers[self.cpu.ARITHMETIC_FLAG_REGISTER_ADDRESS], 0)
self.cpu.ram[self.cpu.index_register] = 0b0110
operation.execute(opcode, self.cpu)
self._test_buffer_pixels_match_pattern(x, y, 0b1001)
self.assertEqual(self.cpu.general_purpose_registers[self.cpu.ARITHMETIC_FLAG_REGISTER_ADDRESS], 1)
def test_wait_for_key_press(self):
opcode = Opcode(0xF10A)
operation = WaitForKeyPress()
program_address = self.cpu.program_counter
operation.execute(opcode, self.cpu)
self.cpu.move_to_next_instruction()
self.assertEqual(self.cpu.general_purpose_registers[opcode.x], 0x0)
self.assertEqual(self.cpu.program_counter, program_address)
self.cpu.key_down(0xE)
operation.execute(opcode, self.cpu)
self.cpu.move_to_next_instruction()
self.assertEqual(self.cpu.general_purpose_registers[opcode.x], 0xE)
self.assertGreater(self.cpu.program_counter, program_address)
self.assertEqual(self.cpu.program_counter - program_address,
self.cpu.WORD_SIZE_IN_BYTES)
def test_draw_sprite(self):
opcode = Opcode(0xD013)
self.cpu.general_purpose_registers[opcode.x] = 0
self.cpu.general_purpose_registers[opcode.y] = 1
self.cpu.ram[self.cpu.index_register] = 0b1
self.cpu.ram[self.cpu.index_register + 1] = 0b11
self.cpu.ram[self.cpu.index_register + 2] = 0b111
operation = DrawSprite()
operation.execute(opcode, self.cpu)
x = self.cpu.general_purpose_registers[opcode.x]
y = self.cpu.general_purpose_registers[opcode.y]
self._test_buffer_pixels_match_pattern(x, y, 0b1)
self._test_buffer_pixels_match_pattern(x, y+1, 0b11)
self._test_buffer_pixels_match_pattern(x, y+2, 0b111)
self._test_buffer_pixels_match_pattern(x, y+3, 0b0)
def find_operation(self, word):
"This method takes a 16 bit value representing an opcode and returns the related operation"
opcode = Opcode(word)
# make a key of a + n + n so that 0xA123 becomes 0xA23
twelve_bit_key = int((opcode.a << 8) + opcode.nn)
if twelve_bit_key in self._operations:
return self._operations[twelve_bit_key]
# make a key of a + n so that 0xA123 becomes 0xA3
eight_bit_key = int((opcode.a << 4) + opcode.n)
if eight_bit_key in self._operations:
return self._operations[eight_bit_key]
four_bit_key = opcode.a
if four_bit_key in self._operations:
return self._operations[four_bit_key]
raise KeyError(
f"Opcode {word:#06x} not present in list of valid operations")
def setUp(self):
self.opcode = Opcode(0xABCD)
self.operation_mapper = OperationMapper()
def setUp(self):
self.opcode = Opcode(0xABCD)
def _test_bitwise_operation(self, word, operation, expected_value):
opcode = Opcode(word)
operation.execute(opcode, self.cpu)
self.assertEqual(self.cpu.general_purpose_registers[opcode.x],
expected_value)
