def test_execute_iny_255_to_0():
opcode = OpCode()
registers = Registers()
registers.y_index = 0xff
opcode.execute(0xC8, registers, None)
assert registers.y_index == 0
assert registers.negative_flag == False
assert registers.zero_flag
def test_execute_dey_128_to_127():
opcode = OpCode()
registers = Registers()
registers.y_index = 0x80
opcode.execute(0x88, registers, None)
assert registers.y_index == 0x7f
assert registers.negative_flag == False
assert registers.zero_flag == False
def test_execute_dey_0_to_minus1():
opcode = OpCode()
registers = Registers()
registers.y_index = 0
opcode.execute(0x88, registers, None)
assert registers.y_index == 255
assert registers.negative_flag
assert registers.zero_flag == False
def test_execute_iny_127_to_128():
opcode = OpCode()
registers = Registers()
dummy_value = 0x7f
registers.y_index = dummy_value
opcode.execute(0xC8, registers, None)
assert registers.y_index == dummy_value + 1
assert registers.negative_flag
assert registers.zero_flag == False
def test_execute_nop():
opcode = OpCode()
registers = Registers()
with patch.object(MemoryController, 'read',
return_value=None) as mock_memory_controller:
count = opcode.execute(0xEA, registers, mock_memory_controller)
assert count == 2
mock_memory_controller.assert_not_called()
assert registers == Registers()
def test_execute_dey_1_to_0():
opcode = OpCode()
registers = Registers()
registers.y_index = 1
with patch.object(MemoryController, 'read',
return_value=None) as mock_memory_controller:
count = opcode.execute(0x88, registers, mock_memory_controller)
assert count == 2
mock_memory_controller.assert_not_called()
assert registers.y_index == 0
assert registers.negative_flag == False
assert registers.zero_flag
def test_execute_jmp_absolute():
opcode = OpCode()
registers = Registers()
with patch.object(MemoryController, 'read') as mock_memory_controller:
mock_memory_controller.read.side_effect = [0x00, 0xc0]
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(0x4C, registers, mock_memory_controller)
assert count == 3
# Tested more thoroughly in addressing_modes_tests
assert mock_memory_controller.read.call_count == 2
assert registers.pc == 0xc000
def test_execute_iny_0_to_1():
opcode = OpCode()
registers = Registers()
dummy_value = 0x0
registers.y_index = dummy_value
with patch.object(MemoryController, 'read',
return_value=None) as mock_memory_controller:
count = opcode.execute(0xC8, registers, mock_memory_controller)
assert count == 2
mock_memory_controller.assert_not_called()
assert registers.y_index == dummy_value + 1
assert registers.negative_flag == False
assert registers.zero_flag == False
def test_execute_tsx():
opcode = OpCode()
registers = Registers() # leave sp with default
old_sp = registers.sp
with patch.object(MemoryController, 'read',
return_value=None) as mock_memory_controller:
count = opcode.execute(0xBA, registers, mock_memory_controller)
assert count == 2
mock_memory_controller.assert_not_called()
assert registers.x_index == old_sp
assert registers.sp == old_sp
assert registers.negative_flag # default sp should be $fd
assert registers.zero_flag == False
def test_execute_tya():
opcode = OpCode()
registers = Registers()
dummy_value = 0x7c # (positive, not zero)
registers.y_index = dummy_value
with patch.object(MemoryController, 'read',
return_value=None) as mock_memory_controller:
count = opcode.execute(0x98, registers, mock_memory_controller)
assert count == 2
mock_memory_controller.assert_not_called()
assert registers.y_index == dummy_value
assert registers.accumulator == registers.y_index
assert registers.negative_flag == False
assert registers.zero_flag == False
def execute_inc_positive(actual_opcode, expected_clocks, pc_value,
mock_memory_controller, **kwargs):
opcode = OpCode()
registers = Registers()
if kwargs:
for arg in kwargs:
setattr(registers, arg, kwargs[arg])
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(actual_opcode, registers, mock_memory_controller)
assert count == expected_clocks
assert registers.pc == pc_value
assert registers.zero_flag == False
assert registers.negative_flag == False
def test_execute_txs():
opcode = OpCode()
registers = Registers()
dummy_value = 0x7c # (positive, not zero)
registers.x_index = dummy_value
with patch.object(MemoryController, 'read',
return_value=None) as mock_memory_controller:
count = opcode.execute(0x9A, registers, mock_memory_controller)
assert count == 2
mock_memory_controller.assert_not_called()
assert registers.x_index == dummy_value
assert registers.sp == dummy_value
assert registers.negative_flag == False # default sp should be $fd
assert registers.zero_flag == False
def test_execute_bvs_branch_taken():
opcode = OpCode()
registers = Registers()
registers.overflow_flag = True
registers.pc = 0xc000
with patch.object(MemoryController, 'read') as mock_memory_controller:
mock_memory_controller.read.side_effect = [0xfe]
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(0x70, registers, mock_memory_controller)
assert count == 3
# Tested more thoroughly in addressing_modes_tests
assert mock_memory_controller.read.call_count == 1
assert registers.pc == 0xc000
def test_execute_bmi_branch_not_taken():
opcode = OpCode()
registers = Registers()
registers.negative_flag = False
registers.pc = 0xc000
with patch.object(MemoryController, 'read') as mock_memory_controller:
mock_memory_controller.read.side_effect = [0x02]
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(0x30, registers, mock_memory_controller)
assert count == 2
# Tested more thoroughly in addressing_modes_tests
assert mock_memory_controller.read.call_count == 1
assert registers.pc == 0xc002
def test_execute_sta_zeropage():
opcode = OpCode()
registers = Registers()
registers.accumulator = 3
mock_memory_controller = Mock()
# we're mocking 0x85 0x21
mock_memory_controller.read.side_effect = [0x21]
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(0x85, registers, mock_memory_controller)
assert count == 3
assert mock_memory_controller.read.call_count == 1
assert mock_memory_controller.read.call_args_list[0] == unittest.mock.call(
1)
mock_memory_controller.write.assert_called_with(0x21, 3)
assert registers.pc == 2
def test_execute_ldx_immediate_zero():
opcode = OpCode()
registers = Registers()
registers.zero_flag = False
registers.negative_flag = True
with patch.object(MemoryController, 'read') as mock_memory_controller:
mock_memory_controller.read.return_value = 0x0
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(0xA2, registers, mock_memory_controller)
assert count == 2
mock_memory_controller.read.assert_called_with(1)
assert registers.x_index == 0x0
assert registers.pc == 2
assert registers.zero_flag
assert registers.negative_flag == False
def test_execute_sty_zeropage():
opcode = OpCode()
registers = Registers()
registers.y_index = 5
mock_memory_controller = Mock()
# we're mocking 0x84 0x30
mock_memory_controller.read.side_effect = [0x30]
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(0x84, registers, mock_memory_controller)
assert count == 3
assert mock_memory_controller.read.call_count == 1
assert mock_memory_controller.read.call_args_list[0] == unittest.mock.call(
1)
mock_memory_controller.write.assert_called_with(0x30, 5)
assert registers.pc == 2
def test_execute_lda_immediate_negative():
opcode = OpCode()
registers = Registers()
registers.zero_flag = True
registers.negative_flag = False
with patch.object(MemoryController, 'read') as mock_memory_controller:
mock_memory_controller.read.return_value = -1
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(0xA9, registers, mock_memory_controller)
assert count == 2
mock_memory_controller.read.assert_called_with(1)
assert registers.accumulator == -1
assert registers.pc == 2
assert registers.zero_flag == False
assert registers.negative_flag
def execute_adc_carry_clear( actual_opcode, expected_clocks):
opcode = OpCode()
registers = Registers()
registers.accumulator = 5
registers.zero_flag = True
registers.negative_flag = True
with patch.object(MemoryController, 'read') as mock_memory_controller:
mock_memory_controller.read.return_value = 0x22
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(actual_opcode, registers, mock_memory_controller)
assert count == expected_clocks
assert registers.accumulator == 0x27
assert registers.zero_flag == False
assert registers.negative_flag == False
assert registers.carry_flag == False
def test_execute_sbc_immediate_borrow_in_no_borrow_out_overflow_positive_result():
opcode = OpCode()
registers = Registers()
registers.accumulator = 0xd0 #start with negative acc this time
with patch.object(MemoryController, 'read') as mock_memory_controller:
# Mocking 0xE9 0x70 so subtracting 0xd0 - 0x70 (-48 - 112 = 96 (overflow))
mock_memory_controller.read.return_value = 0x70
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(0xE9, registers, mock_memory_controller)
assert count == 2
assert registers.accumulator == 0x5f
assert registers.zero_flag == False
assert registers.negative_flag == False
assert registers.carry_flag
assert registers.overflow_flag
def test_execute_sta_absolute_y():
opcode = OpCode()
registers = Registers()
registers.accumulator = 0x20
registers.y_index = 3
mock_memory_controller = Mock()
# we're mocking 0x99 0x2100 so write is to [0x2103]
mock_memory_controller.read.side_effect = [0, 0x21]
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(0x99, registers, mock_memory_controller)
assert count == 5
# these are checked more thoroughly in addressing_modes_tests
assert mock_memory_controller.read.call_count == 2
mock_memory_controller.write.assert_called_with(0x2103, 0x20)
assert registers.pc == 3
def test_execute_sbc_immediate_no_borrow_in_borrow_out_overflow_negative_result():
opcode = OpCode()
registers = Registers()
registers.accumulator = 0x50
registers.carry_flag = True
with patch.object(MemoryController, 'read') as mock_memory_controller:
# Mocking 0xE9 0xb0 so subtracting 0x50 - 0xb0 (80 - -80)
mock_memory_controller.read.return_value = 0xb0
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(0xE9, registers, mock_memory_controller)
assert count == 2
assert registers.accumulator == 0xa0
assert registers.zero_flag == False
assert registers.negative_flag
assert registers.carry_flag == False
assert registers.overflow_flag
def execute_sbc_borrow_in_borrow_out_no_overflow_positive_result( actual_opcode, expected_clocks, mock_memory_controller, **kwargs):
opcode = OpCode()
registers = Registers()
setattr(registers,'accumulator',0x50)
if kwargs:
for arg in kwargs:
setattr(registers, arg, kwargs[arg])
# Mocking 0x150 - 0xf0 (borrow 'in')
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(actual_opcode, registers, mock_memory_controller)
assert count == expected_clocks
assert registers.accumulator == 0x5f
assert registers.zero_flag == False
assert registers.negative_flag == False
assert registers.carry_flag == False
assert registers.overflow_flag == False
def test_execute_sty_absolute():
opcode = OpCode()
registers = Registers()
registers.y_index = 0x20
mock_memory_controller = Mock()
# we're mocking 0x8C 0x21 so store to [0x0024]
mock_memory_controller.read.side_effect = [0, 0x20]
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(0x8C, registers, mock_memory_controller)
assert count == 4
# these are checked more thoroughly in addressing_modes_tests
assert mock_memory_controller.read.call_count == 2
assert mock_memory_controller.read.call_args_list[0] == unittest.mock.call(
1)
mock_memory_controller.write.assert_called_with(0x2000, 0x20)
assert registers.pc == 3
def test_execute_adc_absolute():
opcode = OpCode()
registers = Registers()
registers.accumulator = 5
registers.zero_flag = True
registers.negative_flag = True
with patch.object(MemoryController, 'read') as mock_memory_controller:
# we're mocking 0xb5 0x21 0x22 and value at [0x2221] = 1
mock_memory_controller.read.side_effect = [0x21, 0x22, 1]
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(0x6D, registers, mock_memory_controller)
assert count == 4
assert registers.accumulator == 6
assert registers.zero_flag == False
assert registers.negative_flag == False
assert registers.carry_flag == False
def test_execute_inc_zeropage_zero():
opcode = OpCode()
registers = Registers()
mock_memory_controller = Mock()
mock_memory_controller.read.side_effect = [0x21, 0xff]
# we're mocking 0xE6 0x21 and [0x21] = 0xff
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(0xE6, registers, mock_memory_controller)
assert count == 5
assert mock_memory_controller.read.call_count == 2
assert mock_memory_controller.read.call_args_list[0] == unittest.mock.call(
1)
assert mock_memory_controller.read.call_args_list[1] == unittest.mock.call(
0x21)
mock_memory_controller.write.assert_called_with(0x21, 0)
assert registers.pc == 2
assert registers.zero_flag
assert registers.negative_flag == False
def test_execute_brk():
opcode = OpCode()
registers = Registers()
registers.sp = 0x200
mock_memory_controller = Mock()
mock_memory_controller.read.side_effect = [0x00, 0x21]
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(0x0, registers, mock_memory_controller)
assert count == 7
assert mock_memory_controller.read.call_count == 2
assert mock_memory_controller.write.call_count == 3
assert mock_memory_controller.write.call_args_list[0], unittest.mock.call(
0x200 == 1)
assert mock_memory_controller.write.call_args_list[1], unittest.mock.call(
0x1ff == 0)
assert mock_memory_controller.write.call_args_list[2], unittest.mock.call(
0x1fe == registers.status_register())
assert registers.pc == 0x2100
def test_execute_ldy_absolute():
opcode = OpCode()
registers = Registers()
registers.zero_flag = True
registers.negative_flag = False
with patch.object(MemoryController, 'read') as mock_memory_controller:
# we're mocking 0xa5 0x21 and value at [0x0021] = 1
mock_memory_controller.read.side_effect = [0x21, 0x22, 0xf0]
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(0xAC, registers, mock_memory_controller)
assert count == 4
# these are checked more thoroughly in addressing_modes_tests
assert mock_memory_controller.read.call_count == 3
assert registers.pc == 3
assert registers.x_index == 0
assert registers.zero_flag == False
assert registers.negative_flag
def test_execute_adc_absolute_y_page_boundary():
opcode = OpCode()
registers = Registers()
registers.accumulator = 5
registers.y_index = 3
registers.zero_flag = True
registers.negative_flag = True
with patch.object(MemoryController, 'read') as mock_memory_controller:
# we're mocking 0xBD 0x2100 and value at [0x2202] = 1
mock_memory_controller.read.side_effect = [0xff, 0x21, 1]
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(0x79, registers, mock_memory_controller)
assert count == 5
assert registers.accumulator == 6
assert registers.zero_flag == False
assert registers.negative_flag == False
assert registers.carry_flag == False
def test_execute_sta_zeropage_x_wrap():
opcode = OpCode()
registers = Registers()
registers.accumulator = 0x20
registers.x_index = 3
mock_memory_controller = Mock()
# we're mocking 0x95 0x21 so store to [0x0024]
mock_memory_controller.read.side_effect = [0xfe]
registers.pc += 1 #need to fake the cpu reading the opcode
count = opcode.execute(0x95, registers, mock_memory_controller)
assert count == 4
# these are checked more thoroughly in addressing_modes_tests
assert mock_memory_controller.read.call_count == 1
assert mock_memory_controller.read.call_args_list[0] == unittest.mock.call(
1)
mock_memory_controller.write.assert_called_with(0x01, 0x20)
assert registers.pc == 2