def test_asl(self, accumulator_state, expected):
test_cpu = cpu.Cpu()
test_cpu.accumulator = accumulator_state
asl(test_cpu, cpu.AddressingMode.accumulator)
assert test_cpu.accumulator == expected
def test_carry(accumulator_state, immediate, expected):
"""Test that carry bit is set when add operation overflows."""
test_cpu = cpu.Cpu()
test_cpu.accumulator = accumulator_state
add.add_with_carry(test_cpu, cpu.AddressingMode.immediate, immediate)
assert test_cpu.status.carry == expected
def test_clear(self, status_flag, init_state):
"""Test that status flags are always set to false when clear instruction is called."""
test_cpu = cpu.Cpu()
setattr(test_cpu.status, status_flag.name, init_state)
clear._clear_flag(test_cpu, status_flag)
assert not getattr(test_cpu.status, status_flag.name)
def test_negative_flag(self, accumulator_state, expected):
"""Test that negative bit is set if the result is negative."""
test_cpu = cpu.Cpu()
test_cpu.accumulator = accumulator_state
asl(test_cpu, cpu.AddressingMode.accumulator)
assert test_cpu.status.negative == expected
def test_adding(accumulator_state, immediate, expected):
"""Test basic adding functionality between accumulator and immediate value."""
test_cpu = cpu.Cpu()
test_cpu.accumulator = accumulator_state
add.add_with_carry(test_cpu, cpu.AddressingMode.immediate, immediate)
assert test_cpu.accumulator == expected
assert not test_cpu.status.carry
def test_zero_flag(self, accumulator_state, expected):
"""Test that result is zero."""
test_cpu = cpu.Cpu()
test_cpu.accumulator = accumulator_state
asl(test_cpu, cpu.AddressingMode.accumulator)
assert test_cpu.status.zero == expected
def test_negative_flag(accumulator_state, immediate, expected):
"""Test that negative bit is set if the result is negative."""
test_cpu = cpu.Cpu()
test_cpu.accumulator = accumulator_state
add.add_with_carry(test_cpu, cpu.AddressingMode.immediate, immediate)
assert test_cpu.status.negative == expected
def test_absolute():
"""Test that absolute addressing gets the value from memory, then performs same addition as immediate."""
test_cpu = cpu.Cpu()
test_cpu.memory = bytearray(b'\x00\x00\x05\x00')
with mock.patch.object(add, '_add_with_carry_immediate', wraps=add._add_with_carry_immediate) as mock_add:
add.add_with_carry(test_cpu, cpu.AddressingMode.absolute, 2)
mock_add.assert_called_with(test_cpu, 5), 'Memory is not accessed in the right place.'
def test_overflow(accumulator_state, immediate, expected):
"""Test that overflow bit is set when add operation overflows.
This is only meaningful if the inputs were intended to be signed values."""
test_cpu = cpu.Cpu()
test_cpu.accumulator = accumulator_state
add.add_with_carry(test_cpu, cpu.AddressingMode.immediate, immediate)
assert test_cpu.status.overflow == expected
def test_negative(self, accumulator_state, memory_value, expected):
"""Test that negative is set to 7th bit of memory value."""
test_cpu = cpu.Cpu()
test_cpu.accumulator = accumulator_state
test_cpu.memory = bytearray(10)
test_cpu.memory[2] = memory_value
bit.bit(test_cpu, 2)
assert test_cpu.status.negative == expected
def test_overflow(self, accumulator_state, memory_value, expected):
"""Test that overflow is set to 6th bit of memory value."""
test_cpu = cpu.Cpu()
test_cpu.accumulator = accumulator_state
test_cpu.memory = bytearray(10)
test_cpu.memory[2] = memory_value
bit.bit(test_cpu, 2)
assert test_cpu.status.overflow == expected
def test_zero_page():
"""Test that zero page addressing is alias for absolute addressing."""
test_cpu = cpu.Cpu()
test_cpu.memory = bytearray(b'\x00\x00\x05\x00')
function = add._add_with_carry_absolute
with mock.patch.object(add, function.__name__, wraps=function) as mock_add:
add.add_with_carry(test_cpu, cpu.AddressingMode.zero_page, 2)
assert mock_add.called, 'zero_page addressing mode should be identical to absolute mode'
def test_zero(self, accumulator_state, memory_value, expected):
"""Test that zero flag is only set if bitmasking is zero."""
test_cpu = cpu.Cpu()
test_cpu.accumulator = accumulator_state
test_cpu.memory = bytearray(10)
test_cpu.memory[2] = memory_value
bit.bit(test_cpu, 2)
assert test_cpu.status.zero == expected
def test_zero_flag(accumulator_state, immediate):
"""Test that result is zero."""
assert (
accumulator_state + immediate
) % cpu.MAX_UNSIGNED_VALUE == 0, 'Test code assertion, test inputs must only for result == 0'
test_cpu = cpu.Cpu()
test_cpu.accumulator = accumulator_state
add.add_with_carry(test_cpu, cpu.AddressingMode.immediate, immediate)
assert test_cpu.status.zero
def test_unaffected_flag(accumulator_state, immediate, flag_state):
"""Test that other flags are unchanged."""
test_cpu = cpu.Cpu()
test_cpu.accumulator = accumulator_state
test_cpu.status.interrupt_disable = flag_state
test_cpu.status.decimal = flag_state
test_cpu.status.break_ = flag_state
add.add_with_carry(test_cpu, cpu.AddressingMode.immediate, immediate)
assert test_cpu.status.interrupt_disable == flag_state
assert test_cpu.status.decimal == flag_state
assert test_cpu.status.break_ == flag_state
def test_unaffected_flag(self, accumulator_state, flag_state):
"""Test that other flags are unchanged."""
test_cpu = cpu.Cpu()
test_cpu.accumulator = accumulator_state
test_cpu.status.interrupt_disable = flag_state
test_cpu.status.decimal = flag_state
test_cpu.status.break_ = flag_state
test_cpu.status.overflow = flag_state
asl(test_cpu, cpu.AddressingMode.accumulator)
assert test_cpu.status.interrupt_disable == flag_state
assert test_cpu.status.decimal == flag_state
assert test_cpu.status.break_ == flag_state
assert test_cpu.status.overflow == flag_state
def test_unaffected_flag(self, status_flag, init_state, flag_state):
"""Test that other flags are unchanged."""
test_cpu = cpu.Cpu()
setattr(test_cpu.status, status_flag.name, init_state)
other_status = set(cpu.StatusFlag) - {status_flag}
# Set state of target status flags
for i in other_status:
setattr(test_cpu.status, i.name, flag_state)
clear._clear_flag(test_cpu, status_flag)
# Assert state of target status flags unchanged
for i in other_status:
assert getattr(test_cpu.status, i.name) == flag_state
def test_unaffected_flag(self, accumulator_state, memory_value,
flag_state):
"""Test that other flags are unchanged."""
test_cpu = cpu.Cpu()
test_cpu.accumulator = accumulator_state
test_cpu.memory = bytearray(10)
test_cpu.memory[2] = memory_value
test_cpu.status.carry = flag_state
test_cpu.status.interrupt_disable = flag_state
test_cpu.status.decimal = flag_state
test_cpu.status.break_ = flag_state
bit.bit(test_cpu, 2)
assert test_cpu.status.carry == flag_state
assert test_cpu.status.interrupt_disable == flag_state
assert test_cpu.status.decimal == flag_state
assert test_cpu.status.break_ == flag_state
def test_unaffected_flag(self, test_cpu, flag_state):
"""Test that other flags are unchanged."""
test_cpu = cpu.Cpu()
test_cpu.program_counter = 100
test_cpu.status.carry = flag_state
test_cpu.status.zero = flag_state
test_cpu.status.interrupt_disable = flag_state
test_cpu.status.decimal = flag_state
test_cpu.status.break_ = flag_state
test_cpu.status.overflow = flag_state
test_cpu.status.negative = flag_state
branch._branch(test_cpu, flag_state, 10)
assert test_cpu.status.carry == flag_state
assert test_cpu.status.zero == flag_state
assert test_cpu.status.interrupt_disable == flag_state
assert test_cpu.status.decimal == flag_state
assert test_cpu.status.break_ == flag_state
assert test_cpu.status.overflow == flag_state
assert test_cpu.status.negative == flag_state
def test_cpu():
test_cpu = cpu.Cpu()
test_cpu.program_counter = 100
test_cpu.status.carry = False
yield test_cpu
def test_cpu():
test_cpu = cpu.Cpu()
test_cpu.memory = bytearray(b'\x00\x00\x05\x00')
yield test_cpu
def test_unsupported_flags(self, status_flag):
"""Test that these statuses do not have clear instruction support."""
test_cpu = cpu.Cpu()
with pytest.raises(NotImplementedError):
clear._clear_flag(test_cpu, status_flag)
def test_clear_carry(self, mock_clear):
test_cpu = cpu.Cpu()
clear.clear_carry(test_cpu)
mock_clear.assert_called_with(test_cpu, cpu.StatusFlag.carry)
def test_clear_decimal(self, mock_clear):
test_cpu = cpu.Cpu()
clear.clear_decimal(test_cpu)
mock_clear.assert_called_with(test_cpu, cpu.StatusFlag.decimal)
def test_clear_interrupt(self, mock_clear):
test_cpu = cpu.Cpu()
clear.clear_interrupt(test_cpu)
mock_clear.assert_called_with(test_cpu,
cpu.StatusFlag.interrupt_disable)
def test_clear_overflow(self, mock_clear):
test_cpu = cpu.Cpu()
clear.clear_overflow(test_cpu)
mock_clear.assert_called_with(test_cpu, cpu.StatusFlag.overflow)
def test_not_placeholder(self):
cpu_instance = cpu.Cpu()
cpu_instance.decode_instruction('NOT_PLACEHOLDER') # type: ignore
