class TestArithmeticOperations(unittest.TestCase):
def setUp(self):
self.memory = Memory(use_bus=False)
self.cpu = CPU(self.memory)
def test_ADC_without_BCD(self):
## test cases from http://www.6502.org/tutorials/vflag.html
# 1 + 1 = 2 (C = 0; V = 0)
self.cpu.carry_flag = 0
self.cpu.accumulator = 0x01
self.memory.write_byte(None, 0x1000, 0x01)
self.cpu.ADC(0x1000)
self.assertEqual(self.cpu.accumulator, 0x02)
self.assertEqual(self.cpu.carry_flag, 0)
self.assertEqual(self.cpu.overflow_flag, 0)
# 1 + -1 = 0 (C = 1; V = 0)
self.cpu.carry_flag = 0
self.cpu.accumulator = 0x01
self.memory.write_byte(None, 0x1000, 0xFF)
self.cpu.ADC(0x1000)
self.assertEqual(self.cpu.accumulator, 0x00)
self.assertEqual(self.cpu.carry_flag, 1)
self.assertEqual(self.cpu.overflow_flag, 0)
# 127 + 1 = 128 (C = 0; V = 1)
self.cpu.carry_flag = 0
self.cpu.accumulator = 0x7F
self.memory.write_byte(None, 0x1000, 0x01)
self.cpu.ADC(0x1000)
self.assertEqual(self.cpu.accumulator, 0x80) # @@@
self.assertEqual(self.cpu.carry_flag, 0)
self.assertEqual(self.cpu.overflow_flag, 1)
# -128 + -1 = -129 (C = 1; V = 1)
self.cpu.carry_flag = 0
self.cpu.accumulator = 0x80
self.memory.write_byte(None, 0x1000, 0xFF)
self.cpu.ADC(0x1000)
self.assertEqual(self.cpu.accumulator, 0x7F) # @@@
self.assertEqual(self.cpu.carry_flag, 1)
self.assertEqual(self.cpu.overflow_flag, 1)
# 63 + 64 + 1 = 128 (C = 0; V = 1)
self.cpu.carry_flag = 1
self.cpu.accumulator = 0x3F
self.memory.write_byte(None, 0x1000, 0x40)
self.cpu.ADC(0x1000)
self.assertEqual(self.cpu.accumulator, 0x80)
self.assertEqual(self.cpu.carry_flag, 0)
self.assertEqual(self.cpu.overflow_flag, 1)
def test_SBC_without_BCD(self):
self.cpu.accumulator = 0x02
self.memory.write_byte(None, 0x1000, 0x01)
self.cpu.SBC(0x1000)
self.assertEqual(self.cpu.accumulator, 0x00)
self.assertEqual(self.cpu.carry_flag, 1)
self.assertEqual(self.cpu.overflow_flag, 0)
self.cpu.accumulator = 0x01
self.memory.write_byte(None, 0x1000, 0x02)
self.cpu.SBC(0x1000)
self.assertEqual(self.cpu.accumulator, 0xFF)
self.assertEqual(self.cpu.carry_flag, 0)
self.assertEqual(self.cpu.overflow_flag, 0) # @@@
## test cases from http://www.6502.org/tutorials/vflag.html
# 0 - 1 = -1 (V = 0)
self.cpu.carry_flag = 1
self.cpu.accumulator = 0x00
self.memory.write_byte(None, 0x1000, 0x01)
self.cpu.SBC(0x1000)
self.assertEqual(self.cpu.accumulator, 0xFF)
self.assertEqual(self.cpu.carry_flag, 0)
self.assertEqual(self.cpu.overflow_flag, 0) # @@@
# -128 - 1 = -129 (V = 1)
self.cpu.carry_flag = 1
self.cpu.accumulator = 0x80
self.memory.write_byte(None, 0x1000, 0x01)
self.cpu.SBC(0x1000)
self.assertEqual(self.cpu.accumulator, 0x7F)
self.assertEqual(self.cpu.carry_flag, 1)
self.assertEqual(self.cpu.overflow_flag, 1)
# 127 - -1 = 128 (V = 1)
self.cpu.carry_flag = 1
self.cpu.accumulator = 0x7F
self.memory.write_byte(None, 0x1000, 0xFF)
self.cpu.SBC(0x1000)
self.assertEqual(self.cpu.accumulator, 0x80)
self.assertEqual(self.cpu.carry_flag, 0)
self.assertEqual(self.cpu.overflow_flag, 1)
# -64 -64 -1 = -129 (V = 1)
self.cpu.carry_flag = 0
self.cpu.accumulator = 0xC0
self.memory.write_byte(None, 0x1000, 0x40)
self.cpu.SBC(0x1000)
self.assertEqual(self.cpu.accumulator, 0x7F)
self.assertEqual(self.cpu.carry_flag, 1)
self.assertEqual(self.cpu.overflow_flag, 1) # @@@
## @@@ BCD versions still to do
def test_CMP(self):
self.cpu.accumulator = 0x0A
self.memory.write_byte(None, 0x1000, 0x09)
self.cpu.CMP(0x1000)
self.assertEqual(self.cpu.sign_flag, 0)
self.assertEqual(self.cpu.zero_flag, 0)
self.assertEqual(self.cpu.carry_flag, 1)
self.cpu.accumulator = 0x0A
self.memory.write_byte(None, 0x1000, 0x0B)
self.cpu.CMP(0x1000)
self.assertEqual(self.cpu.sign_flag, 1)
self.assertEqual(self.cpu.zero_flag, 0)
self.assertEqual(self.cpu.carry_flag, 0)
self.cpu.accumulator = 0x0A
self.memory.write_byte(None, 0x1000, 0x0A)
self.cpu.CMP(0x1000)
self.assertEqual(self.cpu.sign_flag, 0)
self.assertEqual(self.cpu.zero_flag, 1)
self.assertEqual(self.cpu.carry_flag, 1)
self.cpu.accumulator = 0xA0
self.memory.write_byte(None, 0x1000, 0x0A)
self.cpu.CMP(0x1000)
self.assertEqual(self.cpu.sign_flag, 1)
self.assertEqual(self.cpu.zero_flag, 0)
self.assertEqual(self.cpu.carry_flag, 1)
self.cpu.accumulator = 0x0A
self.memory.write_byte(None, 0x1000, 0xA0)
self.cpu.CMP(0x1000)
self.assertEqual(self.cpu.sign_flag, 0) # @@@
self.assertEqual(self.cpu.zero_flag, 0)
self.assertEqual(self.cpu.carry_flag, 0)
def test_CPX(self):
self.cpu.x_index = 0x0A
self.memory.write_byte(None, 0x1000, 0x09)
self.cpu.CPX(0x1000)
self.assertEqual(self.cpu.sign_flag, 0)
self.assertEqual(self.cpu.zero_flag, 0)
self.assertEqual(self.cpu.carry_flag, 1)
self.cpu.x_index = 0x0A
self.memory.write_byte(None, 0x1000, 0x0B)
self.cpu.CPX(0x1000)
self.assertEqual(self.cpu.sign_flag, 1)
self.assertEqual(self.cpu.zero_flag, 0)
self.assertEqual(self.cpu.carry_flag, 0)
self.cpu.x_index = 0x0A
self.memory.write_byte(None, 0x1000, 0x0A)
self.cpu.CPX(0x1000)
self.assertEqual(self.cpu.sign_flag, 0)
self.assertEqual(self.cpu.zero_flag, 1)
self.assertEqual(self.cpu.carry_flag, 1)
self.cpu.x_index = 0xA0
self.memory.write_byte(None, 0x1000, 0x0A)
self.cpu.CPX(0x1000)
self.assertEqual(self.cpu.sign_flag, 1)
self.assertEqual(self.cpu.zero_flag, 0)
self.assertEqual(self.cpu.carry_flag, 1)
self.cpu.x_index = 0x0A
self.memory.write_byte(None, 0x1000, 0xA0)
self.cpu.CPX(0x1000)
self.assertEqual(self.cpu.sign_flag, 0) # @@@
self.assertEqual(self.cpu.zero_flag, 0)
self.assertEqual(self.cpu.carry_flag, 0)
def test_CPY(self):
self.cpu.y_index = 0x0A
self.memory.write_byte(None, 0x1000, 0x09)
self.cpu.CPY(0x1000)
self.assertEqual(self.cpu.sign_flag, 0)
self.assertEqual(self.cpu.zero_flag, 0)
self.assertEqual(self.cpu.carry_flag, 1)
self.cpu.y_index = 0x0A
self.memory.write_byte(None, 0x1000, 0x0B)
self.cpu.CPY(0x1000)
self.assertEqual(self.cpu.sign_flag, 1)
self.assertEqual(self.cpu.zero_flag, 0)
self.assertEqual(self.cpu.carry_flag, 0)
self.cpu.y_index = 0x0A
self.memory.write_byte(None, 0x1000, 0x0A)
self.cpu.CPY(0x1000)
self.assertEqual(self.cpu.sign_flag, 0)
self.assertEqual(self.cpu.zero_flag, 1)
self.assertEqual(self.cpu.carry_flag, 1)
self.cpu.y_index = 0xA0
self.memory.write_byte(None, 0x1000, 0x0A)
self.cpu.CPY(0x1000)
self.assertEqual(self.cpu.sign_flag, 1)
self.assertEqual(self.cpu.zero_flag, 0)
self.assertEqual(self.cpu.carry_flag, 1)
self.cpu.y_index = 0x0A
self.memory.write_byte(None, 0x1000, 0xA0)
self.cpu.CPY(0x1000)
self.assertEqual(self.cpu.sign_flag, 0) # @@@
self.assertEqual(self.cpu.zero_flag, 0)
self.assertEqual(self.cpu.carry_flag, 0)
