def test_sub_op_pos_neg_neg_overflow(self):
# Subtract -2 from POS_MAX
self.vmac.flags |= ZERO
value = self.vmac._sub(0x7FFF, utils.to_hex(-2) )
self.assertEqual(value, 0x8001)
self.assertTrue(self.vmac.flags & OVERFLOW)
self.assertTrue(self.vmac.flags & CARRY)
self.assertFalse(self.vmac.flags & ZERO)
self.assertTrue(self.vmac.flags & NEGATIVE)
def test_sub_op_pos_pos_neg(self):
# Subtract 49 from 7
self.vmac.flags |= OVERFLOW | ZERO
value = self.vmac._sub(7, 49)
self.assertEqual(value, utils.to_hex(-42) )
self.assertFalse(self.vmac.flags & OVERFLOW)
self.assertTrue(self.vmac.flags & CARRY)
self.assertFalse(self.vmac.flags & ZERO)
self.assertTrue(self.vmac.flags & NEGATIVE)
def test_sub_op_neg_pos_pos_underflow(self):
# Subtract POS_MAX from -2
self.vmac.flags |= CARRY | ZERO | NEGATIVE
value = self.vmac._sub(utils.to_hex(-2), 0x7FFF)
self.assertEqual(value, 0x7FFF)
self.assertTrue(self.vmac.flags & OVERFLOW)
self.assertFalse(self.vmac.flags & CARRY)
self.assertFalse(self.vmac.flags & ZERO)
self.assertFalse(self.vmac.flags & NEGATIVE)
def test_neg_max_to_hex(self):
self.assertEqual(utils.to_hex(-32768), 0x8000)
def test_neg_one_to_hex(self):
self.assertEqual(utils.to_hex(-1), 0xFFFF)
def test_max_to_hex(self):
self.assertEqual(utils.to_hex(32767), 0x7FFF)
def test_1_to_hex(self):
self.assertEqual(utils.to_hex(1), 0x1)
def test_0_to_hex(self):
self.assertEqual(utils.to_hex(0), 0x0)
