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add 3 (failing) BCD tests and comment a weak spot in opSBC

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This commit is contained in:
Ed Spittles 2010-11-29 17:40:13 +00:00
parent f7c7d97a96
commit b234ac4c32
2 changed files with 43 additions and 1 deletions
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2
src/py65/devices/mpu6502.py
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@ -375,7 +375,7 @@ class MPU:
else:
self.p |= self.NEGATIVE
data +=100
self.a = convert_to_bcd(data)
self.a = convert_to_bcd(data) # throws exception if result is over 99 decimal
else:
if self.p & self.CARRY:
borrow = 0

42
src/py65/tests/devices/test_mpu6502.py
View File

@ -333,6 +333,20 @@ class Common6502Tests:
self.assertEquals(mpu.OVERFLOW, mpu.p & mpu.OVERFLOW)
self.assertEquals(0, mpu.p & mpu.ZERO)
def test_adc_bcd_on_immediate_79_plus_00_carry_set(self):
mpu = self._make_mpu()
mpu.p |= mpu.DECIMAL
mpu.p |= mpu.CARRY
mpu.a = 0x79
self._write(mpu.memory, 0x0000, (0x69, 0x00)) #=> $0000 ADC #$00
mpu.step()
self.assertEquals(0x0002, mpu.pc)
self.assertEquals(0x80, mpu.a)
self.assertEquals(mpu.NEGATIVE, mpu.p & mpu.NEGATIVE)
self.assertEquals(mpu.OVERFLOW, mpu.p & mpu.OVERFLOW)
self.assertEquals(0, mpu.p & mpu.ZERO)
self.assertEquals(0, mpu.p & mpu.CARRY)
# ADC Absolute, X-Indexed
def test_adc_bcd_off_abs_x_carry_clear_in_accumulator_zeroes(self):
@ -4084,6 +4098,34 @@ class Common6502Tests:
self.assertEquals(0, mpu.p & mpu.ZERO)
self.assertEquals(mpu.CARRY, mpu.CARRY)
def test_sbc_bcd_on_immediate_0a_minus_00_carry_set(self):
mpu = self._make_mpu()
mpu.p |= mpu.DECIMAL
mpu.p |= mpu.CARRY
mpu.a = 0x0a
self._write(mpu.memory, 0x0000, (0xe9, 0x00)) #=> $0000 SBC #$00
mpu.step()
self.assertEquals(0x0002, mpu.pc)
self.assertEquals(0x0a, mpu.a)
self.assertEquals(0, mpu.p & mpu.NEGATIVE)
self.assertEquals(0, mpu.p & mpu.OVERFLOW)
self.assertEquals(0, mpu.p & mpu.ZERO)
self.assertEquals(mpu.CARRY, mpu.p & mpu.CARRY)
def test_sbc_bcd_on_immediate_9a_minus_00_carry_set(self):
mpu = self._make_mpu()
mpu.p |= mpu.DECIMAL
mpu.p |= mpu.CARRY
mpu.a = 0x9a
self._write(mpu.memory, 0x0000, (0xe9, 0x00)) #=> $0000 SBC #$00
mpu.step()
self.assertEquals(0x0002, mpu.pc)
self.assertEquals(0x9a, mpu.a)
self.assertEquals(mpu.NEGATIVE, mpu.p & mpu.NEGATIVE)
self.assertEquals(0, mpu.p & mpu.OVERFLOW)
self.assertEquals(0, mpu.p & mpu.ZERO)
self.assertEquals(mpu.CARRY, mpu.p & mpu.CARRY)
# SBC Absolute, X-Indexed
def test_sbc_abs_x_all_zeros_and_no_borrow_is_zero(self):