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Remove page wrap bug from JMP indirect on 65C02

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This commit is contained in:
Mike Naberezny 2014-01-22 22:56:02 -08:00
parent 7cf76952a4
commit ec311c879e
3 changed files with 32 additions and 11 deletions
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5
py65/devices/mpu65c02.py
View File

@ -279,6 +279,11 @@ class MPU(mpu6502.MPU):
def inst_0x3a(self):
self.opDECR(None)
@instruction(name="JMP", mode="ind", cycles=6)
def inst_0x6c(self):
ta = self.WordAt(self.pc)
self.pc = self.WordAt(ta)
@instruction(name="JMP", mode="iax", cycles=6)
def inst_0x7c(self):
self.pc = self.WordAt(self.IndirectAbsXAddr())

27
py65/tests/devices/test_mpu6502.py
View File

@ -2648,16 +2648,18 @@ class Common6502Tests:
self.assertEqual(0x80, mpu.y)
self.assertEqual(mpu.NEGATIVE, mpu.p & mpu.NEGATIVE)
# JMP
# JMP Absolute
def test_jmp_jumps_to_absolute_address(self):
def test_jmp_abs_jumps_to_absolute_address(self):
mpu = self._make_mpu()
# $0000 JMP $ABCD
self._write(mpu.memory, 0x0000, (0x4C, 0xCD, 0xAB))
mpu.step()
self.assertEqual(0xABCD, mpu.pc)
def test_jmp_jumps_to_indirect_address(self):
# JMP Indirect
def test_jmp_ind_jumps_to_indirect_address(self):
mpu = self._make_mpu()
# $0000 JMP ($ABCD)
self._write(mpu.memory, 0x0000, (0x6C, 0x00, 0x02))
@ -5669,6 +5671,17 @@ class MPUTests(unittest.TestCase, Common6502Tests):
self.assertEqual(mpu.BREAK, mpu.p & mpu.BREAK)
self.assertEqual(0, mpu.p & mpu.DECIMAL)
# JMP Indirect
def test_jmp_jumps_to_address_with_page_wrap_bug(self):
mpu = self._make_mpu()
mpu.memory[0x00ff] = 0
# $0000 JMP ($00)
self._write(mpu.memory, 0, (0x6c, 0xff, 0x00))
mpu.step()
self.assertEqual(0x6c00, mpu.pc)
self.assertEqual(5, mpu.processorCycles)
# Test page wrapping
def test_zeropage_indexed_ind_wrap(self):
@ -5709,14 +5722,6 @@ class MPUTests(unittest.TestCase, Common6502Tests):
mpu.step()
self.assertEqual(0x31, mpu.a)
def test_indirect_wrap(self):
mpu = self._make_mpu()
mpu.memory[0x00ff] = 0
# $0000 JMP ($00)
self._write(mpu.memory, 0, (0x6c, 0xff, 0x00))
mpu.step()
self.assertEqual(0x6c00, mpu.pc)
def _get_target_class(self):
return py65.devices.mpu6502.MPU

11
py65/tests/devices/test_mpu65c02.py
View File

@ -475,6 +475,17 @@ class MPUTests(unittest.TestCase, Common6502Tests):
self.assertEqual(mpu.NEGATIVE, mpu.p & mpu.NEGATIVE)
self.assertEqual(0, mpu.p & mpu.ZERO)
# JMP Indirect
def test_jmp_ind_does_not_have_page_wrap_bug(self):
mpu = self._make_mpu()
self._write(mpu.memory, 0x10FF, (0xCD, 0xAB))
# $0000 JMP ($10FF)
self._write(mpu.memory, 0, (0x6c, 0xFF, 0x10))
mpu.step()
self.assertEqual(0xABCD, mpu.pc)
self.assertEqual(6, mpu.processorCycles)
# JMP Indirect Absolute X-Indexed
def test_jmp_iax_jumps_to_address(self):