diff --git a/src/py65/tests/devices/test_mpu6502.py b/src/py65/tests/devices/test_mpu6502.py
index 997a116..f067445 100644
--- a/src/py65/tests/devices/test_mpu6502.py
+++ b/src/py65/tests/devices/test_mpu6502.py
@@ -361,6 +361,24 @@ class Common6502Tests:
     self.assertEqual(0, mpu.p & mpu.ZERO)       
     self.assertEqual(0, mpu.p & mpu.CARRY)
 
+  def test_adc_bcd_on_immediate_9c_plus_9d(self):
+    mpu = self._make_mpu()
+    mpu.p |= mpu.DECIMAL
+    mpu.p &= ~(mpu.CARRY)
+    mpu.a = 0x9c
+    self._write(mpu.memory, 0x0000, (0x69, 0x9d)) #=> $0000 ADC #$9d
+    self._write(mpu.memory, 0x0002, (0x69, 0x9d)) #=> $0000 ADC #$9d
+    mpu.step()
+    self.assertEqual(0x9f, mpu.a)
+    self.assertEqual(mpu.CARRY, mpu.p & mpu.CARRY)
+    mpu.step()
+    self.assertEqual(0x0004, mpu.pc)
+    self.assertEqual(0x93, mpu.a)
+    self.assertEqual(0, mpu.p & mpu.NEGATIVE)
+    self.assertEqual(mpu.OVERFLOW, mpu.p & mpu.OVERFLOW)
+    self.assertEqual(0, mpu.p & mpu.ZERO)
+    self.assertEqual(mpu.CARRY, mpu.p & mpu.CARRY)
+
   # ADC Absolute, X-Indexed
   
   def test_adc_bcd_off_abs_x_carry_clear_in_accumulator_zeroes(self):
@@ -4156,6 +4174,19 @@ class Common6502Tests:
     self.assertEqual(0, mpu.p & mpu.ZERO)       
     self.assertEqual(0, mpu.p & mpu.CARRY)
 
+  def test_sbc_bcd_on_immediate_20_minus_0a_carry_unset(self):
+    mpu = self._make_mpu()
+    mpu.p |= mpu.DECIMAL
+    mpu.a = 0x20
+    self._write(mpu.memory, 0x0000, (0xe9, 0x0a)) #=> $0000 SBC #$00
+    mpu.step()
+    self.assertEqual(0x0002, mpu.pc)
+    self.assertEqual(0x1f, mpu.a)
+    self.assertEqual(0, mpu.p & mpu.NEGATIVE)
+    self.assertEqual(0, mpu.p & mpu.OVERFLOW)
+    self.assertEqual(0, mpu.p & mpu.ZERO)
+    self.assertEqual(mpu.CARRY, mpu.p & mpu.CARRY)
+
   # SBC Absolute, X-Indexed
   
   def test_sbc_abs_x_all_zeros_and_no_borrow_is_zero(self):