diff --git a/src/cpu.rs b/src/cpu.rs
index 5e6705e..9d24eef 100644
--- a/src/cpu.rs
+++ b/src/cpu.rs
@@ -515,102 +515,115 @@ impl CPU {
         );
     }
 
-    fn add_with_carry(&mut self, value: i8) {
-        if self.registers.status.contains(Status::PS_DECIMAL_MODE) {
-            // TODO akeeton: Implement binary-coded decimal.
-            debug!("binary-coded decimal not implemented for add_with_carry");
-        } else {
-            let a_before: i8 = self.registers.accumulator;
-            let c_before: i8 = if self.registers.status.contains(Status::PS_CARRY) {
-                1
-            } else {
-                0
-            };
-            let a_after: i8 = a_before.wrapping_add(c_before).wrapping_add(value);
+	fn add_with_carry(&mut self, value: i8) {
+		let a_before: i8 = self.registers.accumulator;
+		let c_before: i8 = if self.registers.status.contains(Status::PS_CARRY) {
+			1
+		} else {
+			0
+		};
+		let a_after: i8 = a_before.wrapping_add(c_before).wrapping_add(value);
 
-            debug_assert_eq!(
-                a_after as u8,
-                a_before.wrapping_add(c_before).wrapping_add(value) as u8
-            );
+		debug_assert_eq!(
+				a_after as u8,
+				a_before.wrapping_add(c_before).wrapping_add(value) as u8
+				);
 
-            let did_carry = (a_after as u8) < (a_before as u8);
+		let bcd1: i8 = if (a_after & 0x0f) as u8 > 0x09 {
+			0x06
+		} else {
+			0x00
+		};
 
-            let did_overflow = (a_before < 0 && value < 0 && a_after >= 0)
-                || (a_before > 0 && value > 0 && a_after <= 0);
+		let bcd2: i8 = if (a_after.wrapping_add(bcd1) as u8 & 0xf0) as u8 > 0x90 {
+			0x60
+		} else {
+			0x00
+		};
 
-            let mask = Status::PS_CARRY | Status::PS_OVERFLOW;
+		let result: i8 = if self.registers.status.contains(Status::PS_DECIMAL_MODE) {
+			a_after.wrapping_add(bcd1).wrapping_add(bcd2)
+		} else {
+			a_after
+		};
 
-            self.registers.status.set_with_mask(
-                mask,
-                Status::new(StatusArgs {
-                    carry: did_carry,
-                    overflow: did_overflow,
-                    ..StatusArgs::none()
-                }),
-            );
+		let did_carry = (result as u8) < (a_before as u8);
 
-            self.load_accumulator(a_after);
+		let did_overflow = (a_before < 0 && value < 0 && a_after >= 0)
+			|| (a_before > 0 && value > 0 && a_after <= 0);
 
-            debug!("accumulator: {}", self.registers.accumulator);
-        }
-    }
+		let mask = Status::PS_CARRY | Status::PS_OVERFLOW;
+
+		self.registers.status.set_with_mask( mask, Status::new(StatusArgs { carry: did_carry, overflow: did_overflow, ..StatusArgs::none() }),);
+
+		self.load_accumulator(result);
+
+		debug!("accumulator: {}", self.registers.accumulator);
+	}
 
     fn and(&mut self, value: i8) {
         let a_after = self.registers.accumulator & value;
         self.load_accumulator(a_after);
     }
 
-    // TODO: Implement binary-coded decimal
-    fn subtract_with_carry(&mut self, value: i8) {
-        if self.registers.status.contains(Status::PS_DECIMAL_MODE) {
-            debug!(
-                "binary-coded decimal not implemented for \
-                 subtract_with_carry"
-            );
-        } else {
-            // A - M - (1 - C)
+	fn subtract_with_carry(&mut self, value: i8) {
+		// A - M - (1 - C)
 
-            // nc -- 'not carry'
-            let nc: i8 = if self.registers.status.contains(Status::PS_CARRY) {
-                0
-            } else {
-                1
-            };
+		// nc -- 'not carry'
+		let nc: i8 = if self.registers.status.contains(Status::PS_CARRY) {
+			0
+		} else {
+			1
+		};
 
-            let a_before: i8 = self.registers.accumulator;
+		let a_before: i8 = self.registers.accumulator;
 
-            let a_after = a_before.wrapping_sub(value).wrapping_sub(nc);
+		let a_after = a_before.wrapping_sub(value).wrapping_sub(nc);
 
-            // The carry flag is set on unsigned overflow.
-            let did_carry = (a_after as u8) > (a_before as u8);
+		// The overflow flag is set on two's-complement overflow.
+		//
+		// range of A              is  -128 to 127
+		// range of - M - (1 - C)  is  -128 to 128
+		//                             -(127 + 1) to -(-128 + 0)
+		//
+		let over =
+			((nc == 0 && value < 0) || (nc == 1 && value < -1)) && a_before >= 0 && a_after < 0;
 
-            // The overflow flag is set on two's-complement overflow.
-            //
-            // range of A              is  -128 to 127
-            // range of - M - (1 - C)  is  -128 to 128
-            //                            -(127 + 1) to -(-128 + 0)
-            //
-            let over =
-                ((nc == 0 && value < 0) || (nc == 1 && value < -1)) && a_before >= 0 && a_after < 0;
+		let under = (a_before < 0) && (-value - nc < 0) && a_after >= 0;
 
-            let under = (a_before < 0) && (-value - nc < 0) && a_after >= 0;
+		let did_overflow = over || under;
 
-            let did_overflow = over || under;
+		let mask = Status::PS_CARRY | Status::PS_OVERFLOW;
 
-            let mask = Status::PS_CARRY | Status::PS_OVERFLOW;
+		let bcd1: i8 = if (a_before & 0x0f).wrapping_sub(nc) < (value & 0x0f) {
+			0x06
+		} else {
+			0x00
+		};
 
-            self.registers.status.set_with_mask(
-                mask,
-                Status::new(StatusArgs {
-                    carry: did_carry,
-                    overflow: did_overflow,
-                    ..StatusArgs::none()
-                }),
-            );
+		let bcd2: i8 = if (a_after.wrapping_sub(bcd1) as u8 & 0xf0) as u8 > 0x90 {
+			0x60
+		} else {
+			0x00
+		};
+		
+		let result: i8 = if self.registers.status.contains(Status::PS_DECIMAL_MODE) {
+			a_after.wrapping_sub(bcd1).wrapping_sub(bcd2)
+		} else {
+			a_after
+		};
 
-            self.load_accumulator(a_after);
-        }
-    }
+		// The carry flag is set on unsigned overflow.
+		let did_carry = (result as u8) > (a_before as u8);
+
+		self.registers.status.set_with_mask(
+				mask,
+				Status::new(StatusArgs { carry: did_carry, overflow: did_overflow, ..StatusArgs::none() }),
+				);
+
+
+		self.load_accumulator(result);
+	}
 
     fn decrement_memory(&mut self, addr: Address) {
         let value_new = self.memory.get_byte(addr).wrapping_sub(1);
@@ -766,6 +779,53 @@ mod tests {
     use super::*;
     use num::range_inclusive;
 
+	#[test]
+	fn decimal_add_test() {
+		let mut cpu = CPU::new();
+		cpu.registers.status.or(Status::PS_DECIMAL_MODE);
+		
+		cpu.add_with_carry(0x09);
+        assert_eq!(cpu.registers.accumulator, 0x09);
+        assert_eq!(cpu.registers.status.contains(Status::PS_CARRY), false);
+        assert_eq!(cpu.registers.status.contains(Status::PS_ZERO), false);
+        assert_eq!(cpu.registers.status.contains(Status::PS_NEGATIVE), false);
+        assert_eq!(cpu.registers.status.contains(Status::PS_OVERFLOW), false);
+
+		cpu.add_with_carry(0x43);
+        assert_eq!(cpu.registers.accumulator, 0x52);
+        assert_eq!(cpu.registers.status.contains(Status::PS_CARRY), false);
+        assert_eq!(cpu.registers.status.contains(Status::PS_ZERO), false);
+        assert_eq!(cpu.registers.status.contains(Status::PS_NEGATIVE), false);
+        assert_eq!(cpu.registers.status.contains(Status::PS_OVERFLOW), false);
+
+		cpu.add_with_carry(0x48);
+        assert_eq!(cpu.registers.accumulator, 0x00);
+        assert_eq!(cpu.registers.status.contains(Status::PS_CARRY), true);
+        assert_eq!(cpu.registers.status.contains(Status::PS_ZERO), true);
+        assert_eq!(cpu.registers.status.contains(Status::PS_NEGATIVE), false);
+        assert_eq!(cpu.registers.status.contains(Status::PS_OVERFLOW), true);
+	}
+
+	#[test]
+	fn decimal_subtract_test() {
+		let mut cpu = CPU::new();
+		cpu.registers.status.or(Status::PS_DECIMAL_MODE | Status::PS_CARRY);
+        cpu.registers.accumulator = 0;
+		
+		cpu.subtract_with_carry(0x48);
+        assert_eq!(cpu.registers.accumulator as u8, 0x52);
+        assert_eq!(cpu.registers.status.contains(Status::PS_CARRY), true);
+        assert_eq!(cpu.registers.status.contains(Status::PS_ZERO), false);
+        assert_eq!(cpu.registers.status.contains(Status::PS_NEGATIVE), false);
+        assert_eq!(cpu.registers.status.contains(Status::PS_OVERFLOW), false);
+
+		cpu.subtract_with_carry(0x43);
+        assert_eq!(cpu.registers.status.contains(Status::PS_CARRY), false);
+        assert_eq!(cpu.registers.status.contains(Status::PS_ZERO), false);
+        assert_eq!(cpu.registers.status.contains(Status::PS_NEGATIVE), false);
+        assert_eq!(cpu.registers.status.contains(Status::PS_OVERFLOW), false);
+	}
+
     #[test]
     fn add_with_carry_test() {
         let mut cpu = CPU::new();