diff --git a/src/cpus/m68k/execute.rs b/src/cpus/m68k/execute.rs
index 93aca9d..0d0def9 100644
--- a/src/cpus/m68k/execute.rs
+++ b/src/cpus/m68k/execute.rs
@@ -184,8 +184,17 @@ impl M68k {
                 let (result, _) = overflowing_add_sized(existing, value, Size::Long);
                 *self.get_a_reg_mut(dest) = result;
             },
-            //Instruction::ADDX(Target) => {
-            //},
+            Instruction::ADDX(src, dest, size) => {
+                let value = self.get_target_value(src, size)?;
+                let existing = self.get_target_value(dest, size)?;
+                let extend = self.get_flag(Flags::Extend) as u32;
+                let (result1, carry1) = overflowing_add_sized(existing, value, size);
+                let (result2, carry2) = overflowing_add_sized(result1, extend, size);
+                let overflow = get_add_overflow(existing, value, result2, size);
+                self.set_compare_flags(result2, size, carry1 || carry2, overflow);
+                self.set_flag(Flags::Extend, carry1 || carry2);
+                self.set_target_value(dest, result2, size)?;
+            },
             Instruction::AND(src, dest, size) => {
                 let value = self.get_target_value(src, size)?;
                 let existing = self.get_target_value(dest, size)?;
@@ -689,8 +698,17 @@ impl M68k {
                 let (result, _) = overflowing_sub_sized(existing, value, Size::Long);
                 *self.get_a_reg_mut(dest) = result;
             },
-            //Instruction::SUBX(Target) => {
-            //},
+            Instruction::SUBX(src, dest, size) => {
+                let value = self.get_target_value(src, size)?;
+                let existing = self.get_target_value(dest, size)?;
+                let extend = self.get_flag(Flags::Extend) as u32;
+                let (result1, carry1) = overflowing_sub_sized(existing, value, size);
+                let (result2, carry2) = overflowing_sub_sized(result1, extend, size);
+                let overflow = get_sub_overflow(existing, value, result2, size);
+                self.set_compare_flags(result2, size, carry1 || carry2, overflow);
+                self.set_flag(Flags::Extend, carry1 || carry2);
+                self.set_target_value(dest, result2, size)?;
+            },
             Instruction::SWAP(reg) => {
                 let value = self.state.d_reg[reg as usize];
                 self.state.d_reg[reg as usize] = ((value & 0x0000FFFF) << 16) | ((value & 0xFFFF0000) >> 16);
diff --git a/src/cpus/m68k/tests.rs b/src/cpus/m68k/tests.rs
index 5dafb25..8420c17 100644
--- a/src/cpus/m68k/tests.rs
+++ b/src/cpus/m68k/tests.rs
@@ -518,6 +518,30 @@ mod execute_tests {
             init: TestState { pc: 0x00000000, ssp: 0x00000000, usp: 0x00000000, d0: 0x0000F800, d1: 0x00000000, a0: 0x00000000, a1: 0x00000000, sr: 0x27FF, mem: 0x00000000 },
             fini: TestState { pc: 0x00000002, ssp: 0x00000000, usp: 0x00000000, d0: 0x0000F800, d1: 0x00000000, a0: 0xFFFFF800, a1: 0x00000000, sr: 0x27FF, mem: 0x00000000 },
         },
+        TestCase {
+            name: "addx",
+            ins: Instruction::ADDX(Target::DirectDReg(1), Target::DirectDReg(0), Size::Byte),
+            data: &[ 0xD101 ],
+            cputype: M68kType::MC68010,
+            init: TestState { pc: 0x00000000, ssp: 0x00000000, usp: 0x00000000, d0: 0x0000007F, d1: 0x0000007F, a0: 0x00000000, a1: 0x00000000, sr: 0x2700, mem: 0x00000000 },
+            fini: TestState { pc: 0x00000002, ssp: 0x00000000, usp: 0x00000000, d0: 0x000000FE, d1: 0x0000007F, a0: 0x00000000, a1: 0x00000000, sr: 0x270A, mem: 0x00000000 },
+        },
+        TestCase {
+            name: "addx with extend",
+            ins: Instruction::ADDX(Target::DirectDReg(1), Target::DirectDReg(0), Size::Byte),
+            data: &[ 0xD101 ],
+            cputype: M68kType::MC68010,
+            init: TestState { pc: 0x00000000, ssp: 0x00000000, usp: 0x00000000, d0: 0x0000007F, d1: 0x0000007F, a0: 0x00000000, a1: 0x00000000, sr: 0x2710, mem: 0x00000000 },
+            fini: TestState { pc: 0x00000002, ssp: 0x00000000, usp: 0x00000000, d0: 0x000000FF, d1: 0x0000007F, a0: 0x00000000, a1: 0x00000000, sr: 0x270A, mem: 0x00000000 },
+        },
+        TestCase {
+            name: "addx with extend and carry",
+            ins: Instruction::ADDX(Target::DirectDReg(1), Target::DirectDReg(0), Size::Byte),
+            data: &[ 0xD101 ],
+            cputype: M68kType::MC68010,
+            init: TestState { pc: 0x00000000, ssp: 0x00000000, usp: 0x00000000, d0: 0x00000080, d1: 0x0000007F, a0: 0x00000000, a1: 0x00000000, sr: 0x2710, mem: 0x00000000 },
+            fini: TestState { pc: 0x00000002, ssp: 0x00000000, usp: 0x00000000, d0: 0x00000000, d1: 0x0000007F, a0: 0x00000000, a1: 0x00000000, sr: 0x2715, mem: 0x00000000 },
+        },
         TestCase {
             name: "andi with sr",
             ins: Instruction::ANDtoSR(0xF8FF),
@@ -933,6 +957,31 @@ mod execute_tests {
             init: TestState { pc: 0x00000000, ssp: 0x00000000, usp: 0x00000000, d0: 0x00000001, d1: 0x00000000, a0: 0x00000000, a1: 0x00000000, sr: 0x2700, mem: 0x00000000 },
             fini: TestState { pc: 0x00000002, ssp: 0x00000000, usp: 0x00000000, d0: 0x00000080, d1: 0x00000000, a0: 0x00000000, a1: 0x00000000, sr: 0x2708, mem: 0x00000000 },
         },
+
+        TestCase {
+            name: "subx",
+            ins: Instruction::SUBX(Target::DirectDReg(1), Target::DirectDReg(0), Size::Byte),
+            data: &[ 0x9101 ],
+            cputype: M68kType::MC68010,
+            init: TestState { pc: 0x00000000, ssp: 0x00000000, usp: 0x00000000, d0: 0x000000FF, d1: 0x0000007F, a0: 0x00000000, a1: 0x00000000, sr: 0x2700, mem: 0x00000000 },
+            fini: TestState { pc: 0x00000002, ssp: 0x00000000, usp: 0x00000000, d0: 0x00000080, d1: 0x0000007F, a0: 0x00000000, a1: 0x00000000, sr: 0x2708, mem: 0x00000000 },
+        },
+        TestCase {
+            name: "subx with extend",
+            ins: Instruction::SUBX(Target::DirectDReg(1), Target::DirectDReg(0), Size::Byte),
+            data: &[ 0x9101 ],
+            cputype: M68kType::MC68010,
+            init: TestState { pc: 0x00000000, ssp: 0x00000000, usp: 0x00000000, d0: 0x000000FF, d1: 0x0000007F, a0: 0x00000000, a1: 0x00000000, sr: 0x2710, mem: 0x00000000 },
+            fini: TestState { pc: 0x00000002, ssp: 0x00000000, usp: 0x00000000, d0: 0x0000007F, d1: 0x0000007F, a0: 0x00000000, a1: 0x00000000, sr: 0x2702, mem: 0x00000000 },
+        },
+        TestCase {
+            name: "subx with extend and carry",
+            ins: Instruction::SUBX(Target::DirectDReg(1), Target::DirectDReg(0), Size::Byte),
+            data: &[ 0x9101 ],
+            cputype: M68kType::MC68010,
+            init: TestState { pc: 0x00000000, ssp: 0x00000000, usp: 0x00000000, d0: 0x00000000, d1: 0x0000007F, a0: 0x00000000, a1: 0x00000000, sr: 0x2710, mem: 0x00000000 },
+            fini: TestState { pc: 0x00000002, ssp: 0x00000000, usp: 0x00000000, d0: 0x00000080, d1: 0x0000007F, a0: 0x00000000, a1: 0x00000000, sr: 0x2719, mem: 0x00000000 },
+        },
     ];