diff --git a/src/spider/runtime/instr/Instr_000-01F.cpp b/src/spider/runtime/instr/Instr_000-01F.cpp
index 89f661d..088b8d9 100644
--- a/src/spider/runtime/instr/Instr_000-01F.cpp
+++ b/src/spider/runtime/instr/Instr_000-01F.cpp
@@ -71,13 +71,13 @@ namespace spider {
         // TODO: Implement COM
         fetchOperDst();
         switch(_size){
-            case 0b00:
+            case 0b00: //byte
                 _dst->_u8 = ~_dst->_u8;
-            case 0b01:
+            case 0b01: //short
                 _dst->_u16 = ~_dst->_u16;
-            case 0b10:
+            case 0b10: //int
                 _dst->_u32 = ~_dst->_u32;
-            case 0b11:
+            case 0b11: //long
                 _dst->_u64 = ~_dst->_u64;
         }
         (this->*_post)();
@@ -87,13 +87,13 @@ namespace spider {
         // TODO: Implement NEG
         fetchOperDst();
         switch(_size){
-            case 0b00:
+            case 0b00: //byte
                 _dst->_u8 = 1 + ~_dst->_u8;
-            case 0b01:
+            case 0b01: //short
                 _dst->_u16 = 1+ ~_dst->_u16;
-            case 0b10:
+            case 0b10: //int
                 _dst->_u32 = 1 + ~_dst->_u32;
-            case 0b11:
+            case 0b11: //long
                 _dst->_u64 = 1 + ~_dst->_u64;
         }
         (this->*_post)();
@@ -101,6 +101,19 @@ namespace spider {
 
     void CPU::EXS() {
         // TODO: Implement EXS
+        fetchOperDst();
+        switch(_size){
+            case 0b00: //byte
+                _dst->_u32 = _dst->_u8 & 1;
+            case 0b01: //short
+                _dst->_u32 = _dst->_u16 & 1;
+            case 0b10: //int
+                _dst->_u32 = _dst->_u32 & 1;
+            case 0b11: //long
+                _dst->_u32 = _dst->_u64 & 1;
+        }
+        _dst->_u32 = _dst->_u8;
+        (this->*_post)();
     }
 
     void CPU::INC() {