diff --git a/src/codegen/codegen.rs b/src/codegen/codegen.rs
index c530655..d8cd6cc 100644
--- a/src/codegen/codegen.rs
+++ b/src/codegen/codegen.rs
@@ -44,14 +44,7 @@ impl<'a> CodeGen<'a> {
             text_section: formatdoc!(
                 "
                 section .text
-                    global _start
-
-                _start:
-                    call main
-
-                    mov rax, 60
-                    mov rdi, 0
-                    syscall
+                    global main
 
                 main:
                 "
@@ -110,11 +103,23 @@ impl<'a> CodeGen<'a> {
 
                     self.mov(name, right);
 
-                    return 69;
+                    69
                 } else {
                     panic!("Cant assign to non ident");
                 }
             }
+            BinOp::Add => {
+                let left = self.expr(expr.left.as_ref());
+                let right = self.expr(expr.right.as_ref());
+
+                self.add(left, right)
+            }
+            BinOp::Sub => {
+                let left = self.expr(expr.left.as_ref());
+                let right = self.expr(expr.right.as_ref());
+
+                self.sub(left, right)
+            }
             _ => panic!("lasjdf"),
         }
     }
@@ -162,6 +167,38 @@ impl<'a> CodeGen<'a> {
         r
     }
 
+    fn add(&mut self, r1: usize, r2: usize) -> usize {
+        writedoc!(
+            self.text_section,
+            "
+            \tadd {}, {}
+            ",
+            &self.registers[r1].name,
+            &self.registers[r2].name,
+        )
+        .unwrap();
+
+        self.free(r2);
+
+        r1
+    }
+
+    fn sub(&mut self, r1: usize, r2: usize) -> usize {
+        writedoc!(
+            self.text_section,
+            "
+            \tsub {}, {}
+            ",
+            &self.registers[r1].name,
+            &self.registers[r2].name,
+        )
+        .unwrap();
+
+        self.free(r2);
+
+        r1
+    }
+
     pub fn compile(&mut self, program: Vec<Stmt>, path: &str) {
         let mut file = File::create(path).expect(&format!("Failed to open a file {}", path));
 
diff --git a/src/main.rs b/src/main.rs
index 11912aa..7566528 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -12,7 +12,7 @@ fn main() {
         "
         u8 bar;
 
-        bar = 69;
+        bar = 5 + 10 - 12;
         "
         .to_string(),
     );