diff --git a/src/main.rs b/src/main.rs
index 06d9dee..ae49ac2 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -80,10 +80,45 @@ fn parse(contents: String, opcodes: HashMap<&'static str, (i64, i32)>) -> Vec<i6
     return code
 }
 
-fn exec(instructions: Vec<i64>) {
-    for elem in instructions {
-        println!("{}", elem);
+fn exec(instructions: Vec<i64>) -> i64 {
+    let mut stack: Vec<i64> = Vec::new();
+    let ilen = instructions.len();
+    let mut ip = 0;
+    while ip < ilen {
+        ip += 1; /* TMP */
+        match instructions[ip] {
+            /* ENT */ 0 => (),
+            /* ADD */ 1 => (),
+            /* SUB */ 2 => (),
+            /* MUL */ 3 => (),
+            /* DIV */ 4 => (),
+            /* MOD */ 5 => (),
+            /* LT  */ 6 => (),
+            /* EQ  */ 7 => (),
+            /* GT  */ 8 => (),
+            /* BR  */ 9 => (),
+            /* BRT */ 10 => (),
+            /* BRF */ 11 => (),
+            /* CST */ 12 => (),
+            /* LD  */ 13 => (),
+            /* GLD */ 14 => (),
+            /* ST  */ 15 => (),
+            /* GST */ 16 => (),
+            /* PRN */ 17 => (),
+            /* POP */ 18 => (),
+            /* HLT */ 19 => break,
+            /* LEQ */ 20 => (),
+            /* GEQ */ 21 => (),
+            /* CAL */ 22 => (),
+            /* RET */ 23 => (),
+            /* IPR */ 24 => (),
+            /* FET */ 25 => (),
+            /* INC */ 26 => (),
+            /* DEC */ 27 => (),
+            /* IMP */ x => panic!("Unknown instruction {}!", x)
+        }
     }
+    return *stack.first().unwrap_or(&0);
 }
 
 fn main() {
@@ -109,5 +144,5 @@ fn main() {
 
     let parsed = parse(contents, opcodes);
 
-    let execd = exec(parsed);
+    println!("{}", exec(parsed));
 }