ft(interpreter): impl ret with immediate

src/interpreter/interpreter.rs

@@ -612,6 +612,13 @@ impl Interpreter {
                     self.set_ip(return_addr as usize);
                     continue;
                 }
+                Mnemonic::RET_Iw(w) => {
+                    let return_addr = self.computer.pop_stack()?;
+                    self.set_ip(return_addr as usize);
+                    // release no longer needed values from stack
+                    self.computer.regs.sp += w;
+                    continue;
+                }
 
                 /*
                  * Load ES/DS Register