New subtract immediate instruction

src/instruction.rs

@@ -40,6 +40,7 @@ pub enum OpCode {
     GetObj,
     SetObj,
     Addi,
+    Subi,
     GetIter,
     GetIterk,
     GetIteri,

src/vm.rs

@@ -1186,6 +1186,39 @@ impl VM {
                     }
                     pc += 1;
                 }
+                OpCode::Subi => {
+                    let val_b = self
+                        .activation_records
+                        .get_mut(sp + inst.b as usize)
+                        .unwrap()
+                        .clone();
+                    if let Record::Val(Value::Number(n)) = val_b {
+                        self.activation_records[sp + inst.a as usize] = Record::Val(Value::Number(NumberValue {
+                            n: n.n - inst.c as f64
+                        }));
+                    } else {
+                        match val_b
+                            .as_val()
+                            .sub(&mut Value::Number(NumberValue { n: inst.c as f64 }))
+                        {
+                            Ok(v) => {
+                                self.activation_records[sp + inst.a as usize] = Record::Val(v);
+                            }
+                            Err(e) => {
+                                throw_exception!(
+                                    self,
+                                    this,
+                                    original_instructions,
+                                    original_instructions_data,
+                                    pc,
+                                    sp,
+                                    e
+                                );
+                            }
+                        }
+                    }
+                    pc += 1;
+                }
                 OpCode::GetIter => {
                     let val_b = self
                         .activation_records