Implemented register to register instructions

src/build/Function.go

@@ -142,13 +142,18 @@ func (f *Function) CompileVariableDefinition(expr *expression.Expression) error
 		return err
 	}
 
-	// All expressions are returned to the memory pool.
-	// To avoid losing variable values, we will detach it from the expression.
-	expr.RemoveChild(value)
+	reg, exists := f.CPU.FindFree()
+
+	if !exists {
+		panic("no free registers")
+	}
+
+	f.ExpressionToRegister(value, reg)
+	f.CPU.Use(reg)
 
 	f.Variables[name] = &Variable{
-		Name:  name,
-		Value: value,
+		Name:     name,
+		Register: reg,
 	}
 
 	return nil
@@ -197,7 +202,8 @@ func (f *Function) TokenToRegister(t token.Token, register cpu.Register) error {
 			return errors.New(&errors.UnknownIdentifier{Name: name}, f.File, t.Position)
 		}
 
-		return f.ExpressionToRegister(variable.Value, register)
+		f.Assembler.MoveRegisterRegister(register, variable.Register)
+		return nil
 
 	case token.Number:
 		value := t.Text()