How to optimize fixed point numbers?

I am trying to implement fixed point math in unity. I am in the process of benchmarking simple functions and comparing them to unity's built in integer functions. While doing this, I found that the fixed point functions were about twice as slow as the integer equivalent even if i didn't do any operations in them (ie. return 1;)

Here is the class:

 using System;
 using UnityEngine;

 [Serializable]
 public struct fp {

     //the underlying int value of the fixed point number
     [SerializeField]
     public int rawValue;
     public int RawValue { get { return rawValue; } }

     public const int MAX_VALUE = int.MaxValue;
     public const int MIN_VALUE = int.MinValue;
     public const int TOTAL_BITS = 32;
     public const int DECIMAL_BITS = 16;

     public static implicit operator fp (int value) {
         return new fp(value);
     }

     public fp (int _rawValue) {
         rawValue = _rawValue;
     }

     public static int Sign (fp value) {

         return 
             value.rawValue > 0 ? 1 :
             value.rawValue < 0 ? -1 :
             0;

     }

     public static int FastSign (fp value) {

         return 1;

     }

     public static fp Abs (fp value) {

         var mask = value.rawValue >> 31;
         return new fp ((value.rawValue + mask) ^ mask);

     }

 }

Any thoughts on how I can speed these up?