From 9ae92244f1146c2a0eafaa39199b2242ea641960 Mon Sep 17 00:00:00 2001
From: James Jackson-South <james_south@hotmail.com>
Date: Sat, 21 Jan 2017 07:57:13 +1100
Subject: [PATCH] Faster FastAbs

---
 src/ImageSharp/Common/Helpers/ImageMaths.cs | 3 ++-
 tests/ImageSharp.Benchmarks/General/Abs.cs  | 8 ++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/ImageSharp/Common/Helpers/ImageMaths.cs b/src/ImageSharp/Common/Helpers/ImageMaths.cs
index 147a5914b..fc94c689f 100644
--- a/src/ImageSharp/Common/Helpers/ImageMaths.cs
+++ b/src/ImageSharp/Common/Helpers/ImageMaths.cs
@@ -25,7 +25,8 @@ namespace ImageSharp
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static int FastAbs(int x)
         {
-            return (x ^ (x >> 31)) - (x >> 31);
+            int y = x >> 31;
+            return (x ^ y) - y;
         }
 
         /// <summary>
diff --git a/tests/ImageSharp.Benchmarks/General/Abs.cs b/tests/ImageSharp.Benchmarks/General/Abs.cs
index b0f033b81..b5b449467 100644
--- a/tests/ImageSharp.Benchmarks/General/Abs.cs
+++ b/tests/ImageSharp.Benchmarks/General/Abs.cs
@@ -29,5 +29,13 @@
             int x = this.X;
             return (x ^ (x >> 31)) - (x >> 31);
         }
+
+        [Benchmark(Description = "Bitwise Abs With Variable")]
+        public int AbsBitwiseVer()
+        {
+            int x = this.X;
+            int y = x >> 31;
+            return (x ^ y) - y;
+        }
     }
 }