From f1517d2126d00579fe93f89760155b7f9a60bf39 Mon Sep 17 00:00:00 2001
From: Anton Firszov <anton.firszov@sapagroup.com>
Date: Tue, 28 Mar 2017 00:59:14 +0200
Subject: [PATCH 1/2] fixing #146

---
 src/ImageSharp/Colors/Color.BulkOperations.cs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/ImageSharp/Colors/Color.BulkOperations.cs b/src/ImageSharp/Colors/Color.BulkOperations.cs
index 039fafced6..7d3b12ea0b 100644
--- a/src/ImageSharp/Colors/Color.BulkOperations.cs
+++ b/src/ImageSharp/Colors/Color.BulkOperations.cs
@@ -42,6 +42,12 @@ namespace ImageSharp
                 BufferSpan<Vector4> destVectors,
                 int count)
             {
+                if (!Vector.IsHardwareAccelerated)
+                {
+                    throw new InvalidOperationException(
+                        "Color.BulkOperations.ToVector4SimdAligned() should not be called when Vector.IsHardwareAccelerated == false!");
+                }
+
                 int vecSize = Vector<uint>.Count;
 
                 DebugGuard.IsTrue(
@@ -92,7 +98,7 @@ namespace ImageSharp
             /// <inheritdoc />
             internal override void ToVector4(BufferSpan<Color> sourceColors, BufferSpan<Vector4> destVectors, int count)
             {
-                if (count < 256)
+                if (count < 256 || !Vector.IsHardwareAccelerated)
                 {
                     // Doesn't worth to bother with SIMD:
                     base.ToVector4(sourceColors, destVectors, count);

From 4231a109953009ea162df2e5e9c9440b61b58573 Mon Sep 17 00:00:00 2001
From: Anton Firszov <anton.firszov@sapagroup.com>
Date: Tue, 28 Mar 2017 02:26:18 +0200
Subject: [PATCH 2/2] PackFromVector4ReferenceVsPointer benchmark

---
 .../Bulk/PackFromVector4ReferenceVsPointer.cs | 74 +++++++++++++++++++
 1 file changed, 74 insertions(+)
 create mode 100644 tests/ImageSharp.Benchmarks/Color/Bulk/PackFromVector4ReferenceVsPointer.cs

diff --git a/tests/ImageSharp.Benchmarks/Color/Bulk/PackFromVector4ReferenceVsPointer.cs b/tests/ImageSharp.Benchmarks/Color/Bulk/PackFromVector4ReferenceVsPointer.cs
new file mode 100644
index 0000000000..e912ea29f6
--- /dev/null
+++ b/tests/ImageSharp.Benchmarks/Color/Bulk/PackFromVector4ReferenceVsPointer.cs
@@ -0,0 +1,74 @@
+namespace ImageSharp.Benchmarks
+{
+    using System.Numerics;
+    using System.Runtime.CompilerServices;
+
+    using BenchmarkDotNet.Attributes;
+
+    using ImageSharp;
+    
+    /// <summary>
+    /// Compares two implementation candidates for general BulkPixelOperations.ToVector4():
+    /// - One iterating with pointers
+    /// - One iterating with ref locals
+    /// </summary>
+    public unsafe class PackFromVector4ReferenceVsPointer
+    {
+        private PinnedBuffer<ImageSharp.Color> destination;
+
+        private PinnedBuffer<Vector4> source;
+
+        [Params(16, 128, 1024)]
+        public int Count { get; set; }
+
+        [Setup]
+        public void Setup()
+        {
+            this.destination = new PinnedBuffer<ImageSharp.Color>(this.Count);
+            this.source = new PinnedBuffer<Vector4>(this.Count * 4);
+        }
+
+        [Cleanup]
+        public void Cleanup()
+        {
+            this.source.Dispose();
+            this.destination.Dispose();
+        }
+
+        [Benchmark(Baseline = true)]
+        public void PackUsingPointers()
+        {
+            Vector4* sp = (Vector4*)this.source.Pointer;
+            byte* dp = (byte*)this.destination.Pointer;
+            int count = this.Count;
+            int size = sizeof(ImageSharp.Color);
+
+            for (int i = 0; i < count; i++)
+            {
+                Vector4 v = Unsafe.Read<Vector4>(sp);
+                ImageSharp.Color c = default(ImageSharp.Color);
+                c.PackFromVector4(v);
+                Unsafe.Write(dp, c);
+
+                sp++;
+                dp += size;
+            }
+        }
+
+        [Benchmark]
+        public void PackUsingReferences()
+        {
+            ref Vector4 sp = ref this.source.Array[0];
+            ref ImageSharp.Color dp = ref this.destination.Array[0];
+            int count = this.Count;
+
+            for (int i = 0; i < count; i++)
+            {
+                dp.PackFromVector4(sp);
+
+                sp = Unsafe.Add(ref sp, 1);
+                dp = Unsafe.Add(ref dp, 1);
+            }
+        }
+    }
+}
\ No newline at end of file