diff --git a/src/ImageSharp/PixelFormats/PixelBlenders/PorterDuffFunctions.cs b/src/ImageSharp/PixelFormats/PixelBlenders/PorterDuffFunctions.cs
index fa497c872..af111849a 100644
--- a/src/ImageSharp/PixelFormats/PixelBlenders/PorterDuffFunctions.cs
+++ b/src/ImageSharp/PixelFormats/PixelBlenders/PorterDuffFunctions.cs
@@ -293,8 +293,8 @@ internal static partial class PorterDuffFunctions
         // calculate weights
         Vector256<float> sW = Avx.Permute(source, ShuffleAlphaControl);
         Vector256<float> dW = Avx.Permute(destination, ShuffleAlphaControl);
-        Vector256<float> blendW = Avx.Multiply(sW, dW);
 
+        Vector256<float> blendW = Avx.Multiply(sW, dW);
         Vector256<float> dstW = Avx.Subtract(dW, blendW);
         Vector256<float> srcW = Avx.Subtract(sW, blendW);
 
@@ -303,8 +303,8 @@ internal static partial class PorterDuffFunctions
 
         // calculate final color
         Vector256<float> color = Avx.Multiply(destination, dstW);
-        color = SimdUtils.HwIntrinsics.MultiplyAdd(source, srcW, color);
-        color = SimdUtils.HwIntrinsics.MultiplyAdd(blend, blendW, color);
+        color = SimdUtils.HwIntrinsics.MultiplyAdd(color, source, srcW);
+        color = SimdUtils.HwIntrinsics.MultiplyAdd(color, blend, blendW);
 
         // unpremultiply
         color = Avx.Divide(color, Avx.Max(alpha, Vector256.Create(Constants.Epsilon)));
@@ -349,15 +349,15 @@ internal static partial class PorterDuffFunctions
     public static Vector256<float> Atop(Vector256<float> destination, Vector256<float> source, Vector256<float> blend)
     {
         // calculate final alpha
-        Vector256<float> alpha = Avx.Shuffle(destination, destination, ShuffleAlphaControl);
+        Vector256<float> alpha = Avx.Permute(destination, ShuffleAlphaControl);
 
         // calculate weights
-        Vector256<float> sW = Avx.Shuffle(source, source, ShuffleAlphaControl);
+        Vector256<float> sW = Avx.Permute(source, ShuffleAlphaControl);
         Vector256<float> blendW = Avx.Multiply(sW, alpha);
         Vector256<float> dstW = Avx.Subtract(alpha, blendW);
 
         // calculate final color
-        Vector256<float> color = SimdUtils.HwIntrinsics.MultiplyAdd(destination, dstW, Avx.Multiply(blend, blendW));
+        Vector256<float> color = SimdUtils.HwIntrinsics.MultiplyAdd(Avx.Multiply(blend, blendW), destination, dstW);
 
         // unpremultiply
         color = Avx.Divide(color, Avx.Max(alpha, Vector256.Create(Constants.Epsilon)));
@@ -482,8 +482,8 @@ internal static partial class PorterDuffFunctions
         Vector256<float> dstW = Avx.Subtract(vOne, sW);
 
         // calculate alpha
-        Vector256<float> alpha = SimdUtils.HwIntrinsics.MultiplyAdd(sW, srcW, Avx.Multiply(dW, dstW));
-        Vector256<float> color = SimdUtils.HwIntrinsics.MultiplyAdd(Avx.Multiply(sW, source), srcW, Avx.Multiply(Avx.Multiply(dW, destination), dstW));
+        Vector256<float> alpha = SimdUtils.HwIntrinsics.MultiplyAdd(Avx.Multiply(dW, dstW), sW, srcW);
+        Vector256<float> color = SimdUtils.HwIntrinsics.MultiplyAdd(Avx.Multiply(Avx.Multiply(dW, destination), dstW), Avx.Multiply(sW, source), srcW);
 
         // unpremultiply
         color = Avx.Divide(color, Avx.Max(alpha, Vector256.Create(Constants.Epsilon)));
diff --git a/tests/ImageSharp.Tests/PixelFormats/PixelBlenders/PorterDuffFunctionsTests.cs b/tests/ImageSharp.Tests/PixelFormats/PixelBlenders/PorterDuffFunctionsTests.cs
index 45dece8ec..02b4b0ea5 100644
--- a/tests/ImageSharp.Tests/PixelFormats/PixelBlenders/PorterDuffFunctionsTests.cs
+++ b/tests/ImageSharp.Tests/PixelFormats/PixelBlenders/PorterDuffFunctionsTests.cs
@@ -2,6 +2,7 @@
 // Licensed under the Six Labors Split License.
 
 using System.Numerics;
+using System.Runtime.Intrinsics;
 using SixLabors.ImageSharp.PixelFormats.PixelBlenders;
 using SixLabors.ImageSharp.Tests.TestUtilities;
 
@@ -9,7 +10,7 @@ namespace SixLabors.ImageSharp.Tests.PixelFormats.PixelBlenders;
 
 public class PorterDuffFunctionsTests
 {
-    public static TheoryData<TestVector4, TestVector4, float, TestVector4> NormalBlendFunctionData = new TheoryData<TestVector4, TestVector4, float, TestVector4>
+    public static TheoryData<TestVector4, TestVector4, float, TestVector4> NormalBlendFunctionData { get; } = new()
     {
         { new TestVector4(1, 1, 1, 1), new TestVector4(1, 1, 1, 1), 1, new TestVector4(1, 1, 1, 1) },
         { new TestVector4(1, 1, 1, 1), new TestVector4(0, 0, 0, .8f), .5f, new TestVector4(0.6f, 0.6f, 0.6f, 1) }
@@ -23,7 +24,19 @@ public class PorterDuffFunctionsTests
         Assert.Equal(expected, actual);
     }
 
-    public static TheoryData<TestVector4, TestVector4, float, TestVector4> MultiplyFunctionData = new TheoryData<TestVector4, TestVector4, float, TestVector4>
+    [Theory]
+    [MemberData(nameof(NormalBlendFunctionData))]
+    public void NormalBlendFunction256(TestVector4 back, TestVector4 source, float amount, TestVector4 expected)
+    {
+        Vector256<float> back256 = Vector256.Create(back.X, back.Y, back.Z, back.W, back.X, back.Y, back.Z, back.W);
+        Vector256<float> source256 = Vector256.Create(source.X, source.Y, source.Z, source.W, source.X, source.Y, source.Z, source.W);
+
+        Vector256<float> expected256 = Vector256.Create(expected.X, expected.Y, expected.Z, expected.W, expected.X, expected.Y, expected.Z, expected.W);
+        Vector256<float> actual = PorterDuffFunctions.NormalSrcOver(back256, source256, Vector256.Create(amount));
+        Assert.Equal(expected256, actual);
+    }
+
+    public static TheoryData<TestVector4, TestVector4, float, TestVector4> MultiplyFunctionData { get; } = new()
     {
         { new TestVector4(1, 1, 1, 1), new TestVector4(1, 1, 1, 1), 1, new TestVector4(1, 1, 1, 1) },
         { new TestVector4(1, 1, 1, 1), new TestVector4(0, 0, 0, .8f), .5f, new TestVector4(0.6f, 0.6f, 0.6f, 1) },
@@ -38,7 +51,7 @@ public class PorterDuffFunctionsTests
         VectorAssert.Equal(expected, actual, 5);
     }
 
-    public static TheoryData<TestVector4, TestVector4, float, TestVector4> AddFunctionData = new TheoryData<TestVector4, TestVector4, float, TestVector4>
+    public static TheoryData<TestVector4, TestVector4, float, TestVector4> AddFunctionData { get; } = new()
     {
         { new TestVector4(1, 1, 1, 1), new TestVector4(1, 1, 1, 1), 1, new TestVector4(1, 1, 1, 1) },
         { new TestVector4(1, 1, 1, 1), new TestVector4(0, 0, 0, .8f), .5f, new TestVector4(.6f, .6f, .6f, 1f) },
@@ -53,7 +66,7 @@ public class PorterDuffFunctionsTests
         VectorAssert.Equal(expected, actual, 5);
     }
 
-    public static TheoryData<TestVector4, TestVector4, float, TestVector4> SubtractFunctionData = new TheoryData<TestVector4, TestVector4, float, TestVector4>
+    public static TheoryData<TestVector4, TestVector4, float, TestVector4> SubtractFunctionData { get; } = new()
     {
         { new TestVector4(1, 1, 1, 1), new TestVector4(1, 1, 1, 1), 1, new TestVector4(0, 0, 0, 1) },
         { new TestVector4(1, 1, 1, 1), new TestVector4(0, 0, 0, .8f), .5f, new TestVector4(1, 1, 1, 1f) },
@@ -68,7 +81,7 @@ public class PorterDuffFunctionsTests
         VectorAssert.Equal(expected, actual, 5);
     }
 
-    public static TheoryData<TestVector4, TestVector4, float, TestVector4> ScreenFunctionData = new TheoryData<TestVector4, TestVector4, float, TestVector4>
+    public static TheoryData<TestVector4, TestVector4, float, TestVector4> ScreenFunctionData { get; } = new()
     {
         { new TestVector4(1, 1, 1, 1), new TestVector4(1, 1, 1, 1), 1, new TestVector4(1, 1, 1, 1) },
         { new TestVector4(1, 1, 1, 1), new TestVector4(0, 0, 0, .8f), .5f, new TestVector4(1, 1, 1, 1f) },
@@ -83,7 +96,7 @@ public class PorterDuffFunctionsTests
         VectorAssert.Equal(expected, actual, 5);
     }
 
-    public static TheoryData<TestVector4, TestVector4, float, TestVector4> DarkenFunctionData = new TheoryData<TestVector4, TestVector4, float, TestVector4>
+    public static TheoryData<TestVector4, TestVector4, float, TestVector4> DarkenFunctionData { get; } = new()
     {
         { new TestVector4(1, 1, 1, 1), new TestVector4(1, 1, 1, 1), 1, new TestVector4(1, 1, 1, 1) },
         { new TestVector4(1, 1, 1, 1), new TestVector4(0, 0, 0, .8f), .5f, new TestVector4(.6f, .6f, .6f, 1f) },
@@ -98,7 +111,7 @@ public class PorterDuffFunctionsTests
         VectorAssert.Equal(expected, actual, 5);
     }
 
-    public static TheoryData<TestVector4, TestVector4, float, TestVector4> LightenFunctionData = new TheoryData<TestVector4, TestVector4, float, TestVector4>
+    public static TheoryData<TestVector4, TestVector4, float, TestVector4> LightenFunctionData { get; } = new()
     {
         { new TestVector4(1, 1, 1, 1), new TestVector4(1, 1, 1, 1), 1, new TestVector4(1, 1, 1, 1) },
         { new TestVector4(1, 1, 1, 1), new TestVector4(0, 0, 0, .8f), .5f, new TestVector4(1, 1, 1, 1f) },
@@ -113,7 +126,7 @@ public class PorterDuffFunctionsTests
         VectorAssert.Equal(expected, actual, 5);
     }
 
-    public static TheoryData<TestVector4, TestVector4, float, TestVector4> OverlayFunctionData = new TheoryData<TestVector4, TestVector4, float, TestVector4>
+    public static TheoryData<TestVector4, TestVector4, float, TestVector4> OverlayFunctionData { get; } = new()
     {
         { new TestVector4(1, 1, 1, 1), new TestVector4(1, 1, 1, 1), 1, new TestVector4(1, 1, 1, 1) },
         { new TestVector4(1, 1, 1, 1), new TestVector4(0, 0, 0, .8f), .5f, new TestVector4(1, 1, 1, 1f) },
@@ -128,7 +141,7 @@ public class PorterDuffFunctionsTests
         VectorAssert.Equal(expected, actual, 5);
     }
 
-    public static TheoryData<TestVector4, TestVector4, float, TestVector4> HardLightFunctionData = new TheoryData<TestVector4, TestVector4, float, TestVector4>
+    public static TheoryData<TestVector4, TestVector4, float, TestVector4> HardLightFunctionData { get; } = new()
     {
         { new TestVector4(1, 1, 1, 1), new TestVector4(1, 1, 1, 1), 1, new TestVector4(1, 1, 1, 1) },
         { new TestVector4(1, 1, 1, 1), new TestVector4(0, 0, 0, .8f), .5f, new TestVector4(0.6f, 0.6f, 0.6f, 1f) },