From 597bc0c10158201fbfa1126a99865bdbf6267d05 Mon Sep 17 00:00:00 2001
From: James Jackson-South <james_south@hotmail.com>
Date: Fri, 2 May 2025 23:21:27 +1000
Subject: [PATCH] Update MultiplyAdd

---
 src/ImageSharp/Common/Helpers/Vector256Utilities.cs |  2 +-
 src/ImageSharp/Common/Helpers/Vector512Utilities.cs | 10 +++++++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/ImageSharp/Common/Helpers/Vector256Utilities.cs b/src/ImageSharp/Common/Helpers/Vector256Utilities.cs
index a7366f6da..9928b529e 100644
--- a/src/ImageSharp/Common/Helpers/Vector256Utilities.cs
+++ b/src/ImageSharp/Common/Helpers/Vector256Utilities.cs
@@ -146,7 +146,7 @@ internal static class Vector256Utilities
     {
         if (Fma.IsSupported)
         {
-            return Fma.MultiplyAdd(vm1, vm0, va);
+            return Fma.MultiplyAdd(vm0, vm1, va);
         }
 
         if (Avx.IsSupported)
diff --git a/src/ImageSharp/Common/Helpers/Vector512Utilities.cs b/src/ImageSharp/Common/Helpers/Vector512Utilities.cs
index 77dc94475..40e8ac344 100644
--- a/src/ImageSharp/Common/Helpers/Vector512Utilities.cs
+++ b/src/ImageSharp/Common/Helpers/Vector512Utilities.cs
@@ -145,7 +145,15 @@ internal static class Vector512Utilities
     public static Vector512<float> MultiplyAdd(
         Vector512<float> va,
         Vector512<float> vm0,
-        Vector512<float> vm1) => va + (vm0 * vm1);
+        Vector512<float> vm1)
+    {
+        if (Avx512F.IsSupported)
+        {
+            return Avx512F.FusedMultiplyAdd(vm0, vm1, va);
+        }
+
+        return va + (vm0 * vm1);
+    }
 
     [DoesNotReturn]
     private static void ThrowUnreachableException() => throw new UnreachableException();