pin sourceBase in HwIntrinsics ByteToNormalizedFloat

src/ImageSharp/Common/Helpers/SimdUtils.HwIntrinsics.cs

@@ -621,6 +621,8 @@ namespace SixLabors.ImageSharp
             internal static unsafe void ByteToNormalizedFloat(
                 ReadOnlySpan<byte> source,
                 Span<float> dest)
+            {
+                fixed (byte* sourceBase = source)
                 {
                     if (Avx2.IsSupported)
                     {
@@ -628,8 +630,6 @@ namespace SixLabors.ImageSharp
 
                         int n = dest.Length / Vector256<byte>.Count;
 
-                    byte* sourceBase = (byte*)Unsafe.AsPointer(ref MemoryMarshal.GetReference(source));
-
                         ref Vector256<float> destBase =
                             ref Unsafe.As<float, Vector256<float>>(ref MemoryMarshal.GetReference(dest));
 
@@ -663,8 +663,6 @@ namespace SixLabors.ImageSharp
 
                         int n = dest.Length / Vector128<byte>.Count;
 
-                    byte* sourceBase = (byte*)Unsafe.AsPointer(ref MemoryMarshal.GetReference(source));
-
                         ref Vector128<float> destBase =
                             ref Unsafe.As<float, Vector128<float>>(ref MemoryMarshal.GetReference(dest));
 
@@ -709,6 +707,7 @@ namespace SixLabors.ImageSharp
                         }
                     }
                 }
+            }
 
             /// <summary>
             /// <see cref="NormalizedFloatToByteSaturate"/> as many elements as possible, slicing them down (keeping the remainder).