All Vector128 Load

Author: JimBobSquarePants

src/ImageSharp/Formats/Jpeg/Components/Block8x8F.Vector128.cs

@@ -40,6 +40,36 @@ public void NormalizeColorsAndRoundInPlaceVector128(float maximum)
         this.V7R = NormalizeAndRoundVector128(this.V7R.AsVector128(), off, max).AsVector4();
     }
 
+    /// <summary>
+    /// Loads values from <paramref name="source"/> using extended AVX2 intrinsics.
+    /// </summary>
+    /// <param name="source">The source <see cref="Block8x8"/></param>
+    public void LoadFromInt16ExtendedVector128(ref Block8x8 source)
+    {
+        DebugGuard.IsTrue(Vector128.IsHardwareAccelerated, "Vector128 support is required to run this operation!");
+
+        ref Vector128<short> srcBase = ref Unsafe.As<Block8x8, Vector128<short>>(ref source);
+        ref Vector128<float> destBase = ref Unsafe.As<Block8x8F, Vector128<float>>(ref this);
+
+        // Only 8 iterations, one per 128b short block
+        for (nuint i = 0; i < 8; i++)
+        {
+            Vector128<short> src = Unsafe.Add(ref srcBase, i);
+
+            // Step 1: Widen short -> int
+            Vector128<int> lower = Vector128.WidenLower(src); // lower 4 shorts -> 4 ints
+            Vector128<int> upper = Vector128.WidenUpper(src); // upper 4 shorts -> 4 ints
+
+            // Step 2: Convert int -> float
+            Vector128<float> lowerF = Vector128.ConvertToSingle(lower);
+            Vector128<float> upperF = Vector128.ConvertToSingle(upper);
+
+            // Step 3: Store to destination (this is 16 lanes -> two Vector128<float> blocks)
+            Unsafe.Add(ref destBase, (i * 2) + 0) = lowerF;
+            Unsafe.Add(ref destBase, (i * 2) + 1) = upperF;
+        }
+    }
+
     [MethodImpl(InliningOptions.ShortMethod)]
     private static Vector128<float> NormalizeAndRoundVector128(Vector128<float> value, Vector128<float> off, Vector128<float> max)
         => Vector128_.RoundToNearestInteger(Vector128_.Clamp(value + off, Vector128<float>.Zero, max));

src/ImageSharp/Formats/Jpeg/Components/Block8x8F.cs

@@ -392,6 +392,11 @@ public void LoadFrom(ref Block8x8 source)
             this.LoadFromInt16ExtendedAvx2(ref source);
             return;
         }
+        else if (Vector128.IsHardwareAccelerated)
+        {
+            this.LoadFromInt16ExtendedVector128(ref source);
+            return;
+        }
 
         this.LoadFromInt16Scalar(ref source);
     }

tests/ImageSharp.Tests/Formats/Jpg/Block8x8FTests.cs

@@ -55,7 +55,7 @@ public void Indexer()
             Times,
             () =>
             {
-                var block = default(Block8x8F);
+                Block8x8F block = default;
 
                 for (int i = 0; i < Block8x8F.Size; i++)
                 {
@@ -68,7 +68,7 @@ public void Indexer()
                     sum += block[i];
                 }
             });
-        Assert.Equal(sum, 64f * 63f * 0.5f);
+        Assert.Equal(64f * 63f * 0.5f, sum);
     }
 
     [Fact]
@@ -93,7 +93,7 @@ public void Indexer_ReferenceBenchmarkWithArray()
                     sum += block[i];
                 }
             });
-        Assert.Equal(sum, 64f * 63f * 0.5f);
+        Assert.Equal(64f * 63f * 0.5f, sum);
     }
 
     [Fact]
@@ -121,7 +121,7 @@ public void Load_Store_FloatArray()
     }
 
     [Fact]
-    public void TransposeInplace()
+    public void TransposeInPlace()
     {
         static void RunTest()
         {
@@ -276,7 +276,7 @@ public void RoundInto()
         float[] data = Create8x8RandomFloatData(-1000, 1000);
 
         Block8x8F source = Block8x8F.Load(data);
-        var dest = default(Block8x8);
+        Block8x8 dest = default;
 
         source.RoundInto(ref dest);
 
@@ -388,7 +388,7 @@ public void LoadFromUInt16Scalar()
 
         short[] data = Create8x8ShortData();
 
-        var source = Block8x8.Load(data);
+        Block8x8 source = Block8x8.Load(data);
 
         Block8x8F dest = default;
         dest.LoadFromInt16Scalar(ref source);
@@ -399,6 +399,27 @@ public void LoadFromUInt16Scalar()
         }
     }
 
+    [Fact]
+    public void LoadFromUInt16ExtendedVector128()
+    {
+        if (this.SkipOnNonVector128Runner())
+        {
+            return;
+        }
+
+        short[] data = Create8x8ShortData();
+
+        Block8x8 source = Block8x8.Load(data);
+
+        Block8x8F dest = default;
+        dest.LoadFromInt16ExtendedVector128(ref source);
+
+        for (int i = 0; i < Block8x8F.Size; i++)
+        {
+            Assert.Equal(data[i], dest[i]);
+        }
+    }
+
     [Fact]
     public void LoadFromUInt16ExtendedAvx2()
     {
@@ -409,7 +430,7 @@ public void LoadFromUInt16ExtendedAvx2()
 
         short[] data = Create8x8ShortData();
 
-        var source = Block8x8.Load(data);
+        Block8x8 source = Block8x8.Load(data);
 
         Block8x8F dest = default;
         dest.LoadFromInt16ExtendedAvx2(ref source);