Merge pull request #201 from Drawaes/master

Reduce register pressure

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

@@ -255,6 +255,31 @@ namespace ImageSharp.Formats.Jpg
             this.V7R *= scaleVec;
         }
 
+        /// <summary>
+        /// Multiply all elements of the block.
+        /// </summary>
+        /// <param name="scaleVec">Vector to multiply by</param>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void MultiplyAllInplace(float scaleVec)
+        {
+            this.V0L *= scaleVec;
+            this.V0R *= scaleVec;
+            this.V1L *= scaleVec;
+            this.V1R *= scaleVec;
+            this.V2L *= scaleVec;
+            this.V2R *= scaleVec;
+            this.V3L *= scaleVec;
+            this.V3R *= scaleVec;
+            this.V4L *= scaleVec;
+            this.V4R *= scaleVec;
+            this.V5L *= scaleVec;
+            this.V5R *= scaleVec;
+            this.V6L *= scaleVec;
+            this.V6R *= scaleVec;
+            this.V7L *= scaleVec;
+            this.V7R *= scaleVec;
+        }
+
         /// <summary>
         /// Adds a vector to all elements of the block.
         /// </summary>

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

@@ -15,31 +15,31 @@ namespace ImageSharp.Formats.Jpg
     internal static class DCT
     {
 #pragma warning disable SA1310 // FieldNamesMustNotContainUnderscore
-        private static readonly Vector4 C_1_175876 = new Vector4(1.175876f);
+        private static readonly float C_1_175876 = 1.175876f;
 
-        private static readonly Vector4 C_1_961571 = new Vector4(-1.961571f);
+        private static readonly float C_1_961571 = -1.961571f;
 
-        private static readonly Vector4 C_0_390181 = new Vector4(-0.390181f);
+        private static readonly float C_0_390181 = -0.390181f;
 
-        private static readonly Vector4 C_0_899976 = new Vector4(-0.899976f);
+        private static readonly float C_0_899976 = -0.899976f;
 
-        private static readonly Vector4 C_2_562915 = new Vector4(-2.562915f);
+        private static readonly float C_2_562915 = -2.562915f;
 
-        private static readonly Vector4 C_0_298631 = new Vector4(0.298631f);
+        private static readonly float C_0_298631 = 0.298631f;
 
-        private static readonly Vector4 C_2_053120 = new Vector4(2.053120f);
+        private static readonly float C_2_053120 = 2.053120f;
 
-        private static readonly Vector4 C_3_072711 = new Vector4(3.072711f);
+        private static readonly float C_3_072711 = 3.072711f;
 
-        private static readonly Vector4 C_1_501321 = new Vector4(1.501321f);
+        private static readonly float C_1_501321 = 1.501321f;
 
-        private static readonly Vector4 C_0_541196 = new Vector4(0.541196f);
+        private static readonly float C_0_541196 = 0.541196f;
 
-        private static readonly Vector4 C_1_847759 = new Vector4(-1.847759f);
+        private static readonly float C_1_847759 = -1.847759f;
 
-        private static readonly Vector4 C_0_765367 = new Vector4(0.765367f);
+        private static readonly float C_0_765367 = 0.765367f;
 
-        private static readonly Vector4 C_0_125 = new Vector4(0.1250f);
+        private static readonly float C_0_125 = 0.1250f;
 #pragma warning restore SA1310 // FieldNamesMustNotContainUnderscore
         private static readonly Vector4 InvSqrt2 = new Vector4(0.707107f);
 
@@ -216,26 +216,26 @@ namespace ImageSharp.Formats.Jpg
             d.V0L = c0 + c1;
             d.V4L = c0 - c1;
 
-            Vector4 w0 = new Vector4(0.541196f);
-            Vector4 w1 = new Vector4(1.306563f);
+            float w0 = 0.541196f;
+            float w1 = 1.306563f;
 
             d.V2L = (w0 * c2) + (w1 * c3);
             d.V6L = (w0 * c3) - (w1 * c2);
 
-            w0 = new Vector4(1.175876f);
-            w1 = new Vector4(0.785695f);
+            w0 = 1.175876f;
+            w1 = 0.785695f;
             c3 = (w0 * t4) + (w1 * t7);
             c0 = (w0 * t7) - (w1 * t4);
 
-            w0 = new Vector4(1.387040f);
-            w1 = new Vector4(0.275899f);
+            w0 = 1.387040f;
+            w1 = 0.275899f;
             c2 = (w0 * t5) + (w1 * t6);
             c1 = (w0 * t6) - (w1 * t5);
 
             d.V3L = c0 - c2;
             d.V5L = c3 - c1;
 
-            Vector4 invsqrt2 = new Vector4(0.707107f);
+            float invsqrt2 = 0.707107f;
             c0 = (c0 + c2) * invsqrt2;
             c3 = (c3 + c1) * invsqrt2;
 
@@ -281,19 +281,19 @@ namespace ImageSharp.Formats.Jpg
             d.V0R = c0 + c1;
             d.V4R = c0 - c1;
 
-            Vector4 w0 = new Vector4(0.541196f);
-            Vector4 w1 = new Vector4(1.306563f);
+            float w0 = 0.541196f;
+            float w1 = 1.306563f;
 
             d.V2R = (w0 * c2) + (w1 * c3);
             d.V6R = (w0 * c3) - (w1 * c2);
 
-            w0 = new Vector4(1.175876f);
-            w1 = new Vector4(0.785695f);
+            w0 = 1.175876f;
+            w1 = 0.785695f;
             c3 = (w0 * t4) + (w1 * t7);
             c0 = (w0 * t7) - (w1 * t4);
 
-            w0 = new Vector4(1.387040f);
-            w1 = new Vector4(0.275899f);
+            w0 = 1.387040f;
+            w1 = 0.275899f;
             c2 = (w0 * t5) + (w1 * t6);
             c1 = (w0 * t6) - (w1 * t5);