From 636ae6a4dc7c634f76e4f0d67cb050e37b42c6f3 Mon Sep 17 00:00:00 2001
From: nix <code.03bb@gmail.com>
Date: Thu, 11 Sep 2025 19:16:34 +0200
Subject: [PATCH] add mandelbrot 5.cs

---
 bench/algorithm/mandelbrot/5.cs | 105 ++++++++++++++++++++++++++++++++
 1 file changed, 105 insertions(+)
 create mode 100644 bench/algorithm/mandelbrot/5.cs

diff --git a/bench/algorithm/mandelbrot/5.cs b/bench/algorithm/mandelbrot/5.cs
new file mode 100644
index 000000000..7dd2154db
--- /dev/null
+++ b/bench/algorithm/mandelbrot/5.cs
@@ -0,0 +1,105 @@
+using System.Runtime.CompilerServices;
+using System.Runtime.Intrinsics;
+using System.Runtime.Intrinsics.X86;
+using System.Security.Cryptography;
+
+namespace mandelbrot;
+
+public static class MandelBrot
+{
+    public static void Main(string[] args)
+    {
+        int size = args.Length == 0 ? 200 : int.Parse(args[0]);
+        size = (size + 7) / 8 * 8;
+        int rowBytes = size / 8;
+        double inv = 2.0 / size;
+
+        Console.WriteLine($"P4\n{size} {size}");
+
+
+        byte[] data = new byte[size * rowBytes];
+
+        // Constants
+        Vector256<double> idx4 = Vector256.Create(0.0, 1.0, 2.0, 3.0);
+        Vector256<double> four = Vector256.Create(4.0);
+        Vector256<double> invV = Vector256.Create(inv);
+        Vector256<double> neg1_5 = Vector256.Create(-1.5);
+
+        Parallel.For(0, size, y =>
+        {
+            double ciScalar = y * inv - 1.0;
+            Vector256<double> ci = Vector256.Create(ciScalar);
+
+            for (int xb = 0; xb < rowBytes; xb++)
+            {
+                double baseX = xb * 8.0;
+
+
+                Vector256<double> cr0 = Vector256.Add(
+                    Vector256.Multiply(
+                        Vector256.Add(idx4, Vector256.Create(baseX)), invV),
+                    neg1_5);
+                Vector256<double> cr1 = Vector256.Add(
+                    Vector256.Multiply(
+                        Vector256.Add(idx4, Vector256.Create(baseX + 4.0)), invV),
+                    neg1_5);
+
+                byte hi = MBrot4Block5Mask(cr0, ci, four, hiNibble: true);
+                byte lo = MBrot4Block5Mask(cr1, ci, four, hiNibble: false);
+                data[y * rowBytes + xb] = (byte)(hi | lo);
+            }
+        });
+        byte[] hash = MD5.HashData(data.AsSpan());
+        Console.WriteLine(Convert.ToHexString(hash.AsSpan()).ToLowerInvariant());
+    }
+
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+    private static byte MBrot4Block5Mask( Vector256<double> cr, Vector256<double> ci, Vector256<double> four, bool hiNibble)
+    {
+        Vector256<double> zr = Vector256<double>.Zero;
+        Vector256<double> zi = Vector256<double>.Zero;
+        Vector256<double> tr = Vector256<double>.Zero;
+        Vector256<double> ti = Vector256<double>.Zero;
+        Vector256<double> inside = Vector256<long>.Zero.AsDouble();
+
+        for (int outer = 0; outer < 10; outer++)
+        {
+            for (int j = 0; j < 5; j++)
+            {
+                // zi = (zr + zr) * zi + ci;
+                Vector256<double> twoZr = Vector256.Add(zr, zr);
+                zi = Vector256.Add(Vector256.Multiply(twoZr, zi), ci);
+
+                // zr = tr - ti + cr; (tr, ti from previous sub-iteration)
+                zr = Vector256.Add(Vector256.Subtract(tr, ti), cr);
+
+                // tr = zr*zr; ti = zi*zi;
+                tr = Vector256.Multiply(zr, zr);
+                ti = Vector256.Multiply(zi, zi);
+            }
+
+            Vector256<double> abs2 = Vector256.Add(tr, ti);
+            inside = Vector256.LessThanOrEqual(abs2, four).AsDouble();
+        }
+
+        int m = Avx.MoveMask(inside);
+
+        if (hiNibble)
+        {
+            return (byte)(
+                ((m & 1) << 7) |
+                ((m & 2) << 5) |
+                ((m & 4) << 3) |
+                ((m & 8) << 1)
+            );
+        }
+
+        return (byte)(
+            ((m & 1) << 3) |
+            ((m & 2) << 1) |
+            ((m & 4) >> 1) |
+            ((m & 8) >> 3)
+        );
+    }
+}
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