Reapply modulo helpers and inline fast remainders

EvenPerfectBitScanner.Benchmarks/Mod6ComparisonBenchmarks.cs

@@ -0,0 +1,81 @@
+using System.Numerics;
+using BenchmarkDotNet.Attributes;
+using BenchmarkDotNet.Jobs;
+using PerfectNumbers.Core;
+
+namespace EvenPerfectBitScanner.Benchmarks;
+
+[SimpleJob(RuntimeMoniker.Net80, launchCount: 1, warmupCount: 1, iterationCount: 3)]
+[MemoryDiagnoser]
+public class Mod6ComparisonBenchmarks
+{
+    private const int Iterations = 10_000_000;
+    private const ulong Divisor = 6UL;
+    private static readonly ulong FastDivMul = (ulong)(((UInt128)1 << 64) / Divisor);
+
+    [Params(3UL, 131071UL, ulong.MaxValue - 1024UL)]
+    public ulong StartValue { get; set; }
+
+    [Benchmark(Baseline = true, OperationsPerInvoke = Iterations)]
+    public ulong ModuloOperator()
+    {
+        ulong checksum = 0UL;
+        ulong value = StartValue;
+
+        for (int i = 0; i < Iterations; i++)
+        {
+            checksum += value % Divisor;
+            value += (ulong)((i & 15) + 1);
+        }
+
+        return checksum;
+    }
+
+    [Benchmark(OperationsPerInvoke = Iterations)]
+    public ulong DivisionBased()
+    {
+        ulong checksum = 0UL;
+        ulong value = StartValue;
+
+        for (int i = 0; i < Iterations; i++)
+        {
+            ulong quotient = value / Divisor;
+            checksum += value - quotient * Divisor;
+            value += (ulong)((i & 15) + 1);
+        }
+
+        return checksum;
+    }
+
+    [Benchmark(OperationsPerInvoke = Iterations)]
+    public ulong FastDivHigh()
+    {
+        ulong checksum = 0UL;
+        ulong value = StartValue;
+
+        for (int i = 0; i < Iterations; i++)
+        {
+            ulong quotient = value.FastDiv64(Divisor, FastDivMul);
+            checksum += value - quotient * Divisor;
+            value += (ulong)((i & 15) + 1);
+        }
+
+        return checksum;
+    }
+
+    [Benchmark(OperationsPerInvoke = Iterations)]
+    public ulong ExtensionMethod()
+    {
+        ulong checksum = 0UL;
+        ulong value = StartValue;
+
+        for (int i = 0; i < Iterations; i++)
+        {
+            checksum += value.Mod6();
+            value += (ulong)((i & 15) + 1);
+        }
+
+        return checksum;
+    }
+}
+