Benchmarks extended. Small optimizations.

EvenPerfectBitScanner.Benchmarks/UInt128ExtensionsBenchmarks.cs

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+using System.Numerics;
+using BenchmarkDotNet.Attributes;
+using PerfectNumbers.Core;
+
+namespace EvenPerfectBitScanner.Benchmarks;
+
+[MemoryDiagnoser]
+public class UInt128ExtensionsBenchmarks
+{
+    [Params(3UL, 8191UL, 131071UL, 2147483647UL)]
+    public ulong Value { get; set; }
+
+    [Benchmark(Baseline = true)]
+    public (ulong Mod10, ulong Mod8, ulong Mod3, ulong Mod5) LegacyModulo()
+    {
+		ulong mod10, mod8, mod3, mod5;
+		UInt128 zero = UInt128.Zero;
+		if (Value == zero)
+		{
+			mod3 = 0UL;
+			mod5 = 0UL;
+			mod8 = 0UL;
+			mod10 = 0UL;
+			return (mod10, mod8, mod3, mod5);
+		}
+
+		UInt128 high = Value >> 64;
+		ulong result = Value;
+		mod8 = result & 7UL;
+		// 2^64 ≡ 1 (mod 3)
+		ulong modRem = (result % 3UL) + ((ulong)high % 3UL);
+		mod3 = modRem >= 3UL ? modRem - 3UL : modRem;
+		// 2^64 ≡ 1 (mod 5)
+		modRem = (result % 5UL) + ((ulong)high % 5UL);
+		mod5 = modRem >= 5UL ? modRem - 5UL : modRem;
+
+		while (high != zero)
+		{
+			// 2^64 ≡ 6 (mod 10)
+			result = (result + (ulong)high * 6UL) % 10UL;
+			high >>= 64;
+		}
+
+		mod10 = result % 10UL;
+        return (mod10, mod8, mod3, mod5);
+    }
+
+    [Benchmark]
+    public (ulong Mod10, ulong Mod8, ulong Mod3, ulong Mod5) ModMethodModulo()
+    {
+        Value.Mod10_8_5_3(out ulong mod10, out ulong mod8, out ulong mod5, out ulong mod3);
+        return (mod10, mod8, mod3, mod5);
+    }
+}
+