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even-perfect-numbers-scanner/EvenPerfectBitScanner.Benchmarks/Mod3Benchmarks.cs

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using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Jobs;
using PerfectNumbers.Core;
namespace EvenPerfectBitScanner.Benchmarks;
[SimpleJob(RuntimeMoniker.Net80, launchCount: 1, warmupCount: 1, iterationCount: 5)]
[MemoryDiagnoser]
public class Mod3Benchmarks
{
private static readonly ModBenchmarkCase[] Cases =
[
new(ModNumericType.UInt32, 3U, "UInt32:3"),
new(ModNumericType.UInt32, 2047U, "UInt32:2047"),
new(ModNumericType.UInt32, 65535U, "UInt32:65535"),
new(ModNumericType.UInt32, 2147483647U, "UInt32:2147483647"),
new(ModNumericType.UInt64, 3UL, "UInt64:3"),
new(ModNumericType.UInt64, 8191UL, "UInt64:8191"),
new(ModNumericType.UInt64, 131071UL, "UInt64:131071"),
new(ModNumericType.UInt64, 2147483647UL, "UInt64:2147483647"),
new(ModNumericType.UInt64, ulong.MaxValue - 17UL, "UInt64:Max-17"),
new(ModNumericType.UInt128, 3UL, "UInt128:3"),
new(ModNumericType.UInt128, 8191UL, "UInt128:8191"),
new(ModNumericType.UInt128, 131071UL, "UInt128:131071"),
new(ModNumericType.UInt128, 2147483647UL, "UInt128:2147483647"),
new(ModNumericType.UInt128, ulong.MaxValue - 17UL, "UInt128:Max-17"),
];
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static ulong Mod3(ulong value) =>
((uint)(value & ULongExtensions.WordBitMask)
+ (uint)((value >> 16) & ULongExtensions.WordBitMask)
+ (uint)((value >> 32) & ULongExtensions.WordBitMask)
+ (uint)((value >> 48) & ULongExtensions.WordBitMask)) % 3UL;
public static IEnumerable<ModBenchmarkCase> GetCases() => Cases;
/// <summary>
/// `% 3` baseline across all widths; previously landed at 0.03-0.09 ns on <c>uint</c>, 0.26-0.49 ns on <c>ulong</c>,
/// and 2.88-2.97 ns on <see cref="UInt128"/> inputs throughout the merged dataset.
/// </summary>
[Benchmark(Baseline = true)]
[ArgumentsSource(nameof(GetCases))]
public ulong ModuloOperator(ModBenchmarkCase data)
{
return data.Type switch
{
ModNumericType.UInt32 => (uint)data.Value % 3U,
ModNumericType.UInt64 => (ulong)data.Value % 3UL,
ModNumericType.UInt128 => (ulong)(data.Value % 3UL),
_ => throw new ArgumentOutOfRangeException(nameof(data)),
};
}
/// <summary>
/// Extension helpers that fold operands by width; they matched the modulo noise floor on <c>uint</c>, trailed by
/// ~1.5-1.7× on <c>ulong</c>, and delivered a 6.4× speedup on <see cref="UInt128"/>.
/// </summary>
[Benchmark]
[ArgumentsSource(nameof(GetCases))]
public ulong ExtensionMethod(ModBenchmarkCase data)
{
return data.Type switch
{
ModNumericType.UInt32 => UIntExtensions.Mod3((uint)data.Value),
ModNumericType.UInt64 => Mod3((ulong)data.Value),
ModNumericType.UInt128 => data.Value.Mod3(),
_ => throw new ArgumentOutOfRangeException(nameof(data)),
};
}
}