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stgsharp/StgSharp.Common/HighPerformance/Memory/HLSFAllocator.Level.cs
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3.3 KiB
C#

//-----------------------------------------------------------------------
// -----------------------------------------------------------------------
// file="HLSFAllocator.Level.cs"
// Project: StgSharp
// AuthorGroup: Nitload Space
// Copyright (c) Nitload Space. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the “Software”), to deal in the Software without restriction,
// including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software,
// and to permit persons to whom the Software is furnished to do so,
// subject to the following conditions:
//
// The above copyright notice and
// this permission notice shall be included in all copies
// or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED “AS IS”,
// WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH
// THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
// -----------------------------------------------------------------------
// -----------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading.Tasks;
namespace StgSharp.HighPerformance.Memory
{
public unsafe partial class HybridLayerSegregatedFitAllocator
{
private const int MaxLevel = 9;
private static readonly int[] levelSizeArray = [
64, 256, 1024, 4096, 16384, 65536, 262144, 1048576, 4194304, 16777216
];
public int AlignOfLevel(int bucketLevel)
{
int blockSize = levelSizeArray[bucketLevel];
return int.Min(blockSize, _align);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private int GetLevelFromSize(uint size)
{
/*
* Level sizes: [64, 256, 1024, 4096, 16384, 65536, 262144, 1048576, 4194304, 16777216]
* Pattern: 64 * 4^level = 2^6 * 2^(2*level) = 2^(6+2*level)
*
* For size S, we need: 2^(6+2*level) >= S
* So: 6+2*level >= log2(S)
* Therefore: level >= (log2(S) - 6) / 2
*
* We use hardware LZCNT instruction via BitOperations.LeadingZeroCount
* log2(S) = 31 - LeadingZeroCount(S) for 32-bit values
*/
int log2Size = 31 - BitOperations.LeadingZeroCount(size);
// Calculate level: level = max(0, (log2Size - 6) / 2)
int level = Math.Max(0, (log2Size - 6) / 2);
// caller is responsible for ensuring level is within bounds
return level;
}
}
public enum CommonMemoryAlign : int
{
XMMLevel = 16,
YMMLevel = 32,
ZMMLevel = 64,
ArmNEONLevel = 16,
}
}