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using System;
using System.Numerics;
namespace ARMeilleure.Common
{
static class BitUtils
{
private static ReadOnlySpan<sbyte> HbsNibbleLut => new sbyte[] { -1, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3 };
public static long FillWithOnes(int bits)
{
return bits == 64 ? -1L : (1L << bits) - 1;
}
public static int HighestBitSet(int value)
{
return 31 - BitOperations.LeadingZeroCount((uint)value);
}
public static int HighestBitSetNibble(int value)
{
return HbsNibbleLut[value];
}
public static long Replicate(long bits, int size)
{
long output = 0;
for (int bit = 0; bit < 64; bit += size)
{
output |= bits << bit;
}
return output;
}
public static int RotateRight(int bits, int shift, int size)
{
return (int)RotateRight((uint)bits, shift, size);
}
public static uint RotateRight(uint bits, int shift, int size)
{
return (bits >> shift) | (bits << (size - shift));
}
public static long RotateRight(long bits, int shift, int size)
{
return (long)RotateRight((ulong)bits, shift, size);
}
public static ulong RotateRight(ulong bits, int shift, int size)
{
return (bits >> shift) | (bits << (size - shift));
}
}
}
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