Ryujinx/Ryujinx.Common/BitUtils.cs

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namespace Ryujinx.Common
{
public static class BitUtils
{
private static readonly byte[] ClzNibbleTbl = { 4, 3, 2, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0 };
public static int AlignUp(int value, int size)
{
return (value + (size - 1)) & -size;
}
public static ulong AlignUp(ulong value, int size)
{
return (ulong)AlignUp((long)value, size);
}
public static long AlignUp(long value, int size)
{
return (value + (size - 1)) & -(long)size;
}
public static int AlignDown(int value, int size)
{
return value & -size;
}
public static ulong AlignDown(ulong value, int size)
{
return (ulong)AlignDown((long)value, size);
}
public static long AlignDown(long value, int size)
{
return value & -(long)size;
}
public static ulong DivRoundUp(ulong value, uint dividend)
{
return (value + dividend - 1) / dividend;
}
public static long DivRoundUp(long value, int dividend)
{
return (value + dividend - 1) / dividend;
}
public static bool IsPowerOfTwo32(int value)
{
return value != 0 && (value & (value - 1)) == 0;
}
public static bool IsPowerOfTwo64(long value)
{
return value != 0 && (value & (value - 1)) == 0;
}
public static int CountLeadingZeros32(int value)
{
return (int)CountLeadingZeros((ulong)value, 32);
}
public static int CountLeadingZeros64(long value)
{
return (int)CountLeadingZeros((ulong)value, 64);
}
private static ulong CountLeadingZeros(ulong value, int size)
{
if (value == 0ul)
{
return (ulong)size;
}
int nibbleIdx = size;
int preCount, count = 0;
do
{
nibbleIdx -= 4;
preCount = ClzNibbleTbl[(value >> nibbleIdx) & 0b1111];
count += preCount;
}
while (preCount == 4);
return (ulong)count;
}
public static long ReverseBits64(long value)
{
return (long)ReverseBits64((ulong)value);
}
private static ulong ReverseBits64(ulong value)
{
value = ((value & 0xaaaaaaaaaaaaaaaa) >> 1 ) | ((value & 0x5555555555555555) << 1 );
value = ((value & 0xcccccccccccccccc) >> 2 ) | ((value & 0x3333333333333333) << 2 );
value = ((value & 0xf0f0f0f0f0f0f0f0) >> 4 ) | ((value & 0x0f0f0f0f0f0f0f0f) << 4 );
value = ((value & 0xff00ff00ff00ff00) >> 8 ) | ((value & 0x00ff00ff00ff00ff) << 8 );
value = ((value & 0xffff0000ffff0000) >> 16) | ((value & 0x0000ffff0000ffff) << 16);
return (value >> 32) | (value << 32);
}
}
}