internal static uint Unshuffle2(uint x)
{
// "unshuffle" (twice) even bits to low half and odd bits to high half
x = Bits.BitPermuteStep(x, 0x0000FF00U, 8);
x = Bits.BitPermuteStep(x, 0x00F000F0U, 4);
x = Bits.BitPermuteStep(x, 0x0000CCCCU, 14);
x = Bits.BitPermuteStep(x, 0x00AA00AAU, 7);
return(x);
}
internal static uint Unshuffle(uint x)
{
// "unshuffle" even bits to low half and odd bits to high half
x = Bits.BitPermuteStep(x, 0x22222222U, 1);
x = Bits.BitPermuteStep(x, 0x0C0C0C0CU, 2);
x = Bits.BitPermuteStep(x, 0x00F000F0U, 4);
x = Bits.BitPermuteStep(x, 0x0000FF00U, 8);
return(x);
}
internal static uint Shuffle2(uint x)
{
// "shuffle" (twice) low half to even bits and high half to odd bits
x = Bits.BitPermuteStep(x, 0x00AA00AAU, 7);
x = Bits.BitPermuteStep(x, 0x0000CCCCU, 14);
x = Bits.BitPermuteStep(x, 0x00F000F0U, 4);
x = Bits.BitPermuteStep(x, 0x0000FF00U, 8);
return(x);
}
internal static uint Shuffle(uint x)
{
// "shuffle" low half to even bits and high half to odd bits
x = Bits.BitPermuteStep(x, 0x0000FF00U, 8);
x = Bits.BitPermuteStep(x, 0x00F000F0U, 4);
x = Bits.BitPermuteStep(x, 0x0C0C0C0CU, 2);
x = Bits.BitPermuteStep(x, 0x22222222U, 1);
return(x);
}
internal static ulong Expand32to64(uint x)
{
// "shuffle" low half to even bits and high half to odd bits
x = Bits.BitPermuteStep(x, 0x0000FF00U, 8);
x = Bits.BitPermuteStep(x, 0x00F000F0U, 4);
x = Bits.BitPermuteStep(x, 0x0C0C0C0CU, 2);
x = Bits.BitPermuteStep(x, 0x22222222U, 1);
return(((x >> 1) & M32) << 32 | (x & M32));
}
internal static ulong Unshuffle(ulong x)
{
// "unshuffle" even bits to low half and odd bits to high half
x = Bits.BitPermuteStep(x, 0x2222222222222222UL, 1);
x = Bits.BitPermuteStep(x, 0x0C0C0C0C0C0C0C0CUL, 2);
x = Bits.BitPermuteStep(x, 0x00F000F000F000F0UL, 4);
x = Bits.BitPermuteStep(x, 0x0000FF000000FF00UL, 8);
x = Bits.BitPermuteStep(x, 0x00000000FFFF0000UL, 16);
return(x);
}
internal static ulong Shuffle(ulong x)
{
// "shuffle" low half to even bits and high half to odd bits
x = Bits.BitPermuteStep(x, 0x00000000FFFF0000UL, 16);
x = Bits.BitPermuteStep(x, 0x0000FF000000FF00UL, 8);
x = Bits.BitPermuteStep(x, 0x00F000F000F000F0UL, 4);
x = Bits.BitPermuteStep(x, 0x0C0C0C0C0C0C0C0CUL, 2);
x = Bits.BitPermuteStep(x, 0x2222222222222222UL, 1);
return(x);
}
internal static void Expand64To128(ulong x, ulong[] z, int zOff)
{
// "shuffle" low half to even bits and high half to odd bits
x = Bits.BitPermuteStep(x, 0x00000000FFFF0000UL, 16);
x = Bits.BitPermuteStep(x, 0x0000FF000000FF00UL, 8);
x = Bits.BitPermuteStep(x, 0x00F000F000F000F0UL, 4);
x = Bits.BitPermuteStep(x, 0x0C0C0C0C0C0C0C0CUL, 2);
x = Bits.BitPermuteStep(x, 0x2222222222222222UL, 1);
z[zOff] = (x) & M64;
z[zOff + 1] = (x >> 1) & M64;
}
