vpopcnt.cs

vpopcnt.cs

static Vector128<uint> VPopcnt(Vector128<uint> dataArg)
{
    var data = dataArg; // workaround for a codegen issue
    data = Sse2.Subtract(data, Sse2.And(Sse2.ShiftRightLogical(data, 1), Vector128.Create((uint)0x55555555)));
    data = Sse2.Add(Sse2.And(data, Vector128.Create((uint)0x33333333)), 
        Sse2.And(Sse2.ShiftRightLogical(data, 2), Vector128.Create((uint)0x33333333)));
    data = Sse2.And(Sse2.Add(data, Sse2.ShiftRightLogical(data, 4)), Vector128.Create((uint)0x0F0F0F0F));
    data = Sse2.Add(data, Sse2.ShiftRightLogical(data, 8));
    data = Sse2.Add(data, Sse2.ShiftRightLogical(data, 16));
    data = Sse2.And(data, Vector128.Create((uint)0x0000003F));
    return data;
}