1/* mpc_ceil_log2 - returns ceil(log(d)/log(2)) 2 3Copyright (C) 2004, 2009, 2010 INRIA 4 5This file is part of GNU MPC. 6 7GNU MPC is free software; you can redistribute it and/or modify it under 8the terms of the GNU Lesser General Public License as published by the 9Free Software Foundation; either version 3 of the License, or (at your 10option) any later version. 11 12GNU MPC is distributed in the hope that it will be useful, but WITHOUT ANY 13WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 14FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for 15more details. 16 17You should have received a copy of the GNU Lesser General Public License 18along with this program. If not, see http://www.gnu.org/licenses/ . 19*/ 20 21#include "mpc-impl.h" 22 23/* returns ceil(log(d)/log(2)) if d > 0 */ 24/* Don't use count_leading_zeros since it is in longlong.h */ 25mpfr_prec_t 26mpc_ceil_log2 (mpfr_prec_t d) 27{ 28 mpfr_prec_t exp; 29 30 for (exp = 0; d > 1; d = (d + 1) / 2) 31 exp++; 32 return exp; 33} 34