1 /* mpc_ceil_log2 - returns ceil(log(d)/log(2)) 2 3 Copyright (C) 2004, 2009, 2010 INRIA 4 5 This file is part of GNU MPC. 6 7 GNU MPC is free software; you can redistribute it and/or modify it under 8 the terms of the GNU Lesser General Public License as published by the 9 Free Software Foundation; either version 3 of the License, or (at your 10 option) any later version. 11 12 GNU MPC is distributed in the hope that it will be useful, but WITHOUT ANY 13 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 14 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for 15 more details. 16 17 You should have received a copy of the GNU Lesser General Public License 18 along 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 */ 25 mpfr_prec_t 26 mpc_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