/*============================================================================= This file is part of FLINT. FLINT is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. FLINT is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with FLINT; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA =============================================================================*/ /****************************************************************************** Copyright (C) 2009 William Hart ******************************************************************************/ #include #include "flint.h" #include "ulong_extras.h" mp_limb_t n_powmod2_ui_preinv(mp_limb_t a, mp_limb_t exp, mp_limb_t n, mp_limb_t ninv) { mp_limb_t x, y; if (n == UWORD(1)) return UWORD(0); x = UWORD(1); y = a; while (exp) { if (exp & 1) x = n_mulmod2_preinv(x, y, n, ninv); exp >>= 1; if (exp) y = n_mulmod2_preinv(y, y, n, ninv); } return x; } mp_limb_t n_powmod2_preinv(mp_limb_t a, mp_limb_signed_t exp, mp_limb_t n, mp_limb_t ninv) { if (exp < WORD(0)) { a = n_invmod(a, n); exp = -exp; } return n_powmod2_ui_preinv(a, exp, n, ninv); }