/* Copyright (C) 2009 William Hart Copyright (C) 2011 Fredrik Johansson This file is part of FLINT. FLINT is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License (LGPL) as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. See . */ #include #include "flint.h" #include "ulong_extras.h" #include "fmpz.h" void fmpz_cdiv_q_2exp(fmpz_t f, const fmpz_t g, ulong exp) { fmpz d = *g; if (!COEFF_IS_MPZ(d)) /* g is small */ { fmpz_set_si(f, -((-d) >> FLINT_MIN(exp, FLINT_BITS - 2))); } else /*g is large */ { __mpz_struct * mpz_ptr = _fmpz_promote(f); /* g is already large */ mpz_cdiv_q_2exp(mpz_ptr, COEFF_TO_PTR(d), exp); _fmpz_demote_val(f); /* division may make value small */ } }