diff options
Diffstat (limited to 'rts/gmp/mpz/tdiv_q_2exp.c')
-rw-r--r-- | rts/gmp/mpz/tdiv_q_2exp.c | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/rts/gmp/mpz/tdiv_q_2exp.c b/rts/gmp/mpz/tdiv_q_2exp.c new file mode 100644 index 0000000000..03d1e01f89 --- /dev/null +++ b/rts/gmp/mpz/tdiv_q_2exp.c @@ -0,0 +1,68 @@ +/* mpz_tdiv_q_2exp -- Divide an integer by 2**CNT. Round the quotient + towards -infinity. + +Copyright (C) 1991, 1993, 1994, 1996 Free Software Foundation, Inc. + +This file is part of the GNU MP Library. + +The GNU MP Library is free software; you can redistribute it and/or modify +it under the terms of the GNU Lesser General Public License as published by +the Free Software Foundation; either version 2.1 of the License, or (at your +option) any later version. + +The GNU MP Library 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 Lesser General Public +License for more details. + +You should have received a copy of the GNU Lesser General Public License +along with the GNU MP Library; see the file COPYING.LIB. If not, write to +the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, +MA 02111-1307, USA. */ + +#include "gmp.h" +#include "gmp-impl.h" + +void +#if __STDC__ +mpz_tdiv_q_2exp (mpz_ptr w, mpz_srcptr u, unsigned long int cnt) +#else +mpz_tdiv_q_2exp (w, u, cnt) + mpz_ptr w; + mpz_srcptr u; + unsigned long int cnt; +#endif +{ + mp_size_t usize, wsize; + mp_size_t limb_cnt; + + usize = u->_mp_size; + limb_cnt = cnt / BITS_PER_MP_LIMB; + wsize = ABS (usize) - limb_cnt; + if (wsize <= 0) + w->_mp_size = 0; + else + { + mp_ptr wp; + mp_srcptr up; + + if (w->_mp_alloc < wsize) + _mpz_realloc (w, wsize); + + wp = w->_mp_d; + up = u->_mp_d; + + cnt %= BITS_PER_MP_LIMB; + if (cnt != 0) + { + mpn_rshift (wp, up + limb_cnt, wsize, cnt); + wsize -= wp[wsize - 1] == 0; + } + else + { + MPN_COPY_INCR (wp, up + limb_cnt, wsize); + } + + w->_mp_size = usize >= 0 ? wsize : -wsize; + } +} |