diff options
Diffstat (limited to 'gnu/lib/libgmp/mpz_div_2exp.c')
-rw-r--r-- | gnu/lib/libgmp/mpz_div_2exp.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/gnu/lib/libgmp/mpz_div_2exp.c b/gnu/lib/libgmp/mpz_div_2exp.c new file mode 100644 index 0000000..de67f2f --- /dev/null +++ b/gnu/lib/libgmp/mpz_div_2exp.c @@ -0,0 +1,53 @@ +/* mpz_div_2exp -- Divide a bignum by 2**CNT + +Copyright (C) 1991 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 General Public License as published by +the Free Software Foundation; either version 2, 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 General Public License for more details. + +You should have received a copy of the GNU General Public License +along with the GNU MP Library; see the file COPYING. If not, write to +the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ + +#include "gmp.h" +#include "gmp-impl.h" + +void +#ifdef __STDC__ +mpz_div_2exp (MP_INT *w, const MP_INT *u, unsigned long int cnt) +#else +mpz_div_2exp (w, u, cnt) + MP_INT *w; + const MP_INT *u; + unsigned long int cnt; +#endif +{ + mp_size usize = u->size; + mp_size wsize; + mp_size abs_usize = ABS (usize); + mp_size limb_cnt; + + limb_cnt = cnt / BITS_PER_MP_LIMB; + wsize = abs_usize - limb_cnt; + if (wsize <= 0) + wsize = 0; + else + { + if (w->alloc < wsize) + _mpz_realloc (w, wsize); + + wsize = mpn_rshift (w->d, u->d + limb_cnt, abs_usize - limb_cnt, + cnt % BITS_PER_MP_LIMB); + } + + w->size = (usize >= 0) ? wsize : -wsize; +} |