diff options
author | Niels Provos <provos@cvs.openbsd.org> | 1997-06-24 21:28:32 +0000 |
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committer | Niels Provos <provos@cvs.openbsd.org> | 1997-06-24 21:28:32 +0000 |
commit | 2797d26f259dcf820a086e4110ca53c2db78bc5d (patch) | |
tree | fa8f850d5b10a0f6fab21154cc60c759de02ddb2 /gnu/lib/libgmp/mpz/mul_2exp.c | |
parent | 6d71925e98a49e80463b5f54135da67389b7ddea (diff) |
import of libgmp-2.0.2. Makefile.bsd-wrappers need to be worked on.
Diffstat (limited to 'gnu/lib/libgmp/mpz/mul_2exp.c')
-rw-r--r-- | gnu/lib/libgmp/mpz/mul_2exp.c | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/gnu/lib/libgmp/mpz/mul_2exp.c b/gnu/lib/libgmp/mpz/mul_2exp.c new file mode 100644 index 00000000000..4d66a9877e3 --- /dev/null +++ b/gnu/lib/libgmp/mpz/mul_2exp.c @@ -0,0 +1,76 @@ +/* mpz_mul_2exp -- Multiply a bignum by 2**CNT + +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 Library General Public License as published by +the Free Software Foundation; either version 2 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 Library General Public +License for more details. + +You should have received a copy of the GNU Library 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_mul_2exp (mpz_ptr w, mpz_srcptr u, unsigned long int cnt) +#else +mpz_mul_2exp (w, u, cnt) + mpz_ptr w; + mpz_srcptr u; + unsigned long int cnt; +#endif +{ + mp_size_t usize = u->_mp_size; + mp_size_t abs_usize = ABS (usize); + mp_size_t wsize; + mp_size_t limb_cnt; + mp_ptr wp; + mp_limb_t wlimb; + + if (usize == 0) + { + w->_mp_size = 0; + return; + } + + limb_cnt = cnt / BITS_PER_MP_LIMB; + wsize = abs_usize + limb_cnt + 1; + if (w->_mp_alloc < wsize) + _mpz_realloc (w, wsize); + + wp = w->_mp_d; + wsize = abs_usize + limb_cnt; + + cnt %= BITS_PER_MP_LIMB; + if (cnt != 0) + { + wlimb = mpn_lshift (wp + limb_cnt, u->_mp_d, abs_usize, cnt); + if (wlimb != 0) + { + wp[wsize] = wlimb; + wsize++; + } + } + else + { + MPN_COPY_DECR (wp + limb_cnt, u->_mp_d, abs_usize); + } + + /* Zero all whole limbs at low end. Do it here and not before calling + mpn_lshift, not to lose for U == W. */ + MPN_ZERO (wp, limb_cnt); + + w->_mp_size = usize >= 0 ? wsize : -wsize; +} |