diff options
author | Thomas Voss <mail@thomasvoss.com> | 2024-06-21 23:36:36 +0200 |
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committer | Thomas Voss <mail@thomasvoss.com> | 2024-06-21 23:42:26 +0200 |
commit | a89a14ef5da44684a16b204e7a70460cc8c4922a (patch) | |
tree | b23b4c6b155977909ef508fdae2f48d33d802813 /vendor/gmp-6.3.0/mpz/mul_2exp.c | |
parent | 1db63fcedab0b288820d66e100b1877b1a5a8851 (diff) |
Basic constant folding implementation
Diffstat (limited to 'vendor/gmp-6.3.0/mpz/mul_2exp.c')
-rw-r--r-- | vendor/gmp-6.3.0/mpz/mul_2exp.c | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/vendor/gmp-6.3.0/mpz/mul_2exp.c b/vendor/gmp-6.3.0/mpz/mul_2exp.c new file mode 100644 index 0000000..6144d0d --- /dev/null +++ b/vendor/gmp-6.3.0/mpz/mul_2exp.c @@ -0,0 +1,72 @@ +/* mpz_mul_2exp -- Multiply a bignum by 2**CNT + +Copyright 1991, 1993, 1994, 1996, 2001, 2002, 2012 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 either: + + * the GNU Lesser General Public License as published by the Free + Software Foundation; either version 3 of the License, or (at your + option) any later version. + +or + + * 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. + +or both in parallel, as here. + +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 copies of the GNU General Public License and the +GNU Lesser General Public License along with the GNU MP Library. If not, +see https://www.gnu.org/licenses/. */ + +#include "gmp-impl.h" + +void +mpz_mul_2exp (mpz_ptr r, mpz_srcptr u, mp_bitcnt_t cnt) +{ + mp_size_t un, rn; + mp_size_t limb_cnt; + mp_ptr rp; + mp_srcptr up; + mp_limb_t rlimb; + + un = ABSIZ (u); + limb_cnt = cnt / GMP_NUMB_BITS; + rn = un + limb_cnt; + + if (un == 0) + rn = 0; + else + { + rp = MPZ_REALLOC (r, rn + 1); + up = PTR(u); + + cnt %= GMP_NUMB_BITS; + if (cnt != 0) + { + rlimb = mpn_lshift (rp + limb_cnt, up, un, cnt); + rp[rn] = rlimb; + rn += (rlimb != 0); + } + else + { + MPN_COPY_DECR (rp + limb_cnt, up, un); + } + + /* Zero all whole limbs at low end. Do it here and not before calling + mpn_lshift, not to lose for U == R. */ + MPN_ZERO (rp, limb_cnt); + } + + SIZ(r) = SIZ(u) >= 0 ? rn : -rn; +} |