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/divexact.c | |
parent | 1db63fcedab0b288820d66e100b1877b1a5a8851 (diff) |
Basic constant folding implementation
Diffstat (limited to 'vendor/gmp-6.3.0/mpz/divexact.c')
-rw-r--r-- | vendor/gmp-6.3.0/mpz/divexact.c | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/vendor/gmp-6.3.0/mpz/divexact.c b/vendor/gmp-6.3.0/mpz/divexact.c new file mode 100644 index 0000000..8336819 --- /dev/null +++ b/vendor/gmp-6.3.0/mpz/divexact.c @@ -0,0 +1,89 @@ +/* mpz_divexact -- finds quotient when known that quot * den == num && den != 0. + +Contributed to the GNU project by Niels Möller. + +Copyright 1991, 1993-1998, 2000-2002, 2005-2007, 2009, 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_divexact (mpz_ptr quot, mpz_srcptr num, mpz_srcptr den) +{ + mp_ptr qp; + mp_size_t qn; + mp_srcptr np, dp; + mp_size_t nn, dn; + TMP_DECL; + +#if WANT_ASSERT + { + mpz_t rem; + mpz_init (rem); + mpz_tdiv_r (rem, num, den); + ASSERT (SIZ(rem) == 0); + mpz_clear (rem); + } +#endif + + nn = ABSIZ (num); + dn = ABSIZ (den); + + if (nn < dn) + { + /* This special case avoids segfaults below when the function is + incorrectly called with |N| < |D|, N != 0. It also handles the + well-defined case N = 0. */ + SIZ(quot) = 0; + return; + } + + qn = nn - dn + 1; + + TMP_MARK; + + if (quot == num || quot == den) + qp = TMP_ALLOC_LIMBS (qn); + else + qp = MPZ_NEWALLOC (quot, qn); + + np = PTR(num); + dp = PTR(den); + + mpn_divexact (qp, np, nn, dp, dn); + MPN_NORMALIZE (qp, qn); + + if (qp != PTR(quot)) + MPN_COPY (MPZ_NEWALLOC (quot, qn), qp, qn); + + SIZ(quot) = (SIZ(num) ^ SIZ(den)) >= 0 ? qn : -qn; + + TMP_FREE; +} |