From 11da511c784eca003deb90c23570f0873954e0de Mon Sep 17 00:00:00 2001 From: Duncan Wilkie Date: Sat, 18 Nov 2023 06:11:09 -0600 Subject: Initial commit. --- gmp-6.3.0/mpn/generic/sbpi1_bdiv_qr.c | 82 +++++++++++++++++++++++++++++++++++ 1 file changed, 82 insertions(+) create mode 100644 gmp-6.3.0/mpn/generic/sbpi1_bdiv_qr.c (limited to 'gmp-6.3.0/mpn/generic/sbpi1_bdiv_qr.c') diff --git a/gmp-6.3.0/mpn/generic/sbpi1_bdiv_qr.c b/gmp-6.3.0/mpn/generic/sbpi1_bdiv_qr.c new file mode 100644 index 0000000..6146c45 --- /dev/null +++ b/gmp-6.3.0/mpn/generic/sbpi1_bdiv_qr.c @@ -0,0 +1,82 @@ +/* mpn_sbpi1_bdiv_qr -- schoolbook Hensel division with precomputed inverse, + returning quotient and remainder. + + Contributed to the GNU project by Niels Möller and Torbjörn Granlund. + + THE FUNCTIONS IN THIS FILE ARE INTERNAL FUNCTIONS WITH MUTABLE INTERFACES. + IT IS ONLY SAFE TO REACH THEM THROUGH DOCUMENTED INTERFACES. IN FACT, IT IS + ALMOST GUARANTEED THAT THEY'LL CHANGE OR DISAPPEAR IN A FUTURE GMP RELEASE. + +Copyright 2006, 2009, 2011, 2012, 2017 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" + + +/* Computes a binary quotient of size qn = un - dn. + Output: + + Q = -U * D^{-1} mod B^qn, + + R = (U + Q * D) * B^(-qn) + + Stores the dn least significant limbs of R at {up + un - dn, dn}, + and returns the carry from the addition N + Q*D. + + D must be odd. dinv is (-D)^-1 mod B. */ + +mp_limb_t +mpn_sbpi1_bdiv_qr (mp_ptr qp, + mp_ptr up, mp_size_t un, + mp_srcptr dp, mp_size_t dn, mp_limb_t dinv) +{ + mp_size_t i; + mp_limb_t cy; + + ASSERT (dn > 0); + ASSERT (un > dn); + ASSERT ((dp[0] & 1) != 0); + ASSERT (-(dp[0] * dinv) == 1); + ASSERT (up == qp || !MPN_OVERLAP_P (up, un, qp, un - dn)); + + for (i = un - dn, cy = 0; i != 0; i--) + { + mp_limb_t q = dinv * up[0]; + mp_limb_t hi = mpn_addmul_1 (up, dp, dn, q); + *qp++ = q; + + hi += cy; + cy = hi < cy; + hi += up[dn]; + cy += hi < up[dn]; + up[dn] = hi; + up++; + } + + return cy; +} -- cgit v1.2.3