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Diffstat (limited to 'Build/source/libs/gmp/gmp-src/mpn/generic/sbpi1_bdiv_r.c')
-rw-r--r-- | Build/source/libs/gmp/gmp-src/mpn/generic/sbpi1_bdiv_r.c | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/Build/source/libs/gmp/gmp-src/mpn/generic/sbpi1_bdiv_r.c b/Build/source/libs/gmp/gmp-src/mpn/generic/sbpi1_bdiv_r.c new file mode 100644 index 00000000000..a609951e4fd --- /dev/null +++ b/Build/source/libs/gmp/gmp-src/mpn/generic/sbpi1_bdiv_r.c @@ -0,0 +1,79 @@ +/* mpn_sbpi1_bdiv_r -- schoolbook Hensel division with precomputed inverse, + returning 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_r (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); + + 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); + + hi += cy; + cy = hi < cy; + hi += up[dn]; + cy += hi < up[dn]; + up[dn] = hi; + up++; + } + + return cy; +} |