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facf0c92e0
Red Bear OS is a full fork. All sources must be available from git clone with zero network access. Removed gitignore rules that excluded fetched source trees under recipes/*/source/, local/recipes/kde/*/source/, local/recipes/qt/*/source/, and vendor source trees. Build artifacts (target/, build/, source.tar, *.o, *.so) remain excluded. 127291 files added — kernel, relibc, base, bootloader, pkgar, all KDE/Qt frameworks, mesa, wayland, DRM drivers, and every other recipe source.
107 lines
3.1 KiB
C
107 lines
3.1 KiB
C
/* Compute {up,n}^(-1) mod B^n.
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Contributed to the GNU project by Torbjorn Granlund.
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THE FUNCTIONS IN THIS FILE ARE INTERNAL WITH MUTABLE INTERFACES. IT IS ONLY
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SAFE TO REACH THEM THROUGH DOCUMENTED INTERFACES. IN FACT, IT IS ALMOST
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GUARANTEED THAT THEY WILL CHANGE OR DISAPPEAR IN A FUTURE GMP RELEASE.
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Copyright (C) 2004-2007, 2009, 2012, 2017, 2021 Free Software Foundation, Inc.
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This file is part of the GNU MP Library.
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The GNU MP Library is free software; you can redistribute it and/or modify
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it under the terms of either:
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* the GNU Lesser General Public License as published by the Free
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Software Foundation; either version 3 of the License, or (at your
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option) any later version.
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or
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* the GNU General Public License as published by the Free Software
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Foundation; either version 2 of the License, or (at your option) any
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later version.
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or both in parallel, as here.
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The GNU MP Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received copies of the GNU General Public License and the
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GNU Lesser General Public License along with the GNU MP Library. If not,
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see https://www.gnu.org/licenses/. */
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#include "gmp-impl.h"
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/*
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r[k+1] = r[k] - r[k] * (u*r[k] - 1)
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r[k+1] = r[k] + r[k] - r[k]*(u*r[k])
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*/
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#if TUNE_PROGRAM_BUILD
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#define NPOWS \
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((sizeof(mp_size_t) > 6 ? 48 : 8*sizeof(mp_size_t)))
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#else
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#define NPOWS \
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((sizeof(mp_size_t) > 6 ? 48 : 8*sizeof(mp_size_t)) - LOG2C (BINV_NEWTON_THRESHOLD))
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#endif
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mp_size_t
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mpn_binvert_itch (mp_size_t n)
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{
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mp_size_t itch_local = mpn_mulmod_bnm1_next_size (n);
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mp_size_t itch_out = mpn_mulmod_bnm1_itch (itch_local, n, (n + 1) >> 1);
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return itch_local + itch_out;
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}
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void
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mpn_binvert (mp_ptr rp, mp_srcptr up, mp_size_t n, mp_ptr scratch)
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{
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mp_ptr xp;
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mp_size_t rn, newrn;
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mp_size_t sizes[NPOWS], *sizp;
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mp_limb_t di;
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/* Compute the computation precisions from highest to lowest, leaving the
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base case size in 'rn'. */
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sizp = sizes;
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for (rn = n; ABOVE_THRESHOLD (rn, BINV_NEWTON_THRESHOLD); rn = (rn + 1) >> 1)
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*sizp++ = rn;
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xp = scratch;
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/* Compute a base value of rn limbs. */
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MPN_ZERO (xp, rn);
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xp[0] = 1;
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binvert_limb (di, up[0]);
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if (BELOW_THRESHOLD (rn, DC_BDIV_Q_THRESHOLD))
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mpn_sbpi1_bdiv_q (rp, xp, rn, up, rn, -di);
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else
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mpn_dcpi1_bdiv_q (rp, xp, rn, up, rn, -di);
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mpn_neg (rp, rp, rn);
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/* Use Newton iterations to get the desired precision. */
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for (; rn < n; rn = newrn)
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{
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mp_size_t m;
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newrn = *--sizp;
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/* X <- UR. */
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m = mpn_mulmod_bnm1_next_size (newrn);
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mpn_mulmod_bnm1 (xp, m, up, newrn, rp, rn, xp + m);
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/* Only the values in the range xp + rn .. xp + newrn - 1 are
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used by the _mullo_n below.
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Since m >= newrn, we do not need the following. */
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/* mpn_sub_1 (xp + m, xp, rn - (m - newrn), 1); */
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/* R = R(X/B^rn) */
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mpn_mullo_n (rp + rn, rp, xp + rn, newrn - rn);
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mpn_neg (rp + rn, rp + rn, newrn - rn);
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}
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}
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