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ff4ff35918
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.
115 lines
2.9 KiB
C
115 lines
2.9 KiB
C
/* Alpha mpn_divexact_1 -- mpn by limb exact division.
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THE FUNCTIONS IN THIS FILE ARE FOR INTERNAL USE ONLY. THEY'RE ALMOST
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CERTAIN TO BE SUBJECT TO INCOMPATIBLE CHANGES OR DISAPPEAR COMPLETELY IN
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FUTURE GNU MP RELEASES.
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Copyright 2000-2003 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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#include "longlong.h"
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/* cycles/limb
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EV4: 47.0
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EV5: 30.0
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EV6: 15.0
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*/
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/* The dependent chain is as follows (the same as modexact), and this is
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what the code runs as.
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ev4 ev5 ev6
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1 1 1 sub y = x - h
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23 13 7 mulq q = y * inverse
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23 15 7 umulh h = high (q * d)
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-- -- --
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47 30 15
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The time to load src[i+1] and establish x hides under the umulh latency. */
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void
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mpn_divexact_1 (mp_ptr dst, mp_srcptr src, mp_size_t size, mp_limb_t divisor)
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{
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mp_limb_t inverse, lshift_mask, s, sr, s_next, c, h, x, y, q, dummy;
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unsigned rshift, lshift;
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ASSERT (size >= 1);
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ASSERT (divisor != 0);
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ASSERT (MPN_SAME_OR_SEPARATE_P (dst, src, size));
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ASSERT_MPN (src, size);
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ASSERT_LIMB (divisor);
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s_next = *src++; /* src[0] */
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rshift = 0;
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lshift_mask = 0;
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if ((divisor & 1) == 0)
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{
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count_trailing_zeros (rshift, divisor);
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lshift_mask = MP_LIMB_T_MAX;
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divisor >>= rshift;
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}
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binvert_limb (inverse, divisor);
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lshift = 64 - rshift;
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c = 0;
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h = 0;
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sr = s_next >> rshift;
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size--;
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if (LIKELY (size != 0))
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{
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do
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{
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s_next = *src++; /* src[i+1] */
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s = sr | ((s_next << lshift) & lshift_mask);
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x = s - c;
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c = s < c;
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sr = s_next >> rshift;
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y = x - h;
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c += (x < h);
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q = y * inverse;
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*dst++ = q;
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umul_ppmm (h, dummy, q, divisor);
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size--;
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}
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while (size != 0);
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}
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x = sr - c;
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y = x - h;
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q = y * inverse;
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*dst = q; /* dst[size-1] */
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}
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