99 lines
2.7 KiB
C
99 lines
2.7 KiB
C
/* mpn_redc_2. Set cp[] <- up[]/R^n mod mp[]. Clobber up[].
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mp[] is n limbs; up[] is 2n limbs.
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THIS IS AN INTERNAL FUNCTION WITH A MUTABLE INTERFACE. IT IS ONLY
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SAFE TO REACH THIS FUNCTION THROUGH DOCUMENTED INTERFACES.
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Copyright (C) 2000, 2001, 2002, 2004, 2008 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 the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 3 of the License, or (at your
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option) any later version.
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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 Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
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#include "mpir.h"
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#include "gmp-impl.h"
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#include "longlong.h"
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#if GMP_NAIL_BITS != 0
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#error not supported
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#endif
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/* For testing purposes, define our own mpn_addmul_2 if there is none already
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available. */
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#ifndef HAVE_NATIVE_mpn_addmul_2
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mp_limb_t
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mpn_addmul_2 (mp_ptr rp, mp_srcptr up, mp_size_t n, mp_srcptr vp)
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{
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rp[n] = mpn_addmul_1 (rp, up, n, vp[0]);
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return mpn_addmul_1 (rp + 1, up, n, vp[1]);
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}
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#endif
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#if defined (__GNUC__) && defined (__ia64) && W_TYPE_SIZE == 64
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#define umul2low(ph, pl, uh, ul, vh, vl) \
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do { \
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mp_limb_t _ph, _pl; \
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__asm__ ("xma.hu %0 = %3, %5, f0\n\t" \
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"xma.l %1 = %3, %5, f0\n\t" \
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";;\n\t" \
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"xma.l %0 = %3, %4, %0\n\t" \
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";;\n\t" \
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"xma.l %0 = %2, %5, %0" \
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: "=&f" (ph), "=&f" (pl) \
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: "f" (uh), "f" (ul), "f" (vh), "f" (vl)); \
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} while (0)
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#endif
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#ifndef umul2low
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#define umul2low(ph, pl, uh, ul, vh, vl) \
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do { \
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mp_limb_t _ph, _pl; \
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umul_ppmm (_ph, _pl, ul, vl); \
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(ph) = _ph + (ul) * (vh) + (uh) * (vl); \
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(pl) = _pl; \
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} while (0)
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#endif
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void
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mpn_redc_2 (mp_ptr rp, mp_ptr up, mp_srcptr mp, mp_size_t n, mp_srcptr mip)
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{
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mp_limb_t q[2];
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mp_size_t j;
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mp_limb_t upn;
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mp_limb_t cy;
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ASSERT (n > 0);
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ASSERT_MPN (up, 2*n);
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if ((n & 1) != 0)
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{
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up[0] = mpn_addmul_1 (up, mp, n, (up[0] * mip[0]) & GMP_NUMB_MASK);
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up++;
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}
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for (j = n - 2; j >= 0; j -= 2)
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{
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umul2low (q[1], q[0], mip[1], mip[0], up[1], up[0]);
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upn = up[n]; /* mpn_addmul_2 overwrites this */
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up[1] = mpn_addmul_2 (up, mp, n, q);
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up[0] = up[n];
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up[n] = upn;
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up += 2;
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}
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cy = mpn_add_n (rp, up, up - n, n);
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if (cy != 0)
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mpn_sub_n (rp, rp, mp, n);
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}
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