155 lines
4.5 KiB
C
155 lines
4.5 KiB
C
/* Implementation of the squaring algorithm with Toom-Cook 8.5-way.
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Contributed to the GNU project by Marco Bodrato.
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THE FUNCTION IN THIS FILE IS INTERNAL WITH A MUTABLE INTERFACE. IT IS ONLY
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SAFE TO REACH IT THROUGH DOCUMENTED INTERFACES. IN FACT, IT IS ALMOST
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GUARANTEED THAT IT WILL CHANGE OR DISAPPEAR IN A FUTURE GNU MP RELEASE.
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Copyright 2009 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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#if GMP_NUMB_BITS < 29
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#error Not implemented.
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#endif
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#if GMP_NUMB_BITS < 43
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#define BIT_CORRECTION 1
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#define CORRECTION_BITS GMP_NUMB_BITS
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#else
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#define BIT_CORRECTION 0
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#define CORRECTION_BITS 0
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#endif
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#ifndef SQR_TOOM8_THRESHOLD
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#define SQR_TOOM8_THRESHOLD MUL_TOOM8H_THRESHOLD
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#endif
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#define TOOM8_SQR_REC(p, a, n) \
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do { \
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if (BELOW_THRESHOLD (n, SQR_TOOM8_THRESHOLD)) \
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mpn_sqr (p, a, n); \
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else \
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mpn_toom8_sqr_n (p, a, n); \
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} while (0)
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void
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mpn_toom8_sqr_n (mp_ptr pp, mp_srcptr ap, mp_size_t an)
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{
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mp_size_t n, s;
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mp_ptr scratch;
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TMP_DECL;
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TMP_MARK;
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/***************************** decomposition *******************************/
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ASSERT ( an >= 40 );
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n = 1 + ((an - 1)>>3);
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s = an - 7 * n;
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ASSERT (0 < s && s <= n);
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ASSERT ( s + s > 3 );
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scratch = TMP_ALLOC_LIMBS (30 * n + 6);
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#define r6 (pp + 3 * n) /* 3n+1 */
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#define r4 (pp + 7 * n) /* 3n+1 */
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#define r2 (pp +11 * n) /* 3n+1 */
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#define r0 (pp +15 * n) /* s+t <= 2*n */
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#define r7 (scratch) /* 3n+1 */
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#define r5 (scratch + 3 * n + 1) /* 3n+1 */
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#define r3 (scratch + 6 * n + 2) /* 3n+1 */
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#define r1 (scratch + 9 * n + 3) /* 3n+1 */
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#define v0 (pp +11 * n) /* n+1 */
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#define v2 (pp +13 * n+2) /* n+1 */
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#define wse (scratch +12 * n + 4) /* 3n+1 */
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/* Alloc also 3n+1 limbs for ws... toom_interpolate_16pts may
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need all of them, when DO_mpn_sublsh_n use a a scratch */
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/********************** evaluation and recursive calls *********************/
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/* $\pm1/8$ */
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mpn_toom_eval_pm2rexp (v2, v0, 7, ap, n, s, 3, pp);
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TOOM8_SQR_REC(pp, v0, n + 1); /* A(-1/8)*B(-1/8)*8^. */
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TOOM8_SQR_REC(r7, v2, n + 1); /* A(+1/8)*B(+1/8)*8^. */
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mpn_toom_couple_handling (r7, 2 * n + 1 + BIT_CORRECTION, pp, 0, n, 3, 0);
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/* $\pm1/4$ */
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mpn_toom_eval_pm2rexp (v2, v0, 7, ap, n, s, 2, pp);
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TOOM8_SQR_REC(pp, v0, n + 1); /* A(-1/4)*B(-1/4)*4^. */
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TOOM8_SQR_REC(r5, v2, n + 1); /* A(+1/4)*B(+1/4)*4^. */
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mpn_toom_couple_handling (r5, 2 * n + 1, pp, 0, n, 2, 0);
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/* $\pm2$ */
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mpn_toom_eval_pm2 (v2, v0, 7, ap, n, s, pp);
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TOOM8_SQR_REC(pp, v0, n + 1); /* A(-2)*B(-2) */
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TOOM8_SQR_REC(r3, v2, n + 1); /* A(+2)*B(+2) */
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mpn_toom_couple_handling (r3, 2 * n + 1, pp, 0, n, 1, 2);
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/* $\pm8$ */
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mpn_toom_eval_pm2exp (v2, v0, 7, ap, n, s, 3, pp);
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TOOM8_SQR_REC(pp, v0, n + 1); /* A(-8)*B(-8) */
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TOOM8_SQR_REC(r1, v2, n + 1); /* A(+8)*B(+8) */
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mpn_toom_couple_handling (r1, 2 * n + 1 + BIT_CORRECTION, pp, 0, n, 3, 6);
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/* $\pm1/2$ */
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mpn_toom_eval_pm2rexp (v2, v0, 7, ap, n, s, 1, pp);
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TOOM8_SQR_REC(pp, v0, n + 1); /* A(-1/2)*B(-1/2)*2^. */
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TOOM8_SQR_REC(r6, v2, n + 1); /* A(+1/2)*B(+1/2)*2^. */
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mpn_toom_couple_handling (r6, 2 * n + 1, pp, 0, n, 1, 0);
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/* $\pm1$ */
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mpn_toom_eval_pm1 (v2, v0, 7, ap, n, s, pp);
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TOOM8_SQR_REC(pp, v0, n + 1); /* A(-1)*B(-1) */
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TOOM8_SQR_REC(r4, v2, n + 1); /* A(1)*B(1) */
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mpn_toom_couple_handling (r4, 2 * n + 1, pp, 0, n, 0, 0);
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/* $\pm4$ */
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mpn_toom_eval_pm2exp (v2, v0, 7, ap, n, s, 2, pp);
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TOOM8_SQR_REC(pp, v0, n + 1); /* A(-4)*B(-4) */
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TOOM8_SQR_REC(r2, v2, n + 1); /* A(+4)*B(+4) */
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mpn_toom_couple_handling (r2, 2 * n + 1, pp, 0, n, 2, 4);
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#undef v0
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#undef v2
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/* A(0)*B(0) */
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TOOM8_SQR_REC(pp, ap, n);
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mpn_toom_interpolate_16pts (pp, r1, r3, r5, r7, n, 2 * s, 0, wse);
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TMP_FREE;
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#undef r0
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#undef r1
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#undef r2
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#undef r3
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#undef r4
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#undef r5
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#undef r6
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#undef wse
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}
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