nussbaumer_mul.c
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- /* mpn_nussbaumer_mul -- Multiply {ap,an} and {bp,bn} using
- Nussbaumer's negacyclic convolution.
- Contributed to the GNU project by Marco Bodrato.
- THE FUNCTION IN THIS FILE IS INTERNAL WITH A MUTABLE INTERFACE. IT IS ONLY
- SAFE TO REACH IT THROUGH DOCUMENTED INTERFACES. IN FACT, IT IS ALMOST
- GUARANTEED THAT IT WILL CHANGE OR DISAPPEAR IN A FUTURE GNU MP RELEASE.
- Copyright 2009 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 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.
- 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 Lesser General Public
- License for more details.
- You should have received a copy of the GNU Lesser General Public License
- along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
- #include "gmp.h"
- #include "gmp-impl.h"
- /* Multiply {ap,an} by {bp,bn}, and put the result in {pp, an+bn} */
- void
- mpn_nussbaumer_mul (mp_ptr pp,
- mp_srcptr ap, mp_size_t an,
- mp_srcptr bp, mp_size_t bn)
- {
- mp_size_t rn;
- mp_ptr tp;
- TMP_DECL;
- ASSERT (an >= bn);
- ASSERT (bn > 0);
- TMP_MARK;
- if ((ap == bp) && (an == bn))
- {
- rn = mpn_sqrmod_bnm1_next_size (2*an);
- tp = TMP_ALLOC_LIMBS (mpn_sqrmod_bnm1_itch (rn, an));
- mpn_sqrmod_bnm1 (pp, rn, ap, an, tp);
- }
- else
- {
- rn = mpn_mulmod_bnm1_next_size (an + bn);
- tp = TMP_ALLOC_LIMBS (mpn_mulmod_bnm1_itch (rn, an, bn));
- mpn_mulmod_bnm1 (pp, rn, ap, an, bp, bn, tp);
- }
- TMP_FREE;
- }