| /* mpn_divrem -- Divide natural numbers, producing both remainder and |
| quotient. This is now just a middle layer for calling the new |
| internal mpn_tdiv_qr. |
| |
| Copyright 1993, 1994, 1995, 1996, 1997, 1999, 2000, 2001, 2002, 2005 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" |
| #include "longlong.h" |
| |
| mp_limb_t |
| mpn_divrem (mp_ptr qp, mp_size_t qxn, |
| mp_ptr np, mp_size_t nn, |
| mp_srcptr dp, mp_size_t dn) |
| { |
| ASSERT (qxn >= 0); |
| ASSERT (nn >= dn); |
| ASSERT (dn >= 1); |
| ASSERT (dp[dn-1] & GMP_NUMB_HIGHBIT); |
| ASSERT (! MPN_OVERLAP_P (np, nn, dp, dn)); |
| ASSERT (! MPN_OVERLAP_P (qp, nn-dn+qxn, np, nn) || qp==np+dn+qxn); |
| ASSERT (! MPN_OVERLAP_P (qp, nn-dn+qxn, dp, dn)); |
| ASSERT_MPN (np, nn); |
| ASSERT_MPN (dp, dn); |
| |
| if (dn == 1) |
| { |
| mp_limb_t ret; |
| mp_ptr q2p; |
| mp_size_t qn; |
| TMP_DECL; |
| |
| TMP_MARK; |
| q2p = (mp_ptr) TMP_ALLOC ((nn + qxn) * BYTES_PER_MP_LIMB); |
| |
| np[0] = mpn_divrem_1 (q2p, qxn, np, nn, dp[0]); |
| qn = nn + qxn - 1; |
| MPN_COPY (qp, q2p, qn); |
| ret = q2p[qn]; |
| |
| TMP_FREE; |
| return ret; |
| } |
| else if (dn == 2) |
| { |
| return mpn_divrem_2 (qp, qxn, np, nn, dp); |
| } |
| else |
| { |
| mp_ptr rp, q2p; |
| mp_limb_t qhl; |
| mp_size_t qn; |
| TMP_DECL; |
| |
| TMP_MARK; |
| if (UNLIKELY (qxn != 0)) |
| { |
| mp_ptr n2p; |
| n2p = (mp_ptr) TMP_ALLOC ((nn + qxn) * BYTES_PER_MP_LIMB); |
| MPN_ZERO (n2p, qxn); |
| MPN_COPY (n2p + qxn, np, nn); |
| q2p = (mp_ptr) TMP_ALLOC ((nn - dn + qxn + 1) * BYTES_PER_MP_LIMB); |
| rp = (mp_ptr) TMP_ALLOC (dn * BYTES_PER_MP_LIMB); |
| mpn_tdiv_qr (q2p, rp, 0L, n2p, nn + qxn, dp, dn); |
| MPN_COPY (np, rp, dn); |
| qn = nn - dn + qxn; |
| MPN_COPY (qp, q2p, qn); |
| qhl = q2p[qn]; |
| } |
| else |
| { |
| q2p = (mp_ptr) TMP_ALLOC ((nn - dn + 1) * BYTES_PER_MP_LIMB); |
| rp = (mp_ptr) TMP_ALLOC (dn * BYTES_PER_MP_LIMB); |
| mpn_tdiv_qr (q2p, rp, 0L, np, nn, dp, dn); |
| MPN_COPY (np, rp, dn); /* overwrite np area with remainder */ |
| qn = nn - dn; |
| MPN_COPY (qp, q2p, qn); |
| qhl = q2p[qn]; |
| } |
| TMP_FREE; |
| return qhl; |
| } |
| } |