1/* mpn_div_qr_2n_pi1 2 3 Contributed to the GNU project by Torbjorn Granlund and Niels M��ller 4 5 THIS FILE CONTAINS INTERNAL FUNCTIONS WITH MUTABLE INTERFACES. IT IS ONLY 6 SAFE TO REACH THEM THROUGH DOCUMENTED INTERFACES. IN FACT, IT IS ALMOST 7 GUARANTEED THAT THEY'LL CHANGE OR DISAPPEAR IN A FUTURE GNU MP RELEASE. 8 9 10Copyright 1993-1996, 1999-2002, 2011 Free Software Foundation, Inc. 11 12This file is part of the GNU MP Library. 13 14The GNU MP Library is free software; you can redistribute it and/or modify 15it under the terms of either: 16 17 * the GNU Lesser General Public License as published by the Free 18 Software Foundation; either version 3 of the License, or (at your 19 option) any later version. 20 21or 22 23 * the GNU General Public License as published by the Free Software 24 Foundation; either version 2 of the License, or (at your option) any 25 later version. 26 27or both in parallel, as here. 28 29The GNU MP Library is distributed in the hope that it will be useful, but 30WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 31or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 32for more details. 33 34You should have received copies of the GNU General Public License and the 35GNU Lesser General Public License along with the GNU MP Library. If not, 36see https://www.gnu.org/licenses/. */ 37 38#include "gmp-impl.h" 39#include "longlong.h" 40 41 42/* 3/2 loop, for normalized divisor */ 43mp_limb_t 44mpn_div_qr_2n_pi1 (mp_ptr qp, mp_ptr rp, mp_srcptr np, mp_size_t nn, 45 mp_limb_t d1, mp_limb_t d0, mp_limb_t di) 46{ 47 mp_limb_t qh; 48 mp_size_t i; 49 mp_limb_t r1, r0; 50 51 ASSERT (nn >= 2); 52 ASSERT (d1 & GMP_NUMB_HIGHBIT); 53 54 np += nn - 2; 55 r1 = np[1]; 56 r0 = np[0]; 57 58 qh = 0; 59 if (r1 >= d1 && (r1 > d1 || r0 >= d0)) 60 { 61#if GMP_NAIL_BITS == 0 62 sub_ddmmss (r1, r0, r1, r0, d1, d0); 63#else 64 r0 = r0 - d0; 65 r1 = r1 - d1 - (r0 >> GMP_LIMB_BITS - 1); 66 r0 &= GMP_NUMB_MASK; 67#endif 68 qh = 1; 69 } 70 71 for (i = nn - 2 - 1; i >= 0; i--) 72 { 73 mp_limb_t n0, q; 74 n0 = np[-1]; 75 udiv_qr_3by2 (q, r1, r0, r1, r0, n0, d1, d0, di); 76 np--; 77 qp[i] = q; 78 } 79 80 rp[1] = r1; 81 rp[0] = r0; 82 83 return qh; 84} 85