ui_sub.c revision 1.1.1.3
1 1.1 mrg /* mpz_ui_sub -- Subtract an unsigned one-word integer and an mpz_t. 2 1.1 mrg 3 1.1.1.3 mrg Copyright 2002, 2004, 2015 Free Software Foundation, Inc. 4 1.1 mrg 5 1.1 mrg This file is part of the GNU MP Library. 6 1.1 mrg 7 1.1 mrg The GNU MP Library is free software; you can redistribute it and/or modify 8 1.1.1.2 mrg it under the terms of either: 9 1.1.1.2 mrg 10 1.1.1.2 mrg * the GNU Lesser General Public License as published by the Free 11 1.1.1.2 mrg Software Foundation; either version 3 of the License, or (at your 12 1.1.1.2 mrg option) any later version. 13 1.1.1.2 mrg 14 1.1.1.2 mrg or 15 1.1.1.2 mrg 16 1.1.1.2 mrg * the GNU General Public License as published by the Free Software 17 1.1.1.2 mrg Foundation; either version 2 of the License, or (at your option) any 18 1.1.1.2 mrg later version. 19 1.1.1.2 mrg 20 1.1.1.2 mrg or both in parallel, as here. 21 1.1 mrg 22 1.1 mrg The GNU MP Library is distributed in the hope that it will be useful, but 23 1.1 mrg WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 24 1.1.1.2 mrg or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 25 1.1.1.2 mrg for more details. 26 1.1 mrg 27 1.1.1.2 mrg You should have received copies of the GNU General Public License and the 28 1.1.1.2 mrg GNU Lesser General Public License along with the GNU MP Library. If not, 29 1.1.1.2 mrg see https://www.gnu.org/licenses/. */ 30 1.1 mrg 31 1.1 mrg #include "gmp-impl.h" 32 1.1 mrg 33 1.1 mrg void 34 1.1 mrg mpz_ui_sub (mpz_ptr w, unsigned long int uval, mpz_srcptr v) 35 1.1 mrg { 36 1.1 mrg mp_ptr vp, wp; 37 1.1 mrg mp_size_t vn, wn; 38 1.1 mrg mp_limb_t cy; 39 1.1 mrg 40 1.1 mrg #if BITS_PER_ULONG > GMP_NUMB_BITS /* avoid warnings about shift amount */ 41 1.1 mrg if (uval > GMP_NUMB_MAX) 42 1.1 mrg { 43 1.1 mrg mpz_t u; 44 1.1 mrg mp_limb_t ul[2]; 45 1.1 mrg PTR(u) = ul; 46 1.1 mrg ul[0] = uval & GMP_NUMB_MASK; 47 1.1 mrg ul[1] = uval >> GMP_NUMB_BITS; 48 1.1 mrg SIZ(u) = 2; 49 1.1 mrg mpz_sub (w, u, v); 50 1.1 mrg return; 51 1.1 mrg } 52 1.1 mrg #endif 53 1.1 mrg 54 1.1 mrg vn = SIZ(v); 55 1.1 mrg 56 1.1 mrg if (vn > 1) 57 1.1 mrg { 58 1.1 mrg wp = MPZ_REALLOC (w, vn); 59 1.1 mrg vp = PTR(v); 60 1.1 mrg mpn_sub_1 (wp, vp, vn, (mp_limb_t) uval); 61 1.1 mrg wn = -(vn - (wp[vn - 1] == 0)); 62 1.1 mrg } 63 1.1.1.3 mrg else if (vn >= 0) 64 1.1 mrg { 65 1.1.1.3 mrg mp_limb_t vp0; 66 1.1.1.3 mrg vp0 = PTR (v)[0] & - (mp_limb_t) vn; 67 1.1.1.3 mrg wp = MPZ_NEWALLOC (w, 1); 68 1.1.1.3 mrg if (uval >= vp0) 69 1.1 mrg { 70 1.1.1.3 mrg wp[0] = uval - vp0; 71 1.1 mrg wn = wp[0] != 0; 72 1.1 mrg } 73 1.1 mrg else 74 1.1 mrg { 75 1.1.1.3 mrg wp[0] = vp0 - uval; 76 1.1 mrg wn = -1; 77 1.1 mrg } 78 1.1 mrg } 79 1.1 mrg else /* (vn < 0) */ 80 1.1 mrg { 81 1.1 mrg vn = -vn; 82 1.1 mrg wp = MPZ_REALLOC (w, vn + 1); 83 1.1 mrg vp = PTR(v); 84 1.1 mrg cy = mpn_add_1 (wp, vp, vn, (mp_limb_t) uval); 85 1.1 mrg wp[vn] = cy; 86 1.1 mrg wn = vn + (cy != 0); 87 1.1 mrg } 88 1.1 mrg 89 1.1 mrg SIZ(w) = wn; 90 1.1 mrg } 91
Indexes created Sat Aug 01 00:24:56 UTC 2026