1 /* mpz_cdiv_q_ui -- Division rounding the quotient towards +infinity. The 2 remainder gets the opposite sign as the denominator. In order to make it 3 always fit into the return type, the negative of the true remainder is 4 returned. 5 6 Copyright 1994, 1996, 1999, 2001, 2002, 2004 Free Software Foundation, Inc. 7 8 This file is part of the GNU MP Library. 9 10 The GNU MP Library is free software; you can redistribute it and/or modify 11 it under the terms of the GNU Lesser General Public License as published by 12 the Free Software Foundation; either version 3 of the License, or (at your 13 option) any later version. 14 15 The GNU MP Library is distributed in the hope that it will be useful, but 16 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 17 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 18 License for more details. 19 20 You should have received a copy of the GNU Lesser General Public License 21 along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */ 22 23 #include "gmp.h" 24 #include "gmp-impl.h" 25 26 unsigned long int 27 mpz_cdiv_q_ui (mpz_ptr quot, mpz_srcptr dividend, unsigned long int divisor) 28 { 29 mp_size_t ns, nn, qn; 30 mp_ptr np, qp; 31 mp_limb_t rl; 32 33 if (divisor == 0) 34 DIVIDE_BY_ZERO; 35 36 ns = SIZ(dividend); 37 if (ns == 0) 38 { 39 SIZ(quot) = 0; 40 return 0; 41 } 42 43 nn = ABS(ns); 44 MPZ_REALLOC (quot, nn); 45 qp = PTR(quot); 46 np = PTR(dividend); 47 48 #if BITS_PER_ULONG > GMP_NUMB_BITS /* avoid warnings about shift amount */ 49 if (divisor > GMP_NUMB_MAX) 50 { 51 mp_limb_t dp[2], rp[2]; 52 53 if (nn == 1) /* tdiv_qr requirements; tested above for 0 */ 54 { 55 qp[0] = 0; 56 rl = np[0]; 57 qn = 1; /* a white lie, fixed below */ 58 } 59 else 60 { 61 dp[0] = divisor & GMP_NUMB_MASK; 62 dp[1] = divisor >> GMP_NUMB_BITS; 63 mpn_tdiv_qr (qp, rp, (mp_size_t) 0, np, nn, dp, (mp_size_t) 2); 64 rl = rp[0] + (rp[1] << GMP_NUMB_BITS); 65 qn = nn - 2 + 1; 66 } 67 68 if (rl != 0 && ns >= 0) 69 { 70 mpn_incr_u (qp, (mp_limb_t) 1); 71 rl = divisor - rl; 72 } 73 74 qn -= qp[qn - 1] == 0; qn -= qn != 0 && qp[qn - 1] == 0; 75 } 76 else 77 #endif 78 { 79 rl = mpn_divrem_1 (qp, (mp_size_t) 0, np, nn, (mp_limb_t) divisor); 80 81 if (rl != 0 && ns >= 0) 82 { 83 mpn_incr_u (qp, (mp_limb_t) 1); 84 rl = divisor - rl; 85 } 86 87 qn = nn - (qp[nn - 1] == 0); 88 } 89 90 SIZ(quot) = ns >= 0 ? qn : -qn; 91 return rl; 92 } 93