1 /* mpf_ui_div -- Divide an unsigned integer with a float. 2 3 Copyright 1993, 1994, 1995, 1996, 2000, 2001, 2002, 2004, 2005 Free Software 4 Foundation, Inc. 5 6 This file is part of the GNU MP Library. 7 8 The GNU MP Library is free software; you can redistribute it and/or modify 9 it under the terms of the GNU Lesser General Public License as published by 10 the Free Software Foundation; either version 3 of the License, or (at your 11 option) any later version. 12 13 The GNU MP Library is distributed in the hope that it will be useful, but 14 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 15 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 16 License for more details. 17 18 You should have received a copy of the GNU Lesser General Public License 19 along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */ 20 21 #include <stdio.h> /* for NULL */ 22 #include "gmp.h" 23 #include "gmp-impl.h" 24 #include "longlong.h" 25 26 27 void 28 mpf_ui_div (mpf_ptr r, unsigned long int u, mpf_srcptr v) 29 { 30 mp_srcptr vp; 31 mp_ptr rp, tp, remp, new_vp; 32 mp_size_t vsize; 33 mp_size_t rsize, prospective_rsize, zeros, tsize, high_zero; 34 mp_size_t sign_quotient; 35 mp_size_t prec; 36 mp_exp_t rexp; 37 TMP_DECL; 38 39 vsize = v->_mp_size; 40 sign_quotient = vsize; 41 vsize = ABS (vsize); 42 prec = r->_mp_prec; 43 44 if (UNLIKELY (vsize == 0)) 45 DIVIDE_BY_ZERO; 46 47 if (UNLIKELY (u == 0)) 48 { 49 r->_mp_size = 0; 50 r->_mp_exp = 0; 51 return; 52 } 53 54 TMP_MARK; 55 rexp = 1 - v->_mp_exp + 1; 56 57 rp = r->_mp_d; 58 vp = v->_mp_d; 59 60 prospective_rsize = 1 - vsize + 1; /* quot from using given u,v sizes */ 61 rsize = prec + 1; /* desired quot size */ 62 63 zeros = rsize - prospective_rsize; /* padding u to give rsize */ 64 tsize = 1 + zeros; /* u with zeros */ 65 66 if (WANT_TMP_DEBUG) 67 { 68 /* separate alloc blocks, for malloc debugging */ 69 remp = TMP_ALLOC_LIMBS (vsize); 70 tp = TMP_ALLOC_LIMBS (tsize); 71 new_vp = NULL; 72 if (rp == vp) 73 new_vp = TMP_ALLOC_LIMBS (vsize); 74 } 75 else 76 { 77 /* one alloc with calculated size, for efficiency */ 78 mp_size_t size = vsize + tsize + (rp == vp ? vsize : 0); 79 remp = TMP_ALLOC_LIMBS (size); 80 tp = remp + vsize; 81 new_vp = tp + tsize; 82 } 83 84 /* ensure divisor doesn't overlap quotient */ 85 if (rp == vp) 86 { 87 MPN_COPY (new_vp, vp, vsize); 88 vp = new_vp; 89 } 90 91 MPN_ZERO (tp, tsize-1); 92 93 tp[tsize - 1] = u & GMP_NUMB_MASK; 94 #if BITS_PER_ULONG > GMP_NUMB_BITS 95 if (u > GMP_NUMB_MAX) 96 { 97 /* tsize-vsize+1 == rsize, so tsize >= rsize. rsize == prec+1 >= 2, 98 so tsize >= 2, hence there's room for 2-limb u with nails */ 99 ASSERT (tsize >= 2); 100 tp[tsize - 1] = u >> GMP_NUMB_BITS; 101 tp[tsize - 2] = u & GMP_NUMB_MASK; 102 rexp++; 103 } 104 #endif 105 106 ASSERT (tsize-vsize+1 == rsize); 107 mpn_tdiv_qr (rp, remp, (mp_size_t) 0, tp, tsize, vp, vsize); 108 109 /* strip possible zero high limb */ 110 high_zero = (rp[rsize-1] == 0); 111 rsize -= high_zero; 112 rexp -= high_zero; 113 114 r->_mp_size = sign_quotient >= 0 ? rsize : -rsize; 115 r->_mp_exp = rexp; 116 TMP_FREE; 117 } 118