1 /* mpz_mul -- Multiply two integers. 2 3 Copyright 1991, 1993, 1994, 1996, 2000, 2001, 2005 Free Software Foundation, 4 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 #ifdef BERKELEY_MP 25 #include "mp.h" 26 #endif 27 28 29 void 30 #ifndef BERKELEY_MP 31 mpz_mul (mpz_ptr w, mpz_srcptr u, mpz_srcptr v) 32 #else /* BERKELEY_MP */ 33 mult (mpz_srcptr u, mpz_srcptr v, mpz_ptr w) 34 #endif /* BERKELEY_MP */ 35 { 36 mp_size_t usize = u->_mp_size; 37 mp_size_t vsize = v->_mp_size; 38 mp_size_t wsize; 39 mp_size_t sign_product; 40 mp_ptr up, vp; 41 mp_ptr wp; 42 mp_ptr free_me; 43 size_t free_me_size; 44 mp_limb_t cy_limb; 45 TMP_DECL; 46 47 sign_product = usize ^ vsize; 48 usize = ABS (usize); 49 vsize = ABS (vsize); 50 51 if (usize < vsize) 52 { 53 MPZ_SRCPTR_SWAP (u, v); 54 MP_SIZE_T_SWAP (usize, vsize); 55 } 56 57 if (vsize == 0) 58 { 59 SIZ(w) = 0; 60 return; 61 } 62 63 #if HAVE_NATIVE_mpn_mul_2 64 if (vsize <= 2) 65 { 66 MPZ_REALLOC (w, usize+vsize); 67 wp = PTR(w); 68 if (vsize == 1) 69 cy_limb = mpn_mul_1 (wp, PTR(u), usize, PTR(v)[0]); 70 else 71 { 72 cy_limb = mpn_mul_2 (wp, PTR(u), usize, PTR(v)); 73 usize++; 74 } 75 wp[usize] = cy_limb; 76 usize += (cy_limb != 0); 77 SIZ(w) = (sign_product >= 0 ? usize : -usize); 78 return; 79 } 80 #else 81 if (vsize == 1) 82 { 83 MPZ_REALLOC (w, usize+1); 84 wp = PTR(w); 85 cy_limb = mpn_mul_1 (wp, PTR(u), usize, PTR(v)[0]); 86 wp[usize] = cy_limb; 87 usize += (cy_limb != 0); 88 SIZ(w) = (sign_product >= 0 ? usize : -usize); 89 return; 90 } 91 #endif 92 93 TMP_MARK; 94 free_me = NULL; 95 up = u->_mp_d; 96 vp = v->_mp_d; 97 wp = w->_mp_d; 98 99 /* Ensure W has space enough to store the result. */ 100 wsize = usize + vsize; 101 if (w->_mp_alloc < wsize) 102 { 103 if (wp == up || wp == vp) 104 { 105 free_me = wp; 106 free_me_size = w->_mp_alloc; 107 } 108 else 109 (*__gmp_free_func) (wp, w->_mp_alloc * BYTES_PER_MP_LIMB); 110 111 w->_mp_alloc = wsize; 112 wp = (mp_ptr) (*__gmp_allocate_func) (wsize * BYTES_PER_MP_LIMB); 113 w->_mp_d = wp; 114 } 115 else 116 { 117 /* Make U and V not overlap with W. */ 118 if (wp == up) 119 { 120 /* W and U are identical. Allocate temporary space for U. */ 121 up = (mp_ptr) TMP_ALLOC (usize * BYTES_PER_MP_LIMB); 122 /* Is V identical too? Keep it identical with U. */ 123 if (wp == vp) 124 vp = up; 125 /* Copy to the temporary space. */ 126 MPN_COPY (up, wp, usize); 127 } 128 else if (wp == vp) 129 { 130 /* W and V are identical. Allocate temporary space for V. */ 131 vp = (mp_ptr) TMP_ALLOC (vsize * BYTES_PER_MP_LIMB); 132 /* Copy to the temporary space. */ 133 MPN_COPY (vp, wp, vsize); 134 } 135 } 136 137 cy_limb = mpn_mul (wp, up, usize, vp, vsize); 138 wsize = usize + vsize; 139 wsize -= cy_limb == 0; 140 141 w->_mp_size = sign_product < 0 ? -wsize : wsize; 142 if (free_me != NULL) 143 (*__gmp_free_func) (free_me, free_me_size * BYTES_PER_MP_LIMB); 144 TMP_FREE; 145 } 146