1 /* mpz_mul -- Multiply two integers. 2 3 Copyright 1991, 1993, 1994, 1996, 2000, 2001, 2005, 2009, 2011, 2012, 4 2015 Free Software 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 either: 10 11 * the GNU Lesser General Public License as published by the Free 12 Software Foundation; either version 3 of the License, or (at your 13 option) any later version. 14 15 or 16 17 * the GNU General Public License as published by the Free Software 18 Foundation; either version 2 of the License, or (at your option) any 19 later version. 20 21 or both in parallel, as here. 22 23 The GNU MP Library is distributed in the hope that it will be useful, but 24 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 25 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 26 for more details. 27 28 You should have received copies of the GNU General Public License and the 29 GNU Lesser General Public License along with the GNU MP Library. If not, 30 see https://www.gnu.org/licenses/. */ 31 32 #include <stdio.h> /* for NULL */ 33 #include "gmp-impl.h" 34 35 36 void 37 mpz_mul (mpz_ptr w, mpz_srcptr u, mpz_srcptr v) 38 { 39 mp_size_t usize; 40 mp_size_t vsize; 41 mp_size_t wsize; 42 mp_size_t sign_product; 43 mp_ptr up, vp; 44 mp_ptr wp; 45 mp_ptr free_me; 46 size_t free_me_size; 47 mp_limb_t cy_limb; 48 TMP_DECL; 49 50 usize = SIZ (u); 51 vsize = SIZ (v); 52 sign_product = usize ^ vsize; 53 usize = ABS (usize); 54 vsize = ABS (vsize); 55 56 if (usize < vsize) 57 { 58 MPZ_SRCPTR_SWAP (u, v); 59 MP_SIZE_T_SWAP (usize, vsize); 60 } 61 62 if (vsize == 0) 63 { 64 SIZ (w) = 0; 65 return; 66 } 67 68 #if HAVE_NATIVE_mpn_mul_2 69 if (vsize <= 2) 70 { 71 wp = MPZ_REALLOC (w, usize+vsize); 72 if (vsize == 1) 73 cy_limb = mpn_mul_1 (wp, PTR (u), usize, PTR (v)[0]); 74 else 75 { 76 cy_limb = mpn_mul_2 (wp, PTR (u), usize, PTR (v)); 77 usize++; 78 } 79 wp[usize] = cy_limb; 80 usize += (cy_limb != 0); 81 SIZ (w) = (sign_product >= 0 ? usize : -usize); 82 return; 83 } 84 #else 85 if (vsize == 1) 86 { 87 wp = MPZ_REALLOC (w, usize+1); 88 cy_limb = mpn_mul_1 (wp, PTR (u), usize, PTR (v)[0]); 89 wp[usize] = cy_limb; 90 usize += (cy_limb != 0); 91 SIZ (w) = (sign_product >= 0 ? usize : -usize); 92 return; 93 } 94 #endif 95 96 TMP_MARK; 97 free_me = NULL; 98 up = PTR (u); 99 vp = PTR (v); 100 wp = PTR (w); 101 102 /* Ensure W has space enough to store the result. */ 103 wsize = usize + vsize; 104 if (ALLOC (w) < wsize) 105 { 106 if (ALLOC (w) != 0) 107 { 108 if (wp == up || wp == vp) 109 { 110 free_me = wp; 111 free_me_size = ALLOC (w); 112 } 113 else 114 (*__gmp_free_func) (wp, (size_t) ALLOC (w) * GMP_LIMB_BYTES); 115 } 116 117 ALLOC (w) = wsize; 118 wp = __GMP_ALLOCATE_FUNC_LIMBS (wsize); 119 PTR (w) = wp; 120 } 121 else 122 { 123 /* Make U and V not overlap with W. */ 124 if (wp == up) 125 { 126 /* W and U are identical. Allocate temporary space for U. */ 127 up = TMP_ALLOC_LIMBS (usize); 128 /* Is V identical too? Keep it identical with U. */ 129 if (wp == vp) 130 vp = up; 131 /* Copy to the temporary space. */ 132 MPN_COPY (up, wp, usize); 133 } 134 else if (wp == vp) 135 { 136 /* W and V are identical. Allocate temporary space for V. */ 137 vp = TMP_ALLOC_LIMBS (vsize); 138 /* Copy to the temporary space. */ 139 MPN_COPY (vp, wp, vsize); 140 } 141 } 142 143 if (up == vp) 144 { 145 mpn_sqr (wp, up, usize); 146 cy_limb = wp[wsize - 1]; 147 } 148 else 149 { 150 cy_limb = mpn_mul (wp, up, usize, vp, vsize); 151 } 152 153 wsize -= cy_limb == 0; 154 155 SIZ (w) = sign_product < 0 ? -wsize : wsize; 156 if (free_me != NULL) 157 (*__gmp_free_func) (free_me, free_me_size * GMP_LIMB_BYTES); 158 TMP_FREE; 159 } 160