1 /* Test for sqrmod_bnm1 function. 2 3 Contributed to the GNU project by Marco Bodrato. 4 5 Copyright 2009 Free Software Foundation, Inc. 6 7 This file is part of the GNU MP Library test suite. 8 9 The GNU MP Library test suite is free software; you can redistribute it 10 and/or modify it under the terms of the GNU General Public License as 11 published by the Free Software Foundation; either version 3 of the License, 12 or (at your option) any later version. 13 14 The GNU MP Library test suite is distributed in the hope that it will be 15 useful, but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General 17 Public License for more details. 18 19 You should have received a copy of the GNU General Public License along with 20 the GNU MP Library test suite. If not, see https://www.gnu.org/licenses/. */ 21 22 23 #include <stdlib.h> 24 #include <stdio.h> 25 26 #include "gmp-impl.h" 27 #include "tests.h" 28 29 /* Sizes are up to 2^SIZE_LOG limbs */ 30 #ifndef SIZE_LOG 31 #define SIZE_LOG 12 32 #endif 33 34 #ifndef COUNT 35 #define COUNT 3000 36 #endif 37 38 #define MAX_N (1L << SIZE_LOG) 39 #define MIN_N 1 40 41 /* 42 Reference function for squaring modulo B^rn-1. 43 44 The result is expected to be ZERO if and only if one of the operand 45 already is. Otherwise the class [0] Mod(B^rn-1) is represented by 46 B^rn-1. This should not be a problem if sqrmod_bnm1 is used to 47 combine results and obtain a natural number when one knows in 48 advance that the final value is less than (B^rn-1). 49 */ 50 51 static void 52 ref_sqrmod_bnm1 (mp_ptr rp, mp_size_t rn, mp_srcptr ap, mp_size_t an) 53 { 54 mp_limb_t cy; 55 56 ASSERT (0 < an && an <= rn); 57 58 refmpn_mul (rp, ap, an, ap, an); 59 an *= 2; 60 if (an > rn) { 61 cy = mpn_add (rp, rp, rn, rp + rn, an - rn); 62 /* If cy == 1, then the value of rp is at most B^rn - 2, so there can 63 * be no overflow when adding in the carry. */ 64 MPN_INCR_U (rp, rn, cy); 65 } 66 } 67 68 /* 69 Compare the result of the mpn_sqrmod_bnm1 function in the library 70 with the reference function above. 71 */ 72 73 int 74 main (int argc, char **argv) 75 { 76 mp_ptr ap, refp, pp, scratch; 77 int count = COUNT; 78 int test; 79 gmp_randstate_ptr rands; 80 TMP_DECL; 81 TMP_MARK; 82 83 TESTS_REPS (count, argv, argc); 84 85 tests_start (); 86 rands = RANDS; 87 88 ASSERT_ALWAYS (mpn_sqrmod_bnm1_next_size (MAX_N) == MAX_N); 89 90 ap = TMP_ALLOC_LIMBS (MAX_N); 91 refp = TMP_ALLOC_LIMBS (MAX_N * 4); 92 pp = 1+TMP_ALLOC_LIMBS (MAX_N + 2); 93 scratch 94 = 1+TMP_ALLOC_LIMBS (mpn_sqrmod_bnm1_itch (MAX_N, MAX_N) + 2); 95 96 for (test = 0; test < count; test++) 97 { 98 unsigned size_min; 99 unsigned size_range; 100 mp_size_t an,rn,n; 101 mp_size_t itch; 102 mp_limb_t p_before, p_after, s_before, s_after; 103 104 for (size_min = 1; (1L << size_min) < MIN_N; size_min++) 105 ; 106 107 /* We generate an in the MIN_N <= n <= (1 << size_range). */ 108 size_range = size_min 109 + gmp_urandomm_ui (rands, SIZE_LOG + 1 - size_min); 110 111 n = MIN_N 112 + gmp_urandomm_ui (rands, (1L << size_range) + 1 - MIN_N); 113 n = mpn_sqrmod_bnm1_next_size (n); 114 115 if (n == 1) 116 an = 1; 117 else 118 an = ((n+1) >> 1) + gmp_urandomm_ui (rands, (n+1) >> 1); 119 120 mpn_random2 (ap, an); 121 122 /* Sometime trigger the borderline conditions 123 A = -1,0,+1 Mod(B^{n/2}+1). 124 This only makes sense if there is at least a split, i.e. n is even. */ 125 if ((test & 0x1f) == 1 && (n & 1) == 0) { 126 mp_size_t x; 127 MPN_COPY (ap, ap + (n >> 1), an - (n >> 1)); 128 MPN_ZERO (ap + an - (n >> 1) , n - an); 129 x = (n == an) ? 0 : gmp_urandomm_ui (rands, n - an); 130 ap[x] += gmp_urandomm_ui (rands, 3) - 1; 131 } 132 rn = MIN(n, 2*an); 133 mpn_random2 (pp-1, rn + 2); 134 p_before = pp[-1]; 135 p_after = pp[rn]; 136 137 itch = mpn_sqrmod_bnm1_itch (n, an); 138 ASSERT_ALWAYS (itch <= mpn_sqrmod_bnm1_itch (MAX_N, MAX_N)); 139 mpn_random2 (scratch-1, itch+2); 140 s_before = scratch[-1]; 141 s_after = scratch[itch]; 142 143 mpn_sqrmod_bnm1 ( pp, n, ap, an, scratch); 144 ref_sqrmod_bnm1 (refp, n, ap, an); 145 if (pp[-1] != p_before || pp[rn] != p_after 146 || scratch[-1] != s_before || scratch[itch] != s_after 147 || mpn_cmp (refp, pp, rn) != 0) 148 { 149 printf ("ERROR in test %d, an = %d, n = %d\n", 150 test, (int) an, (int) n); 151 if (pp[-1] != p_before) 152 { 153 printf ("before pp:"); mpn_dump (pp -1, 1); 154 printf ("keep: "); mpn_dump (&p_before, 1); 155 } 156 if (pp[rn] != p_after) 157 { 158 printf ("after pp:"); mpn_dump (pp + rn, 1); 159 printf ("keep: "); mpn_dump (&p_after, 1); 160 } 161 if (scratch[-1] != s_before) 162 { 163 printf ("before scratch:"); mpn_dump (scratch-1, 1); 164 printf ("keep: "); mpn_dump (&s_before, 1); 165 } 166 if (scratch[itch] != s_after) 167 { 168 printf ("after scratch:"); mpn_dump (scratch + itch, 1); 169 printf ("keep: "); mpn_dump (&s_after, 1); 170 } 171 mpn_dump (ap, an); 172 mpn_dump (pp, rn); 173 mpn_dump (refp, rn); 174 175 abort(); 176 } 177 } 178 TMP_FREE; 179 tests_end (); 180 return 0; 181 } 182