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/*
Copyright (C) 2015 William Hart
Copyright (C) 2015 Vladimir Glazachev
Copyright (C) 2024 Vincent Neiger
This file is part of FLINT.
FLINT is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include "test_helpers.h"
#include "ulong_extras.h"
TEST_FUNCTION_START(n_mulmod_shoup, state)
{
int i, result;
for (i = 0; i < 10000 * flint_test_multiplier(); i++)
{
const ulong d = n_randtest_not_zero(state) / 2 + 1; // 0 < d < 2**(FLINT_BITS-1)
const ulong a = n_randtest(state) % d; // a must be < d
const ulong b = n_randtest(state); // b is arbitrary
// mulmod_shoup
const ulong a_pr = n_mulmod_precomp_shoup(a, d);
const ulong r1 = n_mulmod_shoup(a, b, a_pr, d);
// trivial mulmod
ulong r2, q, p1, p2;
umul_ppmm(p1, p2, a, b);
p1 %= d;
udiv_qrnnd(q, r2, p1, p2, d);
result = (r1 == r2);
if (!result)
TEST_FUNCTION_FAIL(
"a = %wu, b = %wu, d = %wu, a_pr = %wu\n"
"q = %wu, r1 = %wu, r2 = %wu\n",
a, b, d, a_pr, q, r1, r2);
}
TEST_FUNCTION_END(state);
}