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/*
Copyright (C) 2009 William Hart
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 "ulong_extras.h"
ulong
n_powmod_ui_precomp(ulong a, ulong exp, ulong n, double npre)
{
ulong x, y;
if (n == UWORD(1))
return WORD(0);
x = UWORD(1);
y = a;
while (exp)
{
if (exp & WORD(1))
x = n_mulmod_precomp(x, y, n, npre);
exp >>= 1;
if (exp)
y = n_mulmod_precomp(y, y, n, npre);
}
return x;
}
ulong
n_powmod_precomp(ulong a, slong exp, ulong n, double npre)
{
if (exp < 0)
{
a = n_invmod(a, n);
exp = -(ulong) exp;
}
return n_powmod_ui_precomp(a, exp, n, npre);
}