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/* Functions needed for bootstrapping the gmp build, based on mini-gmp.
Copyright 2001, 2002, 2004, 2011, 2012 Free Software Foundation, Inc.
This file is part of the GNU MP Library.
The GNU MP Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 3 of the License, or (at your
option) any later version.
The GNU MP Library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
#include "mini-gmp/mini-gmp.c"
#define MIN(l,o) ((l) < (o) ? (l) : (o))
#define PTR(x) ((x)->_mp_d)
#define SIZ(x) ((x)->_mp_size)
#define xmalloc gmp_default_alloc
int
isprime (unsigned long int t)
{
unsigned long int q, r, d;
if (t < 32)
return (0xa08a28acUL >> t) & 1;
if ((t & 1) == 0)
return 0;
if (t % 3 == 0)
return 0;
if (t % 5 == 0)
return 0;
if (t % 7 == 0)
return 0;
for (d = 11;;)
{
q = t / d;
r = t - q * d;
if (q < d)
return 1;
if (r == 0)
break;
d += 2;
q = t / d;
r = t - q * d;
if (q < d)
return 1;
if (r == 0)
break;
d += 4;
}
return 0;
}
int
log2_ceil (int n)
{
int e;
assert (n >= 1);
for (e = 0; ; e++)
if ((1 << e) >= n)
break;
return e;
}
/* Set inv to the inverse of d, in the style of invert_limb, ie. for
udiv_qrnnd_preinv. */
void
mpz_preinv_invert (mpz_t inv, mpz_t d, int numb_bits)
{
mpz_t t;
int norm;
assert (SIZ(d) > 0);
norm = numb_bits - mpz_sizeinbase (d, 2);
assert (norm >= 0);
mpz_init_set_ui (t, 1L);
mpz_mul_2exp (t, t, 2*numb_bits - norm);
mpz_tdiv_q (inv, t, d);
mpz_set_ui (t, 1L);
mpz_mul_2exp (t, t, numb_bits);
mpz_sub (inv, inv, t);
mpz_clear (t);
}
/* Calculate r satisfying r*d == 1 mod 2^n. */
void
mpz_invert_2exp (mpz_t r, mpz_t a, unsigned long n)
{
unsigned long i;
mpz_t inv, prod;
assert (mpz_odd_p (a));
mpz_init_set_ui (inv, 1L);
mpz_init (prod);
for (i = 1; i < n; i++)
{
mpz_mul (prod, inv, a);
if (mpz_tstbit (prod, i) != 0)
mpz_setbit (inv, i);
}
mpz_mul (prod, inv, a);
mpz_tdiv_r_2exp (prod, prod, n);
assert (mpz_cmp_ui (prod, 1L) == 0);
mpz_set (r, inv);
mpz_clear (inv);
mpz_clear (prod);
}
/* Calculate inv satisfying r*a == 1 mod 2^n. */
void
mpz_invert_ui_2exp (mpz_t r, unsigned long a, unsigned long n)
{
mpz_t az;
mpz_init_set_ui (az, a);
mpz_invert_2exp (r, az, n);
mpz_clear (az);
}
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