mirror of
https://review.haiku-os.org/buildtools
synced 2025-02-12 08:47:41 +01:00
f133d007f9
Old version was from 2012-05-06, 6.1.2 is from 2016-12-16 A lot of support for newer processors and speedups since then See gmp/NEWS for details
105 lines
2.3 KiB
C
105 lines
2.3 KiB
C
/* mpz_powm_sec(res,base,exp,mod) -- Set R to (U^E) mod M.
|
|
|
|
Contributed to the GNU project by Torbjorn Granlund.
|
|
|
|
Copyright 1991, 1993, 1994, 1996, 1997, 2000-2002, 2005, 2008, 2009, 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 either:
|
|
|
|
* 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.
|
|
|
|
or
|
|
|
|
* the GNU General Public License as published by the Free Software
|
|
Foundation; either version 2 of the License, or (at your option) any
|
|
later version.
|
|
|
|
or both in parallel, as here.
|
|
|
|
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 General Public License
|
|
for more details.
|
|
|
|
You should have received copies of the GNU General Public License and the
|
|
GNU Lesser General Public License along with the GNU MP Library. If not,
|
|
see https://www.gnu.org/licenses/. */
|
|
|
|
|
|
#include "gmp.h"
|
|
#include "gmp-impl.h"
|
|
|
|
|
|
void
|
|
mpz_powm_sec (mpz_ptr r, mpz_srcptr b, mpz_srcptr e, mpz_srcptr m)
|
|
{
|
|
mp_size_t n;
|
|
mp_ptr rp, tp;
|
|
mp_srcptr bp, ep, mp;
|
|
mp_size_t rn, bn, es, en;
|
|
TMP_DECL;
|
|
|
|
n = ABSIZ(m);
|
|
|
|
mp = PTR(m);
|
|
|
|
if (UNLIKELY ((n == 0) || (mp[0] % 2 == 0)))
|
|
DIVIDE_BY_ZERO;
|
|
|
|
es = SIZ(e);
|
|
if (UNLIKELY (es <= 0))
|
|
{
|
|
if (es == 0)
|
|
{
|
|
/* b^0 mod m, b is anything and m is non-zero.
|
|
Result is 1 mod m, i.e., 1 or 0 depending on if m = 1. */
|
|
SIZ(r) = n != 1 || mp[0] != 1;
|
|
PTR(r)[0] = 1;
|
|
return;
|
|
}
|
|
DIVIDE_BY_ZERO;
|
|
}
|
|
en = es;
|
|
|
|
bn = ABSIZ(b);
|
|
|
|
if (UNLIKELY (bn == 0))
|
|
{
|
|
SIZ(r) = 0;
|
|
return;
|
|
}
|
|
|
|
TMP_MARK;
|
|
tp = TMP_ALLOC_LIMBS (n + mpn_sec_powm_itch (bn, en * GMP_NUMB_BITS, n));
|
|
|
|
rp = tp; tp += n;
|
|
|
|
bp = PTR(b);
|
|
ep = PTR(e);
|
|
|
|
mpn_sec_powm (rp, bp, bn, ep, en * GMP_NUMB_BITS, mp, n, tp);
|
|
|
|
rn = n;
|
|
|
|
MPN_NORMALIZE (rp, rn);
|
|
|
|
if ((ep[0] & 1) && SIZ(b) < 0 && rn != 0)
|
|
{
|
|
mpn_sub (rp, PTR(m), n, rp, rn);
|
|
rn = n;
|
|
MPN_NORMALIZE (rp, rn);
|
|
}
|
|
|
|
MPZ_REALLOC (r, rn);
|
|
SIZ(r) = rn;
|
|
MPN_COPY (PTR(r), rp, rn);
|
|
|
|
TMP_FREE;
|
|
}
|