Add libgmp 6.2.0 to third_party
Don't build it yet. That will come in the next review.
Change-Id: Idf3266558165e5ab45f4a41c98cc8c838c8244d5
diff --git a/third_party/gmp/mpz/powm_ui.c b/third_party/gmp/mpz/powm_ui.c
new file mode 100644
index 0000000..23d3ed8
--- /dev/null
+++ b/third_party/gmp/mpz/powm_ui.c
@@ -0,0 +1,281 @@
+/* mpz_powm_ui(res,base,exp,mod) -- Set R to (B^E) mod M.
+
+ Contributed to the GNU project by Torbjörn Granlund.
+
+Copyright 1991, 1993, 1994, 1996, 1997, 2000-2002, 2005, 2008, 2009,
+2011-2013, 2015 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-impl.h"
+#include "longlong.h"
+
+
+/* This code is very old, and should be rewritten to current GMP standard. It
+ is slower than mpz_powm for large exponents, but also for small exponents
+ when the mod argument is small.
+
+ As an intermediate solution, we now deflect to mpz_powm for exponents >= 20.
+*/
+
+/*
+ b ^ e mod m res
+ 0 0 0 ?
+ 0 e 0 ?
+ 0 0 m ?
+ 0 e m 0
+ b 0 0 ?
+ b e 0 ?
+ b 0 m 1 mod m
+ b e m b^e mod m
+*/
+
+static void
+mod (mp_ptr np, mp_size_t nn, mp_srcptr dp, mp_size_t dn, gmp_pi1_t *dinv, mp_ptr tp)
+{
+ mp_ptr qp = tp;
+
+ if (dn == 1)
+ {
+ np[0] = mpn_divrem_1 (qp, (mp_size_t) 0, np, nn, dp[0]);
+ }
+ else if (dn == 2)
+ {
+ mpn_div_qr_2n_pi1 (qp, np, np, nn, dp[1], dp[0], dinv->inv32);
+ }
+ else if (BELOW_THRESHOLD (dn, DC_DIV_QR_THRESHOLD) ||
+ BELOW_THRESHOLD (nn - dn, DC_DIV_QR_THRESHOLD))
+ {
+ mpn_sbpi1_div_qr (qp, np, nn, dp, dn, dinv->inv32);
+ }
+ else if (BELOW_THRESHOLD (dn, MUPI_DIV_QR_THRESHOLD) || /* fast condition */
+ BELOW_THRESHOLD (nn, 2 * MU_DIV_QR_THRESHOLD) || /* fast condition */
+ (double) (2 * (MU_DIV_QR_THRESHOLD - MUPI_DIV_QR_THRESHOLD)) * dn /* slow... */
+ + (double) MUPI_DIV_QR_THRESHOLD * nn > (double) dn * nn) /* ...condition */
+ {
+ mpn_dcpi1_div_qr (qp, np, nn, dp, dn, dinv);
+ }
+ else
+ {
+ /* We need to allocate separate remainder area, since mpn_mu_div_qr does
+ not handle overlap between the numerator and remainder areas.
+ FIXME: Make it handle such overlap. */
+ mp_ptr rp, scratch;
+ mp_size_t itch;
+ TMP_DECL;
+ TMP_MARK;
+
+ itch = mpn_mu_div_qr_itch (nn, dn, 0);
+ rp = TMP_BALLOC_LIMBS (dn);
+ scratch = TMP_BALLOC_LIMBS (itch);
+
+ mpn_mu_div_qr (qp, rp, np, nn, dp, dn, scratch);
+ MPN_COPY (np, rp, dn);
+
+ TMP_FREE;
+ }
+}
+
+/* Compute t = a mod m, a is defined by (ap,an), m is defined by (mp,mn), and
+ t is defined by (tp,mn). */
+static void
+reduce (mp_ptr tp, mp_srcptr ap, mp_size_t an, mp_srcptr mp, mp_size_t mn, gmp_pi1_t *dinv)
+{
+ mp_ptr rp, scratch;
+ TMP_DECL;
+ TMP_MARK;
+
+ TMP_ALLOC_LIMBS_2 (rp, an, scratch, an - mn + 1);
+ MPN_COPY (rp, ap, an);
+ mod (rp, an, mp, mn, dinv, scratch);
+ MPN_COPY (tp, rp, mn);
+
+ TMP_FREE;
+}
+
+void
+mpz_powm_ui (mpz_ptr r, mpz_srcptr b, unsigned long int el, mpz_srcptr m)
+{
+ if (el < 20)
+ {
+ mp_ptr xp, tp, mp, bp, scratch;
+ mp_size_t xn, tn, mn, bn;
+ int m_zero_cnt;
+ int c;
+ mp_limb_t e, m2;
+ gmp_pi1_t dinv;
+ TMP_DECL;
+
+ mp = PTR(m);
+ mn = ABSIZ(m);
+ if (UNLIKELY (mn == 0))
+ DIVIDE_BY_ZERO;
+
+ if (el <= 1)
+ {
+ if (el == 1)
+ {
+ mpz_mod (r, b, m);
+ return;
+ }
+ /* Exponent is zero, result is 1 mod M, i.e., 1 or 0 depending on if
+ M equals 1. */
+ SIZ(r) = mn != 1 || mp[0] != 1;
+ MPZ_NEWALLOC (r, 1)[0] = 1;
+ return;
+ }
+
+ TMP_MARK;
+
+ /* Normalize m (i.e. make its most significant bit set) as required by
+ division functions below. */
+ count_leading_zeros (m_zero_cnt, mp[mn - 1]);
+ m_zero_cnt -= GMP_NAIL_BITS;
+ if (m_zero_cnt != 0)
+ {
+ mp_ptr new_mp = TMP_ALLOC_LIMBS (mn);
+ mpn_lshift (new_mp, mp, mn, m_zero_cnt);
+ mp = new_mp;
+ }
+
+ m2 = mn == 1 ? 0 : mp[mn - 2];
+ invert_pi1 (dinv, mp[mn - 1], m2);
+
+ bn = ABSIZ(b);
+ bp = PTR(b);
+ if (bn > mn)
+ {
+ /* Reduce possibly huge base. Use a function call to reduce, since we
+ don't want the quotient allocation to live until function return. */
+ mp_ptr new_bp = TMP_ALLOC_LIMBS (mn);
+ reduce (new_bp, bp, bn, mp, mn, &dinv);
+ bp = new_bp;
+ bn = mn;
+ /* Canonicalize the base, since we are potentially going to multiply with
+ it quite a few times. */
+ MPN_NORMALIZE (bp, bn);
+ }
+
+ if (bn == 0)
+ {
+ SIZ(r) = 0;
+ TMP_FREE;
+ return;
+ }
+
+ TMP_ALLOC_LIMBS_3 (xp, mn, scratch, mn + 1, tp, 2 * mn + 1);
+
+ MPN_COPY (xp, bp, bn);
+ xn = bn;
+
+ e = el;
+ count_leading_zeros (c, e);
+ e = (e << c) << 1; /* shift the exp bits to the left, lose msb */
+ c = GMP_LIMB_BITS - 1 - c;
+
+ ASSERT (c != 0); /* el > 1 */
+ {
+ /* Main loop. */
+ do
+ {
+ mpn_sqr (tp, xp, xn);
+ tn = 2 * xn; tn -= tp[tn - 1] == 0;
+ if (tn < mn)
+ {
+ MPN_COPY (xp, tp, tn);
+ xn = tn;
+ }
+ else
+ {
+ mod (tp, tn, mp, mn, &dinv, scratch);
+ MPN_COPY (xp, tp, mn);
+ xn = mn;
+ }
+
+ if ((mp_limb_signed_t) e < 0)
+ {
+ mpn_mul (tp, xp, xn, bp, bn);
+ tn = xn + bn; tn -= tp[tn - 1] == 0;
+ if (tn < mn)
+ {
+ MPN_COPY (xp, tp, tn);
+ xn = tn;
+ }
+ else
+ {
+ mod (tp, tn, mp, mn, &dinv, scratch);
+ MPN_COPY (xp, tp, mn);
+ xn = mn;
+ }
+ }
+ e <<= 1;
+ c--;
+ }
+ while (c != 0);
+ }
+
+ /* We shifted m left m_zero_cnt steps. Adjust the result by reducing it
+ with the original M. */
+ if (m_zero_cnt != 0)
+ {
+ mp_limb_t cy;
+ cy = mpn_lshift (tp, xp, xn, m_zero_cnt);
+ tp[xn] = cy; xn += cy != 0;
+
+ if (xn >= mn)
+ {
+ mod (tp, xn, mp, mn, &dinv, scratch);
+ xn = mn;
+ }
+ mpn_rshift (xp, tp, xn, m_zero_cnt);
+ }
+ MPN_NORMALIZE (xp, xn);
+
+ if ((el & 1) != 0 && SIZ(b) < 0 && xn != 0)
+ {
+ mp = PTR(m); /* want original, unnormalized m */
+ mpn_sub (xp, mp, mn, xp, xn);
+ xn = mn;
+ MPN_NORMALIZE (xp, xn);
+ }
+ MPZ_NEWALLOC (r, xn);
+ SIZ (r) = xn;
+ MPN_COPY (PTR(r), xp, xn);
+
+ TMP_FREE;
+ }
+ else
+ {
+ /* For large exponents, fake an mpz_t exponent and deflect to the more
+ sophisticated mpz_powm. */
+ mpz_t e;
+ mp_limb_t ep[LIMBS_PER_ULONG];
+ MPZ_FAKE_UI (e, ep, el);
+ mpz_powm (r, b, e, m);
+ }
+}