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/mpn/generic/random2.c b/third_party/gmp/mpn/generic/random2.c
new file mode 100644
index 0000000..1eede67
--- /dev/null
+++ b/third_party/gmp/mpn/generic/random2.c
@@ -0,0 +1,105 @@
+/* mpn_random2 -- Generate random numbers with relatively long strings
+ of ones and zeroes. Suitable for border testing.
+
+Copyright 1992-1994, 1996, 2000-2002, 2004, 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-impl.h"
+
+static void gmp_rrandomb (mp_ptr, gmp_randstate_t, mp_bitcnt_t);
+
+/* Ask _gmp_rand for 32 bits per call unless that's more than a limb can hold.
+ Thus, we get the same random number sequence in the common cases.
+ FIXME: We should always generate the same random number sequence! */
+#if GMP_NUMB_BITS < 32
+#define BITS_PER_RANDCALL GMP_NUMB_BITS
+#else
+#define BITS_PER_RANDCALL 32
+#endif
+
+void
+mpn_random2 (mp_ptr rp, mp_size_t n)
+{
+ gmp_randstate_ptr rstate = RANDS;
+ int bit_pos; /* bit number of least significant bit where
+ next bit field to be inserted */
+ mp_limb_t ran, ranm; /* buffer for random bits */
+
+ /* FIXME: Is n==0 supposed to be allowed? */
+ ASSERT (n >= 0);
+
+ _gmp_rand (&ranm, rstate, BITS_PER_RANDCALL);
+ ran = ranm;
+
+ /* Start off at a random bit position in the most significant limb. */
+ bit_pos = ran % GMP_NUMB_BITS;
+
+ gmp_rrandomb (rp, rstate, n * GMP_NUMB_BITS - bit_pos);
+}
+
+static void
+gmp_rrandomb (mp_ptr rp, gmp_randstate_t rstate, mp_bitcnt_t nbits)
+{
+ mp_bitcnt_t bi;
+ mp_limb_t ranm; /* buffer for random bits */
+ unsigned cap_chunksize, chunksize;
+ mp_size_t i;
+
+ /* Set entire result to 111..1 */
+ i = BITS_TO_LIMBS (nbits) - 1;
+ rp[i] = GMP_NUMB_MAX >> (GMP_NUMB_BITS - (nbits % GMP_NUMB_BITS)) % GMP_NUMB_BITS;
+ for (i = i - 1; i >= 0; i--)
+ rp[i] = GMP_NUMB_MAX;
+
+ _gmp_rand (&ranm, rstate, BITS_PER_RANDCALL);
+ cap_chunksize = nbits / (ranm % 4 + 1);
+ cap_chunksize += cap_chunksize == 0; /* make it at least 1 */
+
+ bi = nbits;
+
+ for (;;)
+ {
+ _gmp_rand (&ranm, rstate, BITS_PER_RANDCALL);
+ chunksize = 1 + ranm % cap_chunksize;
+ bi = (bi < chunksize) ? 0 : bi - chunksize;
+
+ if (bi == 0)
+ break; /* low chunk is ...1 */
+
+ rp[bi / GMP_NUMB_BITS] ^= CNST_LIMB (1) << bi % GMP_NUMB_BITS;
+
+ _gmp_rand (&ranm, rstate, BITS_PER_RANDCALL);
+ chunksize = 1 + ranm % cap_chunksize;
+ bi = (bi < chunksize) ? 0 : bi - chunksize;
+
+ mpn_incr_u (rp + bi / GMP_NUMB_BITS, CNST_LIMB (1) << bi % GMP_NUMB_BITS);
+
+ if (bi == 0)
+ break; /* low chunk is ...0 */
+ }
+}