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/divis_2exp.c b/third_party/gmp/mpz/divis_2exp.c
new file mode 100644
index 0000000..4ecb0c0
--- /dev/null
+++ b/third_party/gmp/mpz/divis_2exp.c
@@ -0,0 +1,60 @@
+/* mpz_divisible_2exp_p -- mpz by 2^n divisibility test
+
+Copyright 2001, 2002 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"
+
+
+int
+mpz_divisible_2exp_p (mpz_srcptr a, mp_bitcnt_t d) __GMP_NOTHROW
+{
+ mp_size_t i, dlimbs;
+ unsigned dbits;
+ mp_ptr ap;
+ mp_limb_t dmask;
+ mp_size_t asize;
+
+ asize = ABSIZ(a);
+ dlimbs = d / GMP_NUMB_BITS;
+
+ /* if d covers the whole of a, then only a==0 is divisible */
+ if (asize <= dlimbs)
+ return asize == 0;
+
+ /* whole limbs must be zero */
+ ap = PTR(a);
+ for (i = 0; i < dlimbs; i++)
+ if (ap[i] != 0)
+ return 0;
+
+ /* left over bits must be zero */
+ dbits = d % GMP_NUMB_BITS;
+ dmask = (CNST_LIMB(1) << dbits) - 1;
+ return (ap[dlimbs] & dmask) == 0;
+}