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/root.c b/third_party/gmp/mpz/root.c
new file mode 100644
index 0000000..7119bbc
--- /dev/null
+++ b/third_party/gmp/mpz/root.c
@@ -0,0 +1,92 @@
+/* mpz_root(root, u, nth) -- Set ROOT to floor(U^(1/nth)).
+ Return an indication if the result is exact.
+
+Copyright 1999-2003, 2005, 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 <stdio.h> /* for NULL */
+#include "gmp-impl.h"
+
+int
+mpz_root (mpz_ptr root, mpz_srcptr u, unsigned long int nth)
+{
+ mp_ptr rootp, up;
+ mp_size_t us, un, rootn, remn;
+ TMP_DECL;
+
+ us = SIZ(u);
+
+ /* even roots of negatives provoke an exception */
+ if (UNLIKELY (us < 0 && (nth & 1) == 0))
+ SQRT_OF_NEGATIVE;
+
+ /* root extraction interpreted as c^(1/nth) means a zeroth root should
+ provoke a divide by zero, do this even if c==0 */
+ if (UNLIKELY (nth == 0))
+ DIVIDE_BY_ZERO;
+
+ if (us == 0)
+ {
+ if (root != NULL)
+ SIZ(root) = 0;
+ return 1; /* exact result */
+ }
+
+ un = ABS (us);
+ rootn = (un - 1) / nth + 1;
+
+ TMP_MARK;
+
+ /* FIXME: Perhaps disallow root == NULL */
+ if (root != NULL && u != root)
+ rootp = MPZ_NEWALLOC (root, rootn);
+ else
+ rootp = TMP_ALLOC_LIMBS (rootn);
+
+ up = PTR(u);
+
+ if (nth == 1)
+ {
+ MPN_COPY (rootp, up, un);
+ remn = 0;
+ }
+ else
+ {
+ remn = mpn_rootrem (rootp, NULL, up, un, (mp_limb_t) nth);
+ }
+
+ if (root != NULL)
+ {
+ SIZ(root) = us >= 0 ? rootn : -rootn;
+ if (u == root)
+ MPN_COPY (up, rootp, rootn);
+ }
+
+ TMP_FREE;
+ return remn == 0;
+}