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/mpq/set_f.c b/third_party/gmp/mpq/set_f.c
new file mode 100644
index 0000000..581d4fc
--- /dev/null
+++ b/third_party/gmp/mpq/set_f.c
@@ -0,0 +1,106 @@
+/* mpq_set_f -- set an mpq from an mpf.
+
+Copyright 2000-2002, 2018 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"
+
+
+void
+mpq_set_f (mpq_ptr q, mpf_srcptr f)
+{
+ mp_size_t fexp = EXP(f);
+ mp_ptr fptr = PTR(f);
+ mp_size_t fsize = SIZ(f);
+ mp_size_t abs_fsize = ABS(fsize);
+ mp_limb_t flow;
+
+ if (fsize == 0)
+ {
+ /* set q=0 */
+ SIZ(NUM(q)) = 0;
+ SIZ(DEN(q)) = 1;
+ MPZ_NEWALLOC (DEN(q), 1)[0] = 1;
+ return;
+ }
+
+ /* strip low zero limbs from f */
+ flow = *fptr;
+ MPN_STRIP_LOW_ZEROS_NOT_ZERO (fptr, abs_fsize, flow);
+
+ if (fexp >= abs_fsize)
+ {
+ /* radix point is to the right of the limbs, no denominator */
+ mp_ptr num_ptr;
+
+ num_ptr = MPZ_NEWALLOC (mpq_numref (q), fexp);
+ MPN_ZERO (num_ptr, fexp - abs_fsize);
+ MPN_COPY (num_ptr + fexp - abs_fsize, fptr, abs_fsize);
+
+ SIZ(NUM(q)) = fsize >= 0 ? fexp : -fexp;
+ SIZ(DEN(q)) = 1;
+ MPZ_NEWALLOC (DEN(q), 1)[0] = 1;
+ }
+ else
+ {
+ /* radix point is within or to the left of the limbs, use denominator */
+ mp_ptr num_ptr, den_ptr;
+ mp_size_t den_size;
+
+ den_size = abs_fsize - fexp;
+ num_ptr = MPZ_NEWALLOC (mpq_numref (q), abs_fsize);
+ den_ptr = MPZ_NEWALLOC (mpq_denref (q), den_size+1);
+
+ if (flow & 1)
+ {
+ /* no powers of two to strip from numerator */
+
+ MPN_COPY (num_ptr, fptr, abs_fsize);
+ MPN_ZERO (den_ptr, den_size);
+ den_ptr[den_size] = 1;
+ }
+ else
+ {
+ /* right shift numerator, adjust denominator accordingly */
+ int shift;
+
+ den_size--;
+ count_trailing_zeros (shift, flow);
+
+ mpn_rshift (num_ptr, fptr, abs_fsize, shift);
+ abs_fsize -= (num_ptr[abs_fsize-1] == 0);
+
+ MPN_ZERO (den_ptr, den_size);
+ den_ptr[den_size] = GMP_LIMB_HIGHBIT >> (shift-1);
+ }
+
+ SIZ(NUM(q)) = fsize >= 0 ? abs_fsize : -abs_fsize;
+ SIZ(DEN(q)) = den_size + 1;
+ }
+}