1 files changed, 118 insertions, 0 deletions
diff --git a/gmp-6.3.0/mpf/set_q.c b/gmp-6.3.0/mpf/set_q.c
new file mode 100644
index 0000000..b721e3a
--- /dev/null
+++ b/gmp-6.3.0/mpf/set_q.c
@@ -0,0 +1,118 @@
+/* mpf_set_q (mpf_t rop, mpq_t op) -- Convert the rational op to the float rop.
+
+Copyright 1996, 1999, 2001, 2002, 2004, 2005, 2016 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"
+
+
+/* As usual the aim is to produce PREC(r) limbs, with the high non-zero.  The
+   basic mpn_div_q produces a quotient of nsize-dsize+1 limbs, with either the
+   high or second highest limb non-zero.  We arrange for nsize-dsize+1 to equal
+   prec+1, hence giving either prec or prec+1 result limbs at PTR(r).
+
+   nsize-dsize+1 == prec+1 is achieved by adjusting num(q), either dropping low
+   limbs if it's too big, or padding with low zeros if it's too small.  The
+   full given den(q) is always used.
+
+   We cannot truncate den(q), because even when it's much bigger than prec the
+   last limbs can still influence the final quotient.  Often they don't, but we
+   leave optimization of that to mpn_div_q.
+
+   Enhancements:
+
+   The high quotient limb is non-zero when high{np,dsize} > {dp,dsize}.  We
+   could make that comparison and use qsize==prec instead of qsize==prec+1,
+   to save one limb in the division.  */
+
+void
+mpf_set_q (mpf_ptr r, mpq_srcptr q)
+{
+  mp_srcptr np, dp;
+  mp_size_t prec, nsize, dsize, qsize, prospective_qsize, tsize, zeros;
+  mp_size_t sign_quotient, high_zero;
+  mp_ptr qp, tp;
+  mp_exp_t exp;
+  TMP_DECL;
+
+  ASSERT (SIZ(&q->_mp_den) > 0);  /* canonical q */
+
+  nsize = SIZ (&q->_mp_num);
+  dsize = SIZ (&q->_mp_den);
+
+  if (UNLIKELY (nsize == 0))
+    {
+      SIZ (r) = 0;
+      EXP (r) = 0;
+      return;
+    }
+
+  TMP_MARK;
+
+  prec = PREC (r);
+  qp = PTR (r);
+
+  sign_quotient = nsize;
+  nsize = ABS (nsize);
+  np = PTR (&q->_mp_num);
+  dp = PTR (&q->_mp_den);
+
+  prospective_qsize = nsize - dsize + 1;  /* q from using given n,d sizes */
+  exp = prospective_qsize;                /* ie. number of integer limbs */
+  qsize = prec + 1;                       /* desired q */
+
+  zeros = qsize - prospective_qsize;      /* n zeros to get desired qsize */
+  tsize = nsize + zeros;                  /* size of intermediate numerator */
+  tp = TMP_ALLOC_LIMBS (tsize + 1);       /* +1 for mpn_div_q's scratch */
+
+  if (zeros > 0)
+    {
+      /* pad n with zeros into temporary space */
+      MPN_ZERO (tp, zeros);
+      MPN_COPY (tp+zeros, np, nsize);
+      np = tp;                            /* mpn_div_q allows this overlap */
+    }
+  else
+    {
+      /* shorten n to get desired qsize */
+      np -= zeros;
+    }
+
+  ASSERT (tsize-dsize+1 == qsize);
+  mpn_div_q (qp, np, tsize, dp, dsize, tp);
+
+  /* strip possible zero high limb */
+  high_zero = (qp[qsize-1] == 0);
+  qsize -= high_zero;
+  exp -= high_zero;
+
+  EXP (r) = exp;
+  SIZ (r) = sign_quotient >= 0 ? qsize : -qsize;
+
+  TMP_FREE;
+}