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diff --git a/gmp/mpf/add.c b/gmp/mpf/add.c
new file mode 100644
index 00000000..341b36b4
--- /dev/null
+++ b/gmp/mpf/add.c
@@ -0,0 +1,173 @@
+/* mpf_add -- Add two floats.
+
+Copyright 1993, 1994, 1996, 2000, 2001, 2005 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 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.
+
+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 Lesser General Public
+License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.  */
+
+#include "gmp.h"
+#include "gmp-impl.h"
+
+void
+mpf_add (mpf_ptr r, mpf_srcptr u, mpf_srcptr v)
+{
+  mp_srcptr up, vp;
+  mp_ptr rp, tp;
+  mp_size_t usize, vsize, rsize;
+  mp_size_t prec;
+  mp_exp_t uexp;
+  mp_size_t ediff;
+  mp_limb_t cy;
+  int negate;
+  TMP_DECL;
+
+  usize = u->_mp_size;
+  vsize = v->_mp_size;
+
+  /* Handle special cases that don't work in generic code below.  */
+  if (usize == 0)
+    {
+    set_r_v_maybe:
+      if (r != v)
+        mpf_set (r, v);
+      return;
+    }
+  if (vsize == 0)
+    {
+      v = u;
+      goto set_r_v_maybe;
+    }
+
+  /* If signs of U and V are different, perform subtraction.  */
+  if ((usize ^ vsize) < 0)
+    {
+      __mpf_struct v_negated;
+      v_negated._mp_size = -vsize;
+      v_negated._mp_exp = v->_mp_exp;
+      v_negated._mp_d = v->_mp_d;
+      mpf_sub (r, u, &v_negated);
+      return;
+    }
+
+  TMP_MARK;
+
+  /* Signs are now known to be the same.  */
+  negate = usize < 0;
+
+  /* Make U be the operand with the largest exponent.  */
+  if (u->_mp_exp < v->_mp_exp)
+    {
+      mpf_srcptr t;
+      t = u; u = v; v = t;
+      usize = u->_mp_size;
+      vsize = v->_mp_size;
+    }
+
+  usize = ABS (usize);
+  vsize = ABS (vsize);
+  up = u->_mp_d;
+  vp = v->_mp_d;
+  rp = r->_mp_d;
+  prec = r->_mp_prec;
+  uexp = u->_mp_exp;
+  ediff = u->_mp_exp - v->_mp_exp;
+
+  /* If U extends beyond PREC, ignore the part that does.  */
+  if (usize > prec)
+    {
+      up += usize - prec;
+      usize = prec;
+    }
+
+  /* If V extends beyond PREC, ignore the part that does.
+     Note that this may make vsize negative.  */
+  if (vsize + ediff > prec)
+    {
+      vp += vsize + ediff - prec;
+      vsize = prec - ediff;
+    }
+
+#if 0
+  /* Locate the least significant non-zero limb in (the needed parts
+     of) U and V, to simplify the code below.  */
+  while (up[0] == 0)
+    up++, usize--;
+  while (vp[0] == 0)
+    vp++, vsize--;
+#endif
+
+  /* Allocate temp space for the result.  Allocate
+     just vsize + ediff later???  */
+  tp = (mp_ptr) TMP_ALLOC (prec * BYTES_PER_MP_LIMB);
+
+  if (ediff >= prec)
+    {
+      /* V completely cancelled.  */
+      if (rp != up)
+	MPN_COPY_INCR (rp, up, usize);
+      rsize = usize;
+    }
+  else
+    {
+      /* uuuu     |  uuuu     |  uuuu     |  uuuu     |  uuuu    */
+      /* vvvvvvv  |  vv       |    vvvvv  |    v      |       vv */
+
+      if (usize > ediff)
+	{
+	  /* U and V partially overlaps.  */
+	  if (vsize + ediff <= usize)
+	    {
+	      /* uuuu     */
+	      /*   v      */
+	      mp_size_t size;
+	      size = usize - ediff - vsize;
+	      MPN_COPY (tp, up, size);
+	      cy = mpn_add (tp + size, up + size, usize - size, vp, vsize);
+	      rsize = usize;
+	    }
+	  else
+	    {
+	      /* uuuu     */
+	      /*   vvvvv  */
+	      mp_size_t size;
+	      size = vsize + ediff - usize;
+	      MPN_COPY (tp, vp, size);
+	      cy = mpn_add (tp + size, up, usize, vp + size, usize - ediff);
+	      rsize = vsize + ediff;
+	    }
+	}
+      else
+	{
+	  /* uuuu     */
+	  /*      vv  */
+	  mp_size_t size;
+	  size = vsize + ediff - usize;
+	  MPN_COPY (tp, vp, vsize);
+	  MPN_ZERO (tp + vsize, ediff - usize);
+	  MPN_COPY (tp + size, up, usize);
+	  cy = 0;
+	  rsize = size + usize;
+	}
+
+      MPN_COPY (rp, tp, rsize);
+      rp[rsize] = cy;
+      rsize += cy;
+      uexp += cy;
+    }
+
+  r->_mp_size = negate ? -rsize : rsize;
+  r->_mp_exp = uexp;
+  TMP_FREE;
+}