1 files changed, 46 insertions, 0 deletions
diff --git a/sysdeps/ieee754/dbl-64/mpn2dbl.c b/sysdeps/ieee754/dbl-64/mpn2dbl.c
new file mode 100644
index 0000000000..8145eb9c3d
--- /dev/null
+++ b/sysdeps/ieee754/dbl-64/mpn2dbl.c
@@ -0,0 +1,46 @@
+/* Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include "gmp.h"
+#include "gmp-impl.h"
+#include <ieee754.h>
+#include <float.h>
+
+/* Convert a multi-precision integer of the needed number of bits (53 for
+   double) and an integral power of two to a `double' in IEEE754 double-
+   precision format.  */
+
+double
+__mpn_construct_double (mp_srcptr frac_ptr, int expt, int negative)
+{
+  union ieee754_double u;
+
+  u.ieee.negative = negative;
+  u.ieee.exponent = expt + IEEE754_DOUBLE_BIAS;
+#if BITS_PER_MP_LIMB == 32
+  u.ieee.mantissa1 = frac_ptr[0];
+  u.ieee.mantissa0 = frac_ptr[1] & ((1 << (DBL_MANT_DIG - 32)) - 1);
+#elif BITS_PER_MP_LIMB == 64
+  u.ieee.mantissa1 = frac_ptr[0] & ((1L << 32) - 1);
+  u.ieee.mantissa0 = (frac_ptr[0] >> 32) & ((1 << (DBL_MANT_DIG - 32)) - 1);
+#else
+  #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"
+#endif
+
+  return u.d;
+}