1 files changed, 54 insertions, 0 deletions
diff --git a/sysdeps/ieee754/float128/mpn2float128.c b/sysdeps/ieee754/float128/mpn2float128.c
new file mode 100644
index 0000000000..1360abc5c0
--- /dev/null
+++ b/sysdeps/ieee754/float128/mpn2float128.c
@@ -0,0 +1,54 @@
+/* Convert a number in multi-precision format to _Float128.
+   Copyright (C) 2017-2018 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include "gmp.h"
+#include "gmp-impl.h"
+#include <float.h>
+#include <math.h>
+
+#include "ieee754_float128.h"
+
+/* Convert a multi-precision integer of the needed number of bits (113 for
+   binary128) and an integral power of two to a `_Float128' in IEEE854
+   quad-precision format.  */
+
+_Float128
+__mpn_construct_float128 (mp_srcptr frac_ptr, int expt, int sign)
+{
+  union ieee854_float128 u;
+
+  u.ieee.negative = sign;
+  u.ieee.exponent = expt + IEEE854_FLOAT128_BIAS;
+#if BITS_PER_MP_LIMB == 32
+  u.ieee.mantissa3 = frac_ptr[0];
+  u.ieee.mantissa2 = frac_ptr[1];
+  u.ieee.mantissa1 = frac_ptr[2];
+  u.ieee.mantissa0 = frac_ptr[3] & (((mp_limb_t) 1
+				     << (FLT128_MANT_DIG - 96)) - 1);
+#elif BITS_PER_MP_LIMB == 64
+  u.ieee.mantissa3 = frac_ptr[0] & (((mp_limb_t) 1 << 32) - 1);
+  u.ieee.mantissa2 = frac_ptr[0] >> 32;
+  u.ieee.mantissa1 = frac_ptr[1] & (((mp_limb_t) 1 << 32) - 1);
+  u.ieee.mantissa0 = (frac_ptr[1] >> 32) & (((mp_limb_t) 1
+					     << (FLT128_MANT_DIG - 96)) - 1);
+#else
+  #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"
+#endif
+
+  return u.d;
+}