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authorUlrich Drepper <drepper@redhat.com>1999-07-14 00:54:57 +0000
committerUlrich Drepper <drepper@redhat.com>1999-07-14 00:54:57 +0000
commitabfbdde177c3a7155070dda1b2cdc8292054cc26 (patch)
treee021306b596381fbf8311d2b7eb294e918ff17c8 /sysdeps/ieee754/dbl-64/mpn2dbl.c
parent86421aa57ecfd70963ae66848bd6a6dd3b8e0fe6 (diff)
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Update.
Diffstat (limited to 'sysdeps/ieee754/dbl-64/mpn2dbl.c')
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diff --git a/sysdeps/ieee754/dbl-64/mpn2dbl.c b/sysdeps/ieee754/dbl-64/mpn2dbl.c
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+/* 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;
+}