153 lines
4.0 KiB
C
153 lines
4.0 KiB
C
/*
|
|
(C) Copyright IBM Corp. 2009
|
|
|
|
All rights reserved.
|
|
|
|
Redistribution and use in source and binary forms, with or without
|
|
modification, are permitted provided that the following conditions are met:
|
|
|
|
* Redistributions of source code must retain the above copyright notice,
|
|
this list of conditions and the following disclaimer.
|
|
* Redistributions in binary form must reproduce the above copyright
|
|
notice, this list of conditions and the following disclaimer in the
|
|
documentation and/or other materials provided with the distribution.
|
|
* Neither the name of IBM nor the names of its contributors may be
|
|
used to endorse or promote products derived from this software without
|
|
specific prior written permission.
|
|
|
|
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
|
|
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
|
|
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
#include <math.h>
|
|
#include <float.h>
|
|
#include "local.h"
|
|
|
|
/* On platforms where long double is as wide as double. */
|
|
#if defined(_LDBL_EQ_DBL)
|
|
long double
|
|
frexpl (long double x, int *eptr)
|
|
{
|
|
return frexp(x, eptr);
|
|
}
|
|
#else /* !_DBL_EQ_DBL */
|
|
# if (LDBL_MANT_DIG == 53) /* 64-bit long double */
|
|
static const double scale = 0x1p54;
|
|
|
|
union ldbl {
|
|
long double x;
|
|
struct {
|
|
# ifdef __IEEE_LITTLE_ENDIAN /* for Intel CPU */
|
|
__uint32_t fracl;
|
|
__uint32_t frach:20;
|
|
__uint32_t exp:11;
|
|
__uint32_t sign:1;
|
|
# endif
|
|
# ifdef __IEEE_BIG_ENDIAN
|
|
__uint32_t sign:1;
|
|
__uint32_t exp:11;
|
|
__uint32_t frach:20;
|
|
# ifndef ___IEEE_BYTES_LITTLE_ENDIAN
|
|
# else /* ARMEL without __VFP_FP__ */
|
|
__uint32_t frach:20;
|
|
__uint32_t exp:11;
|
|
__uint32_t sign:1;
|
|
# endif
|
|
__uint32_t fracl;
|
|
# endif
|
|
} u32;
|
|
};
|
|
# elif (LDBL_MANT_DIG == 64) /* 80-bit long double */
|
|
static const double scale = 0x1p65;
|
|
|
|
union ldbl {
|
|
long double x;
|
|
struct {
|
|
# ifdef __IEEE_LITTLE_ENDIAN /* for Intel CPU */
|
|
__uint32_t fracl;
|
|
__uint32_t frach;
|
|
__uint32_t exp:15;
|
|
__uint32_t sign:1;
|
|
__uint32_t pad:16;
|
|
# endif
|
|
# ifdef __IEEE_BIG_ENDIAN
|
|
# ifndef ___IEEE_BYTES_LITTLE_ENDIAN /* for m86k */
|
|
__uint32_t sign:1;
|
|
__uint32_t exp:15;
|
|
__uint32_t pad:16;
|
|
# else /* ARM FPA10 math copprocessor */
|
|
__uint32_t exp:15;
|
|
__uint32_t pad:16;
|
|
__uint32_t sign:1;
|
|
# endif
|
|
__uint32_t frach;
|
|
__uint32_t fracl;
|
|
# endif
|
|
} u32;
|
|
};
|
|
# elif (LDBL_MANT_DIG == 113) /* 128-bit long double */
|
|
static const double scale = 0x1p114;
|
|
|
|
union ldbl {
|
|
long double x;
|
|
struct {
|
|
# ifdef __IEEE_LITTLE_ENDIAN
|
|
__uint32_t fracl;
|
|
__uint32_t fraclm;
|
|
__uint32_t frachm;
|
|
__uint32_t frach:16;
|
|
__uint32_t exp:15;
|
|
__uint32_t sign:1;
|
|
# endif
|
|
# ifdef __IEEE_BIG_ENDIAN
|
|
# ifndef ___IEEE_BYTES_LITTLE_ENDIAN
|
|
__uint32_t sign:1;
|
|
__uint32_t exp:15;
|
|
__uint32_t frach:16;
|
|
# else /* ARMEL without __VFP_FP__ */
|
|
__uint32_t frach:16;
|
|
__uint32_t exp:15;
|
|
__uint32_t sign:1;
|
|
# endif
|
|
__uint32_t frachm;
|
|
__uint32_t fraclm;
|
|
__uint32_t fracl;
|
|
# endif
|
|
} u32;
|
|
};
|
|
# else
|
|
# error Unsupported long double format.
|
|
# endif
|
|
|
|
static const int scale_exp = LDBL_MANT_DIG + 1;
|
|
|
|
long double
|
|
frexpl (long double x, int *eptr)
|
|
{
|
|
union ldbl u;
|
|
u.x = x;
|
|
int e = u.u32.exp;
|
|
*eptr = 0;
|
|
if (e == (LDBL_MAX_EXP*2 - 1) || x == 0)
|
|
return x; /* inf,nan,0 */
|
|
if (e == 0) /* subnormal */
|
|
{
|
|
u.x *= scale;
|
|
e = u.u32.exp;
|
|
*eptr -= scale_exp;
|
|
}
|
|
*eptr += e - (LDBL_MAX_EXP - 2);
|
|
u.u32.exp = LDBL_MAX_EXP - 2; /* -1 */
|
|
return u.x;
|
|
}
|
|
#endif /* !_LDBL_EQ_DBL */
|