glibc/sysdeps/ieee754/ldbl-128/s_asinhl.c
Joseph Myers 8db3cdefef Fix asinh missing underflows (bug 16350).
Similar to various other bugs in this area, some asinh implementations
do not raise the underflow exception for subnormal arguments, when the
result is tiny and inexact.  This patch forces the exception in a
similar way to previous fixes.

Tested for x86_64, x86 and mips64.

	[BZ #16350]
	* sysdeps/i386/fpu/s_asinh.S (__asinh): Force underflow exception
	for arguments with small absolute value.
	* sysdeps/i386/fpu/s_asinhf.S (__asinhf): Likewise.
	* sysdeps/i386/fpu/s_asinhl.S (__asinhl): Likewise.
	* sysdeps/ieee754/dbl-64/s_asinh.c: Include <float.h>.
	(__asinh): Force underflow exception for arguments with small
	absolute value.
	* sysdeps/ieee754/flt-32/s_asinhf.c: Include <float.h>.
	(__asinhf): Force underflow exception for arguments with small
	absolute value.
	* sysdeps/ieee754/ldbl-128/s_asinhl.c: Include <float.h>.
	(__asinhl): Force underflow exception for arguments with small
	absolute value.
	* sysdeps/ieee754/ldbl-128ibm/s_asinhl.c: Include <float.h>.
	(__asinhl): Force underflow exception for arguments with small
	absolute value.
	* sysdeps/ieee754/ldbl-96/s_asinhl.c: Include <float.h>.
	(__asinhl): Force underflow exception for arguments with small
	absolute value.
	* math/auto-libm-test-in: Do not mark underflow exceptions as
	possibly missing for bug 16350.
	* math/auto-libm-test-out: Regenerated.
2015-06-18 23:27:41 +00:00

84 lines
2.1 KiB
C

/* s_asinhl.c -- long double version of s_asinh.c.
* Conversion to long double by Ulrich Drepper,
* Cygnus Support, drepper@cygnus.com.
*/
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#if defined(LIBM_SCCS) && !defined(lint)
static char rcsid[] = "$NetBSD: $";
#endif
/* asinhl(x)
* Method :
* Based on
* asinhl(x) = signl(x) * logl [ |x| + sqrtl(x*x+1) ]
* we have
* asinhl(x) := x if 1+x*x=1,
* := signl(x)*(logl(x)+ln2)) for large |x|, else
* := signl(x)*logl(2|x|+1/(|x|+sqrtl(x*x+1))) if|x|>2, else
* := signl(x)*log1pl(|x| + x^2/(1 + sqrtl(1+x^2)))
*/
#include <float.h>
#include <math.h>
#include <math_private.h>
static const long double
one = 1.0L,
ln2 = 6.931471805599453094172321214581765681e-1L,
huge = 1.0e+4900L;
long double
__asinhl (long double x)
{
long double t, w;
int32_t ix, sign;
ieee854_long_double_shape_type u;
u.value = x;
sign = u.parts32.w0;
ix = sign & 0x7fffffff;
if (ix == 0x7fff0000)
return x + x; /* x is inf or NaN */
if (ix < 0x3fc70000)
{ /* |x| < 2^ -56 */
if (fabsl (x) < LDBL_MIN)
{
long double force_underflow = x * x;
math_force_eval (force_underflow);
}
if (huge + x > one)
return x; /* return x inexact except 0 */
}
u.parts32.w0 = ix;
if (ix > 0x40350000)
{ /* |x| > 2 ^ 54 */
w = __ieee754_logl (u.value) + ln2;
}
else if (ix >0x40000000)
{ /* 2^ 54 > |x| > 2.0 */
t = u.value;
w = __ieee754_logl (2.0 * t + one / (__ieee754_sqrtl (x * x + one) + t));
}
else
{ /* 2.0 > |x| > 2 ^ -56 */
t = x * x;
w = __log1pl (u.value + t / (one + __ieee754_sqrtl (one + t)));
}
if (sign & 0x80000000)
return -w;
else
return w;
}
weak_alias (__asinhl, asinhl)