glibc/sysdeps/ieee754/dbl-64/e_sinh.c
Joseph Myers 5e29dd5737 Fix sinh missing underflows (bug 16519).
Similar to various other bugs in this area, some sinh 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, mips64 and powerpc.

	[BZ #16519]
	* sysdeps/ieee754/dbl-64/e_sinh.c: Include <float.h>.
	(__ieee754_sinh): Force underflow exception for arguments with
	small absolute value.
	* sysdeps/ieee754/flt-32/e_sinhf.c: Include <float.h>.
	(__ieee754_sinhf): Force underflow exception for arguments with
	small absolute value.
	* sysdeps/ieee754/ldbl-128/e_sinhl.c: Include <float.h>.
	(__ieee754_sinhl): Force underflow exception for arguments with
	small absolute value.
	* sysdeps/ieee754/ldbl-128ibm/e_sinhl.c: Include <float.h>.
	(__ieee754_sinhl): Force underflow exception for arguments with
	small absolute value.
	* sysdeps/ieee754/ldbl-96/e_sinhl.c: Include <float.h>.
	(__ieee754_sinhl): Force underflow exception for arguments with
	small absolute value.
	* math/auto-libm-test-in: Add more tests of sinh.
	* math/auto-libm-test-out: Regenerated.
	* sysdeps/i386/fpu/libm-test-ulps: Update.
2015-08-06 23:01:09 +00:00

95 lines
2.4 KiB
C

/* @(#)e_sinh.c 5.1 93/09/24 */
/*
* ====================================================
* 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: e_sinh.c,v 1.7 1995/05/10 20:46:13 jtc Exp $";
#endif
/* __ieee754_sinh(x)
* Method :
* mathematically sinh(x) if defined to be (exp(x)-exp(-x))/2
* 1. Replace x by |x| (sinh(-x) = -sinh(x)).
* 2.
* E + E/(E+1)
* 0 <= x <= 22 : sinh(x) := --------------, E=expm1(x)
* 2
*
* 22 <= x <= lnovft : sinh(x) := exp(x)/2
* lnovft <= x <= ln2ovft: sinh(x) := exp(x/2)/2 * exp(x/2)
* ln2ovft < x : sinh(x) := x*shuge (overflow)
*
* Special cases:
* sinh(x) is |x| if x is +INF, -INF, or NaN.
* only sinh(0)=0 is exact for finite x.
*/
#include <float.h>
#include <math.h>
#include <math_private.h>
static const double one = 1.0, shuge = 1.0e307;
double
__ieee754_sinh (double x)
{
double t, w, h;
int32_t ix, jx;
u_int32_t lx;
/* High word of |x|. */
GET_HIGH_WORD (jx, x);
ix = jx & 0x7fffffff;
/* x is INF or NaN */
if (__glibc_unlikely (ix >= 0x7ff00000))
return x + x;
h = 0.5;
if (jx < 0)
h = -h;
/* |x| in [0,22], return sign(x)*0.5*(E+E/(E+1))) */
if (ix < 0x40360000) /* |x|<22 */
{
if (__glibc_unlikely (ix < 0x3e300000)) { /* |x|<2**-28 */
if (fabs (x) < DBL_MIN)
{
double force_underflow = x * x;
math_force_eval (force_underflow);
}
if (shuge + x > one)
return x;
/* sinh(tiny) = tiny with inexact */
}
t = __expm1 (fabs (x));
if (ix < 0x3ff00000)
return h * (2.0 * t - t * t / (t + one));
return h * (t + t / (t + one));
}
/* |x| in [22, log(maxdouble)] return 0.5*exp(|x|) */
if (ix < 0x40862e42)
return h * __ieee754_exp (fabs (x));
/* |x| in [log(maxdouble), overflowthresold] */
GET_LOW_WORD (lx, x);
if (ix < 0x408633ce || ((ix == 0x408633ce) && (lx <= (u_int32_t) 0x8fb9f87d)))
{
w = __ieee754_exp (0.5 * fabs (x));
t = h * w;
return t * w;
}
/* |x| > overflowthresold, sinh(x) overflow */
return x * shuge;
}
strong_alias (__ieee754_sinh, __sinh_finite)