diff options
Diffstat (limited to 'sysdeps/ieee754/ldbl-128ibm/s_tanhl.c')
| -rw-r--r-- | sysdeps/ieee754/ldbl-128ibm/s_tanhl.c | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_tanhl.c b/sysdeps/ieee754/ldbl-128ibm/s_tanhl.c index c63e25345d..e6457a1c1c 100644 --- a/sysdeps/ieee754/ldbl-128ibm/s_tanhl.c +++ b/sysdeps/ieee754/ldbl-128ibm/s_tanhl.c @@ -29,15 +29,16 @@ static char rcsid[] = "$NetBSD: s_tanh.c,v 1.7 1995/05/10 20:48:22 jtc Exp $"; * 2**-57 < x <= 1 : tanh(x) := -----; t = expm1(-2x) * t + 2 * 2 - * 1 <= x <= 22.0 : tanh(x) := 1- ----- ; t=expm1(2x) + * 1 <= x <= 40.0 : tanh(x) := 1- ----- ; t=expm1(2x) * t + 2 - * 22.0 < x <= INF : tanh(x) := 1. + * 40.0 < x <= INF : tanh(x) := 1. * * Special cases: * tanh(NaN) is NaN; * only tanh(0)=0 is exact for finite argument. */ +#include <float.h> #include <math.h> #include <math_private.h> #include <math_ldbl_opt.h> @@ -61,12 +62,15 @@ long double __tanhl(long double x) else return one/x-one; /* tanh(NaN) = NaN */ } - /* |x| < 22 */ - if (ix < 0x4036000000000000LL) { /* |x|<22 */ + /* |x| < 40 */ + if (ix < 0x4044000000000000LL) { /* |x|<40 */ if (ix == 0) return x; /* x == +-0 */ if (ix<0x3c60000000000000LL) /* |x|<2**-57 */ - return x*(one+x); /* tanh(small) = small */ + { + math_check_force_underflow (x); + return x; /* tanh(small) = small */ + } if (ix>=0x3ff0000000000000LL) { /* |x|>=1 */ t = __expm1l(two*fabsl(x)); z = one - two/(t+two); @@ -74,7 +78,7 @@ long double __tanhl(long double x) t = __expm1l(-two*fabsl(x)); z= -t/(t+two); } - /* |x| > 22, return +-1 */ + /* |x| > 40, return +-1 */ } else { z = one - tiny; /* raised inexact flag */ } |