diff options
Diffstat (limited to 'math/e_exp2l.c')
| -rw-r--r-- | math/e_exp2l.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/math/e_exp2l.c b/math/e_exp2l.c index bb7feefeff..9eb7bafadd 100644 --- a/math/e_exp2l.c +++ b/math/e_exp2l.c @@ -20,6 +20,13 @@ #include <math_private.h> #include <float.h> +/* To avoid spurious underflows, use this definition to treat IBM long + double as approximating an IEEE-style format. */ +#if LDBL_MANT_DIG == 106 +# undef LDBL_EPSILON +# define LDBL_EPSILON 0x1p-106L +#endif + long double __ieee754_exp2l (long double x) { @@ -31,6 +38,8 @@ __ieee754_exp2l (long double x) { int intx = (int) x; long double fractx = x - intx; + if (fabsl (fractx) < LDBL_EPSILON / 4.0L) + return __scalbnl (1.0L + fractx, intx); return __scalbnl (__ieee754_expl (M_LN2l * fractx), intx); } else |