diff options
Diffstat (limited to 'sysdeps/ieee754/ldbl-128ibm/s_erfl.c')
| -rw-r--r-- | sysdeps/ieee754/ldbl-128ibm/s_erfl.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_erfl.c b/sysdeps/ieee754/ldbl-128ibm/s_erfl.c index 95dc415845..f55e8b7879 100644 --- a/sysdeps/ieee754/ldbl-128ibm/s_erfl.c +++ b/sysdeps/ieee754/ldbl-128ibm/s_erfl.c @@ -102,6 +102,7 @@ */ #include <errno.h> +#include <float.h> #include <math.h> #include <math_private.h> #include <math_ldbl_opt.h> @@ -149,9 +150,7 @@ tiny = 1e-300L, one = 1.0L, two = 2.0L, /* 2/sqrt(pi) - 1 */ - efx = 1.2837916709551257389615890312154517168810E-1L, - /* 8 * (2/sqrt(pi) - 1) */ - efx8 = 1.0270333367641005911692712249723613735048E0L; + efx = 1.2837916709551257389615890312154517168810E-1L; /* erf(x) = x + x R(x^2) @@ -801,10 +800,17 @@ __erfl (long double x) if (ix < 0x00800000) { /* erf (-0) = -0. Unfortunately, for IBM extended double - 0.125 * (8.0 * x + efx8 * x) for x = -0 evaluates to 0. */ + 0.0625 * (16.0 * x + (16.0 * efx) * x) for x = -0 + evaluates to 0. */ if (x == 0) return x; - return 0.125 * (8.0 * x + efx8 * x); /*avoid underflow */ + long double ret = 0.0625 * (16.0 * x + (16.0 * efx) * x); + if (fabsl (ret) < LDBL_MIN) + { + long double force_underflow = ret * ret; + math_force_eval (force_underflow); + } + return ret; } return x + efx * x; } |