diff options
Diffstat (limited to 'sysdeps/ieee754/dbl-64/e_gamma_r.c')
| -rw-r--r-- | sysdeps/ieee754/dbl-64/e_gamma_r.c | 87 |
1 files changed, 62 insertions, 25 deletions
diff --git a/sysdeps/ieee754/dbl-64/e_gamma_r.c b/sysdeps/ieee754/dbl-64/e_gamma_r.c index 7a2af31c46..adeb61a248 100644 --- a/sysdeps/ieee754/dbl-64/e_gamma_r.c +++ b/sysdeps/ieee754/dbl-64/e_gamma_r.c @@ -104,7 +104,7 @@ gamma_positive (double x, int *exp2_adj) * __ieee754_exp (-x_adj) * __ieee754_sqrt (2 * M_PI / x_adj) / prod); - exp_adj += x_eps * __ieee754_log (x); + exp_adj += x_eps * __ieee754_log (x_adj); double bsum = gamma_coeff[NCOEFF - 1]; double x_adj2 = x_adj * x_adj; for (size_t i = 1; i <= NCOEFF - 1; i++) @@ -119,6 +119,10 @@ __ieee754_gamma_r (double x, int *signgamp) { int32_t hx; u_int32_t lx; +#if FLT_EVAL_METHOD != 0 + volatile +#endif + double ret; EXTRACT_WORDS (hx, lx, x); @@ -153,36 +157,69 @@ __ieee754_gamma_r (double x, int *signgamp) { /* Overflow. */ *signgamp = 0; - return DBL_MAX * DBL_MAX; + ret = DBL_MAX * DBL_MAX; + return ret; } - else if (x > 0.0) + else { - *signgamp = 0; - int exp2_adj; - double ret = gamma_positive (x, &exp2_adj); - return __scalbn (ret, exp2_adj); + SET_RESTORE_ROUND (FE_TONEAREST); + if (x > 0.0) + { + *signgamp = 0; + int exp2_adj; + double tret = gamma_positive (x, &exp2_adj); + ret = __scalbn (tret, exp2_adj); + } + else if (x >= -DBL_EPSILON / 4.0) + { + *signgamp = 0; + ret = 1.0 / x; + } + else + { + double tx = __trunc (x); + *signgamp = (tx == 2.0 * __trunc (tx / 2.0)) ? -1 : 1; + if (x <= -184.0) + /* Underflow. */ + ret = DBL_MIN * DBL_MIN; + else + { + double frac = tx - x; + if (frac > 0.5) + frac = 1.0 - frac; + double sinpix = (frac <= 0.25 + ? __sin (M_PI * frac) + : __cos (M_PI * (0.5 - frac))); + int exp2_adj; + double tret = M_PI / (-x * sinpix + * gamma_positive (-x, &exp2_adj)); + ret = __scalbn (tret, -exp2_adj); + } + } } - else if (x >= -DBL_EPSILON / 4.0) + if (isinf (ret) && x != 0) { - *signgamp = 0; - return 1.0 / x; + if (*signgamp < 0) + { + ret = -__copysign (DBL_MAX, ret) * DBL_MAX; + ret = -ret; + } + else + ret = __copysign (DBL_MAX, ret) * DBL_MAX; + return ret; } - else + else if (ret == 0) { - double tx = __trunc (x); - *signgamp = (tx == 2.0 * __trunc (tx / 2.0)) ? -1 : 1; - if (x <= -184.0) - /* Underflow. */ - return DBL_MIN * DBL_MIN; - double frac = tx - x; - if (frac > 0.5) - frac = 1.0 - frac; - double sinpix = (frac <= 0.25 - ? __sin (M_PI * frac) - : __cos (M_PI * (0.5 - frac))); - int exp2_adj; - double ret = M_PI / (-x * sinpix * gamma_positive (-x, &exp2_adj)); - return __scalbn (ret, -exp2_adj); + if (*signgamp < 0) + { + ret = -__copysign (DBL_MIN, ret) * DBL_MIN; + ret = -ret; + } + else + ret = __copysign (DBL_MIN, ret) * DBL_MIN; + return ret; } + else + return ret; } strong_alias (__ieee754_gamma_r, __gamma_r_finite) |