diff options
Diffstat (limited to 'src/math/exp.c')
| -rw-r--r-- | src/math/exp.c | 21 |
1 files changed, 10 insertions, 11 deletions
diff --git a/src/math/exp.c b/src/math/exp.c index 5ec8f8a7..2b182acd 100644 --- a/src/math/exp.c +++ b/src/math/exp.c @@ -80,7 +80,7 @@ P5 = 4.13813679705723846039e-08; /* 0x3E663769, 0x72BEA4D0 */ double exp(double x) { - double hi, lo, c, xx; + double_t hi, lo, c, xx, y; int k, sign; uint32_t hx; @@ -89,20 +89,19 @@ double exp(double x) hx &= 0x7fffffff; /* high word of |x| */ /* special cases */ - if (hx >= 0x40862e42) { /* if |x| >= 709.78... */ + if (hx >= 0x4086232b) { /* if |x| >= 708.39... */ if (isnan(x)) return x; - if (hx == 0x7ff00000 && sign) /* -inf */ - return 0; if (x > 709.782712893383973096) { /* overflow if x!=inf */ STRICT_ASSIGN(double, x, 0x1p1023 * x); return x; } - if (x < -745.13321910194110842) { - /* underflow */ - STRICT_ASSIGN(double, x, 0x1p-1000 * 0x1p-1000); - return x; + if (x < -708.39641853226410622) { + /* underflow if x!=-inf */ + FORCE_EVAL((float)(-0x1p-149/x)); + if (x < -745.13321910194110842) + return 0; } } @@ -128,8 +127,8 @@ double exp(double x) /* x is now in primary range */ xx = x*x; c = x - xx*(P1+xx*(P2+xx*(P3+xx*(P4+xx*P5)))); - x = 1 + (x*c/(2-c) - lo + hi); + y = 1 + (x*c/(2-c) - lo + hi); if (k == 0) - return x; - return scalbn(x, k); + return y; + return scalbn(y, k); } |