| 1 | #include <math.h> |
| 2 | #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024 |
| 3 | long double logbl(long double x) |
| 4 | { |
| 5 | return logb(x); |
| 6 | } |
| 7 | #else |
| 8 | long double logbl(long double x) |
| 9 | { |
| 10 | if (!isfinite(x)) |
| 11 | return x * x; |
| 12 | if (x == 0) |
| 13 | return -1/(x*x); |
| 14 | return ilogbl(x); |
| 15 | } |
| 16 | #endif |