| #include <limits.h> | |
| #include "libm.h" | |
| int ilogbf(float x) | |
| { | |
| PRAGMA_STDC_FENV_ACCESS_ON | |
| union {float f; uint32_t i;} u = {x}; | |
| uint32_t i = u.i; | |
| int e = i>>23 & 0xff; | |
| if (!e) { | |
| i <<= 9; | |
| if (i == 0) { | |
| FORCE_EVAL(0/0.0f); | |
| return FP_ILOGB0; | |
| } | |
| /* subnormal x */ | |
| for (e = -0x7f; i>>31 == 0; e--, i<<=1); | |
| return e; | |
| } | |
| if (e == 0xff) { | |
| FORCE_EVAL(0/0.0f); | |
| return i<<9 ? FP_ILOGBNAN : INT_MAX; | |
| } | |
| return e - 0x7f; | |
| } |