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| author | Vladimir Azarov <avm@intermediate-node.net> | 2024-10-01 15:47:05 +0200 |
|---|---|---|
| committer | Vladimir Azarov <avm@intermediate-node.net> | 2024-10-01 15:47:05 +0200 |
| commit | 4abab5ad6c8465a7528ccdd5f49367da05f78bbd (patch) | |
| tree | ebf009bf1376a5a223a915bc27cbbd791a1316bc /src/math/ilogbf.c | |
Initial version
Diffstat (limited to 'src/math/ilogbf.c')
| -rw-r--r-- | src/math/ilogbf.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/src/math/ilogbf.c b/src/math/ilogbf.c new file mode 100644 index 0000000..e23ba20 --- /dev/null +++ b/src/math/ilogbf.c @@ -0,0 +1,26 @@ +#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; +} |