diff options
| author | Ian Moffett <ian@osmora.org> | 2025-07-14 22:39:34 -0400 |
|---|---|---|
| committer | Ian Moffett <ian@osmora.org> | 2025-07-14 23:27:58 -0400 |
| commit | 30634165980deaeead9f4e71e0ff6a5c9d897776 (patch) | |
| tree | 18546a9d493a699eb3ea23ab5cc792d40cf82d7d /lib/libc/src/musl-math/ilogb.c | |
| parent | 83acdbef7ae961c2ae296835df3f368573c89eeb (diff) | |
usr: libc: Add math.h + musl math impl portexpt
Signed-off-by: Ian Moffett <ian@osmora.org>
Diffstat (limited to 'lib/libc/src/musl-math/ilogb.c')
| -rw-r--r-- | lib/libc/src/musl-math/ilogb.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/lib/libc/src/musl-math/ilogb.c b/lib/libc/src/musl-math/ilogb.c new file mode 100644 index 0000000..64d4015 --- /dev/null +++ b/lib/libc/src/musl-math/ilogb.c @@ -0,0 +1,26 @@ +#include <limits.h> +#include "libm.h" + +int ilogb(double x) +{ + #pragma STDC FENV_ACCESS ON + union {double f; uint64_t i;} u = {x}; + uint64_t i = u.i; + int e = i>>52 & 0x7ff; + + if (!e) { + i <<= 12; + if (i == 0) { + FORCE_EVAL(0/0.0f); + return FP_ILOGB0; + } + /* subnormal x */ + for (e = -0x3ff; i>>63 == 0; e--, i<<=1); + return e; + } + if (e == 0x7ff) { + FORCE_EVAL(0/0.0f); + return i<<12 ? FP_ILOGBNAN : INT_MAX; + } + return e - 0x3ff; +} |