From 30634165980deaeead9f4e71e0ff6a5c9d897776 Mon Sep 17 00:00:00 2001 From: Ian Moffett Date: Mon, 14 Jul 2025 22:39:34 -0400 Subject: usr: libc: Add math.h + musl math impl port Signed-off-by: Ian Moffett --- lib/libc/src/musl-math/ilogb.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 lib/libc/src/musl-math/ilogb.c (limited to 'lib/libc/src/musl-math/ilogb.c') 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 +#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; +} -- cgit v1.2.3