usr: libc: Add math.h + musl math impl port

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/lib/libc/src/musl-math/__signbitl.c b/lib/libc/src/musl-math/__signbitl.c
new file mode 100644
index 0000000..63b3dc5
--- /dev/null
+++ b/lib/libc/src/musl-math/__signbitl.c
@@ -0,0 +1,14 @@
+#include "libm.h"
+
+#if (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
+int __signbitl(long double x)
+{
+	union ldshape u = {x};
+	return u.i.se >> 15;
+}
+#elif LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+int __signbitl(long double x)
+{
+	return __signbit(x);
+}
+#endif