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

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

1 files changed, 10 insertions, 0 deletions

diff --git a/lib/libc/src/musl-math/copysignf.c b/lib/libc/src/musl-math/copysignf.c
new file mode 100644
index 0000000..0af6ae9
--- /dev/null
+++ b/lib/libc/src/musl-math/copysignf.c
@@ -0,0 +1,10 @@
+#include <math.h>
+#include <stdint.h>
+
+float copysignf(float x, float y)
+{
+	union {float f; uint32_t i;} ux={x}, uy={y};
+	ux.i &= 0x7fffffff;
+	ux.i |= uy.i & 0x80000000;
+	return ux.f;
+}