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

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

1 files changed, 27 insertions, 0 deletions

diff --git a/lib/libc/src/musl-math/floorf.c b/lib/libc/src/musl-math/floorf.c
new file mode 100644
index 0000000..dceec73
--- /dev/null
+++ b/lib/libc/src/musl-math/floorf.c
@@ -0,0 +1,27 @@
+#include "libm.h"
+
+float floorf(float x)
+{
+	union {float f; uint32_t i;} u = {x};
+	int e = (int)(u.i >> 23 & 0xff) - 0x7f;
+	uint32_t m;
+
+	if (e >= 23)
+		return x;
+	if (e >= 0) {
+		m = 0x007fffff >> e;
+		if ((u.i & m) == 0)
+			return x;
+		FORCE_EVAL(x + 0x1p120f);
+		if (u.i >> 31)
+			u.i += m;
+		u.i &= ~m;
+	} else {
+		FORCE_EVAL(x + 0x1p120f);
+		if (u.i >> 31 == 0)
+			u.i = 0;
+		else if (u.i << 1)
+			u.f = -1.0;
+	}
+	return u.f;
+}