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

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

1 files changed, 20 insertions, 0 deletions

diff --git a/lib/libc/src/musl-math/nearbyint.c b/lib/libc/src/musl-math/nearbyint.c
new file mode 100644
index 0000000..f4e8aac
--- /dev/null
+++ b/lib/libc/src/musl-math/nearbyint.c
@@ -0,0 +1,20 @@
+#include <fenv.h>
+#include <math.h>
+
+/* nearbyint is the same as rint, but it must not raise the inexact exception */
+
+double nearbyint(double x)
+{
+#ifdef FE_INEXACT
+	#pragma STDC FENV_ACCESS ON
+	int e;
+
+	e = fetestexcept(FE_INEXACT);
+#endif
+	x = rint(x);
+#ifdef FE_INEXACT
+	if (!e)
+		feclearexcept(FE_INEXACT);
+#endif
+	return x;
+}