1 files changed, 10 insertions, 0 deletions
diff --git a/circuitpython/lib/libm_dbl/__signbit.c b/circuitpython/lib/libm_dbl/__signbit.c
new file mode 100644
index 0000000..f1f1ae8
--- /dev/null
+++ b/circuitpython/lib/libm_dbl/__signbit.c
@@ -0,0 +1,10 @@
+#include "libm.h"
+
+int __signbitd(double x)
+{
+	union {
+		double d;
+		uint64_t i;
+	} y = { x };
+	return y.i>>63;
+}