--- /dev/null
+#include "libm.h"
+
+// FIXME
+
+float complex casinf(float complex z)
+{
+ float complex w;
+ float x, y;
+
+ x = crealf(z);
+ y = cimagf(z);
+ w = cpackf(1.0 - (x - y)*(x + y), -2.0*x*y);
+ return clogf(cpackf(-y, x) + csqrtf(w));
+}