--- /dev/null
+#include "libm.h"
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+long double complex casinl(long double complex z)
+{
+ return casin(z);
+}
+#else
+// FIXME
+long double complex casinl(long double complex z)
+{
+ long double complex w;
+ long double x, y;
+
+ x = creall(z);
+ y = cimagl(z);
+ w = cpackl(1.0 - (x - y)*(x + y), -2.0*x*y);
+ return clogl(cpackl(-y, x) + csqrtl(w));
+}
+#endif