1 files changed, 57 insertions, 1 deletions
diff --git a/src/complex/ctanh.c b/src/complex/ctanh.c
index cf203dd5..c787e5ba 100644
--- a/src/complex/ctanh.c
+++ b/src/complex/ctanh.c
@@ -1,10 +1,66 @@
 # define TGSOURCE "../complex/ctanh.c"
 #include "_tgmath.h"
-
 #include <complex.h>
+#include "math.h"
+#include "fenv.h"
 
 TYPE complex TGFN(ctanh)(TYPE complex z)
 {
+	int classr = fpclassify(TGFN(creal)(z));
+	int classi = fpclassify(TGFN(cimag)(z));
+	//int signr = signbit(TGFN(creal)(z));
+	int signi = signbit(TGFN(cimag)(z));
+
+	if (classr == FP_ZERO && classi == FP_ZERO) {
+		return TGCMPLX(0.0, 0.0);
+	}
+
+	if (classr == FP_ZERO && classi == FP_INFINITE) {
+		feraiseexcept(FE_INVALID);
+		return TGCMPLX(0.0, NAN);
+	}
+
+	if (classr != FP_INFINITE && classr != FP_ZERO && classi == FP_INFINITE) {
+		feraiseexcept(FE_INVALID);
+		return TGCMPLX(NAN, NAN);
+	}
+
+	if (classr == FP_ZERO && classi == FP_NAN) {
+		return TGCMPLX(0.0, NAN);
+	}
+
+	if (classr != FP_INFINITE && classr != FP_ZERO && classi == FP_NAN) {
+		feraiseexcept(FE_INVALID);
+		return TGCMPLX(NAN, NAN);
+	}
+
+	if (classr == FP_INFINITE && classi != FP_INFINITE && !signi) {
+		TYPE y = TGFN(cimag)(z);
+		/* FIXME: this is surely a typo in C18 */
+		return TGCMPLX(1.0, 0 * TGFN(sin)(2 * y));
+	}
+
+	if (classr == FP_INFINITE && classi == FP_INFINITE) {
+		return TGCMPLX(1.0, 0.0);
+	}
+
+	if (classr == FP_INFINITE && classi == FP_NAN) {
+		return TGCMPLX(1.0, 0.0);
+	}
+
+	if (classr == FP_NAN && classi == FP_ZERO) {
+		return TGCMPLX(NAN, 0.0);
+	}
+
+	if (classr == FP_NAN && classi != FP_INFINITE && classi != FP_ZERO) {
+		feraiseexcept(FE_INVALID);
+		return TGCMPLX(NAN, NAN);
+	}
+
+	if (classr == FP_NAN && classi == FP_NAN) {
+		return TGCMPLX(NAN, NAN);
+	}
+
 	return z;
 }