1 files changed, 2 insertions, 1 deletions
diff --git a/lib/factorial.c b/lib/factorial.c
index 8e64fa3..7e82ffb 100644
--- a/lib/factorial.c
+++ b/lib/factorial.c
@@ -8,6 +8,7 @@
 // Outputs:   1 (n!)
 // Constants: 0
 
+#include <math.h>
 #include "ts.h"
 
 
@@ -31,7 +32,7 @@ int ts_factorial(
 	(void)c;
 	for( uint_t i = 0; i < n; ++i )
 	{
-		if (x[0][i] < 0) { y[0][i] = NAN; continue; }
+		if (isnan(x[0][i]) || isinf(x[0][i]) || x[0][i] < 0) { y[0][i] = NAN; continue; }
 		fp_t result = 1.0;
 		uint_t k = (uint_t)x[0][i];
 		if (k > 170) k = 170;