1 files changed, 16 insertions, 0 deletions
diff --git a/src/math/lgamma.c b/src/math/lgamma.c
index 3612c825..3f0799c2 100644
--- a/src/math/lgamma.c
+++ b/src/math/lgamma.c
@@ -1,9 +1,25 @@
 # define TGSOURCE "lgamma.c"
 #include "_tgmath.h"
 #include <math.h>
+#include "fenv.h"
 
 TYPE TGFN(lgamma)(TYPE x)
 {
+	switch (fpclassify(x)) {
+	case FP_ZERO:		feraiseexcept(FE_DIVBYZERO); return INFINITY;
+	case FP_INFINITE:	return INFINITY;
+	default:		break;
+	}
+
+	if (x == 1.0 || x == 2.0) {
+		return 0.0;
+	}
+
+	if (signbit(x)) {
+		feraiseexcept(FE_DIVBYZERO);
+		return INFINITY;
+	}
+
 	return x;
 }