diff --git a/mach/proto/fp/ngf4.c b/mach/proto/fp/ngf4.c
index 7b2351f64..540b1f1fe 100644
--- a/mach/proto/fp/ngf4.c
+++ b/mach/proto/fp/ngf4.c
@@ -21,7 +21,9 @@ _float	f;
 {
 	char unsigned	*p;
 
-	p = (char unsigned *) &f;
-	*p ^= 0x80;
+	if (f != (_float) 0) {
+		p = (char unsigned *) &f;
+		*p ^= 0x80;
+	}
 }
 
diff --git a/mach/proto/fp/ngf8.c b/mach/proto/fp/ngf8.c
index 178a9b763..b36a53c7a 100644
--- a/mach/proto/fp/ngf8.c
+++ b/mach/proto/fp/ngf8.c
@@ -21,7 +21,9 @@ _double	f;
 {
 	unsigned char	*p;
 
-	p = (unsigned char *) &f;
-	*p ^= 0x80;
+	if (f[0] != 0 || f[1] != 0) {
+		p = (unsigned char *) &f;
+		*p ^= 0x80;
+	}
 }