diff --git a/kernel/zarch/zscal.c b/kernel/zarch/zscal.c
index eebae44c5..36466a6e0 100644
--- a/kernel/zarch/zscal.c
+++ b/kernel/zarch/zscal.c
@@ -381,7 +381,7 @@ int CNAME(BLASLONG n, BLASLONG dummy0, BLASLONG dummy1, FLOAT da_r, FLOAT da_i,
         	x[i + 1] = da_i * x[i];
 	else
 		x[i + 1] = NAN;
-	if (isfinite(x[i]))
+	if (x[i]==x[i])
           x[i] = temp0;
         i += 2;
         j++;