diff --git a/kernel/arm/zscal.c b/kernel/arm/zscal.c
index 833dc8c03..569e2503e 100644
--- a/kernel/arm/zscal.c
+++ b/kernel/arm/zscal.c
@@ -43,19 +43,39 @@ int CNAME(BLASLONG n, BLASLONG dummy0, BLASLONG dummy1, FLOAT da_r,FLOAT da_i, F
 	BLASLONG ip = 0;
 	FLOAT temp;
 
-	if ( n < 0 || inc_x < 1     )  return(0);
-
 	inc_x2 = 2 * inc_x;
 	for ( i=0; i<n; i++ )
 	{
-
-		temp    = da_r * x[ip]   - da_i * x[ip+1] ;
-		x[ip+1] = da_r * x[ip+1] + da_i * x[ip]   ;
+		if ( da_r == 0.0 )
+		{
+			if ( da_i == 0.0 )
+			{
+				temp = 0.0;
+				x[ip+1] = 0.0 ;
+			}
+			else
+			{
+				temp = - da_i * x[ip+1] ;
+				x[ip+1] = da_i * x[ip]  ;
+			}
+		}
+		else
+		{
+			if ( da_i == 0.0 )
+			{
+				temp    = da_r * x[ip]  ;
+				x[ip+1] = da_r * x[ip+1];
+			}
+			else
+			{
+				temp    = da_r * x[ip]   - da_i * x[ip+1] ;
+				x[ip+1] = da_r * x[ip+1] + da_i * x[ip]   ;
+			}
+		}
 		x[ip]   = temp;
 
 		ip += inc_x2;
 	}
-	
 
 	return(0);