diff --git a/src/test/kc/comparison-rewriting.kc b/src/test/kc/comparison-rewriting.kc
index 74c9deec5..a8ad8885b 100644
--- a/src/test/kc/comparison-rewriting.kc
+++ b/src/test/kc/comparison-rewriting.kc
@@ -1,13 +1,15 @@
 // Test rewriting of constant comparisons
 
 void main() {
-    byte* screen = $0400;
+    const byte* SCREEN = $0400;
 
-    for(byte* sc : screen..screen+1000) *sc=' ';
+    for(byte* sc : SCREEN..SCREEN+1000) *sc=' ';
 
     byte[] header = "  <  <= == >= >";
     for( byte i=0; header[i]!=0; i++)
-        screen[i] = header[i];
+        SCREEN[i] = header[i];
+
+    byte* screen = SCREEN;
 
     for(byte i=0;i<=9;i++) {
         screen +=40;