diff --git a/YAOCMouse.ino b/YAOCMouse.ino
index a6f36e4..8bc3950 100644
--- a/YAOCMouse.ino
+++ b/YAOCMouse.ino
@@ -89,7 +89,7 @@ void amigaYpulse(int8_t count) {
     else {
       mouseYTableIndex--;
 
-      if (mouseYTableIndex == -1) {
+      if (mouseYTableIndex < 0) {
         mouseYTableIndex = 3;
       }
     }
@@ -119,7 +119,7 @@ void amigaXpulse(int8_t count) {
     else {
       mouseXTableIndex--;
 
-      if (mouseXTableIndex == -1) {
+      if (mouseXTableIndex < 0) {
         mouseXTableIndex = 3;
       }
     }