A examples/lib/lowcase.xyw

@@ -0,0 +1,23 @@ 
+;.include "lib/macros.xyw"
+
+; Convert a string to lowercase 
+; a16 -[xw]-
+.label lowcase
+  ; store index
+  POPxw
+  .label lowcase.loop
+    LDBxw $00 EQU lowcase.end JCNw
+    ; check if an uppercase letter
+    LDBxw $40 GTH
+    LDBxw $5B LTH
+    AND lowcase.change JCNw
+    ; continue
+    INCxw lowcase.loop JMPw
+    .label lowcase.change
+      ; convert to lowercase  
+      LDBxw $20 ADD STBxw
+      ; continue 
+      INCxw lowcase.loop JMPw
+    .label lowcase.end
+      RTS
+