Merge pull request #2978 from StewBC/plus4-cgetc-bitmap-fix

Fix plus4 cgetc() returning a phantom key in bitmap mode

libsrc/plus4/cgetc.s

@@ -18,16 +18,20 @@ _cgetc: lda     KEY_COUNT       ; Get number of characters
         ora     FKEY_COUNT      ; Or with number of function key chars
         bne     L2              ; Jump if there are already chars waiting
 
-        lda     #%00100000
-        bit     $FF06
-        bne     L2              ; always disable cursor if in bitmap mode
-
-; Switch on the cursor if needed
+; Save the character under the cursor, wait for a key, then put it back.  In
+; bitmap mode there is no cursor to show, so the save and restore are
+; effectively a no-op.
 
         ldy     CURS_X
         lda     (CRAM_PTR),y    ; Get current char
         pha                     ; And save it
 
+        lda     #%00100000
+        bit     $FF06
+        bne     L1              ; No cursor in bitmap mode
+
+; Switch on the cursor if needed
+
         lda     CHARCOLOR
         sta     (CRAM_PTR),y