clear screen and both hi-res pages before launching

src/glue.launch.a

@@ -134,12 +134,25 @@ gCurrentlyVisibleSlideshowIndex
 .Go
 ; in:    A/Y = lo/hi address of filename
          +STAY SAVE
+         +STAY +
+         +STAY @pfile
+
+         jsr   Home                  ; clear screen (clobbers $106, must do now before loading prelaunch code)
+         lda   #$20                  ; clear both hi-res pages
+         sta   @clear+2              ; (in case game loader shows them, we don't want
+         ldx   #$40                  ; to flash previous bits of the launcher UI)
+         ldy   #$00
+         tya
+@clear   sta   $FD00,y
+         iny
+         bne   @clear
+         inc   @clear+2
+         dex
+         bne   @clear
 
          bit   gCheatsEnabled        ; are cheats enabled?
          bpl   @noCheats
 
-         +STAY +
-         +STAY @pfile
          jsr   okvs_get              ; need to get game index from filename to determine
          !word gGamesListStore       ; whether there are any cheats for this game
 +        !word $FDFD                 ; SMC