partly producing output

dither4.s

@@ -52,7 +52,7 @@ displaylist:
     sta COLPF0
     stx COLPF1
     sty COLPF2
-    rst
+    rts
 .endproc
 
 .proc start
@@ -60,9 +60,9 @@ displaylist:
     lda #$00
     sta SDMCTL
     ; Set up the display list
-    lda .low displaylist
+    lda #.lobyte(displaylist)
     sta SDLSTL
-    lda .high displaylist
+    lda #.hibyte(displaylist)
     sta SDLSTH
 
     ; Turn off interrupts except reset button
@@ -72,7 +72,7 @@ displaylist:
     ; Manually wait for first scan line
 wait_vblank:
     lda VCOUNT
-    bnz wait_vblank
+    bne wait_vblank
 
     ; Re-enable display DMA
     lda #$22