[stella] 6 Digit Code Frustrations

["Chris Larkin" <clarkin@xxxxxxxxxxxxx>]

I'm trying to set up a 48 pixel sprite that rolls colors, examples include Thrust's title screen, Raiders of The Lost Ark, "Ark" and so on...

 

The only code I can find on the 6 digit technique uses this code to draw the sprite.  Is it just me? Where can I put in a change to both player's color registers before the next scan line is drawn using this kernal.  Any help would be greatly appreciated...

 

I think sample title screen code would be a much needed addition to the Archives as well.

 

mainloop

        ldy count1   ;3
         lda (ptr0),y ;5
         sta GRP0     ;3 = 11
        ; sta WSYNC    ;3 =  3
         bit $00

 

         lda (ptr1),y ;5
         sta GRP1     ;3
         lda (ptr5),y ;5
         tax          ;2
         txs          ;2
         lda (ptr2),y ;5
         sta tmp      ;3
         lda (ptr3),y ;5
         tax          ;2
         lda (ptr4),y ;5 = 37

 

         ldy tmp      ;3
         sty GRP0     ;3
         stx GRP1     ;3
         sta GRP0     ;3
         tsx          ;2
         stx GRP1     ;3 = 17

 

         dec count1   ;5
         bpl mainloop ;3 =  8

 

         lda #0
         sta GRP0
         sta GRP1