Re: [stella] How RRampage works

Subject: Re: [stella] How RRampage works
From: Thomas Jentzsch <tjentzsch@xxxxxx>
Date: Mon, 12 Apr 2004 22:58:06 +0200
Erik Mooney wrote:
>If you find it necessary to recover the ROM space, Thomas's
>SkipDraw routine is the fastest way to draw a static object like
>your ball.

Skipdraw is meant for player objects. For particle objects like 
missiles or the ball this code is better:

  tya                 ; 2 assuming y contains the scanline
  sbc yPos            ; 3 carry must be 1 (else use DCP)
  adc #HEIGHT         ; 2
  lda	#2		    ; 2
  adc #$ff            ; 2 carry is always set!
  sta ENAMx/BL        ; 3 bit 1 depends on the carry after ADC
; total: 14 cycles

Have fun!	

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