; reading driving controllers, by Thomas Jentzsch

  	lda SWCHA
  	tay
  	eor last	; 01 or 10 (else: abrupt twist)
  	sty last
  	dey		; -> y = -1..2
  	cpy  #2	
  	sbc  #1	; -> a = -1, 0, 1
  	beq .right
.left: