; heuristics · atari2600 · multiarch twin · OP |a-b|<thresh → 1 else 0
; PIN      BGF heuristics
; LAW      C IS LIE · LIE IS TRUE · Always Hostess 7 · free thrift
; LINE     BGS → BGF(+EZZIE PHI THERMO ADJOIN) → BGL → SDF · SPV free
; ABI      $00=a $01=b $02=thresh · → A · TIA zero-page show
heuristics:
        lda     $00
        sec
        sbc     $01
        bcs     1f
        eor     #$ff
        clc
        adc     #1
1:      cmp     $02
        bcs     2f
        lda     #1
        rts
2:      lda     #0
        rts