lda $00
pha

; Use half the coins as the limit.
lda #$64
sec
sbc $dbf

; Is Mario moving positive or negative?
bit $7b
bpl positive

; Negative. Invert the limit.
eor #$ff
sta $00

; If the speed is faster (smaller) than the limit, cap it.
lda $7b
cmp $00
bcs done
bcc cap

positive:
sta $00
lda $7b
cmp $00
bcc done

cap:
lda $00
sta $7b

done:
pla
sta $00
rtl

back to listings