alttpr-gwaa-kiwi/alttpr-python
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Tested a lot of north edges

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aerinon
2020-02-19 12:50:37 -07:00
parent b76a5f954d
commit 6f3040415d
5 changed files with 202 additions and 61 deletions
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asm/math.asm Normal file
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;divide by 2 example
; 0 1 2 3 4 5 6 7 8 9 a b c d e f 10--Offset Ruler
;v 00 01 01 02 02 03 03 04 04 04 05 05 06 06 07 07 08
;divide by 3 example
; 0 1 2 3 4 5 6 7 8 9 a b c d e f 10 11 12 13 14 15 16 17 18
;00 00 01 01 01 02 02 02 03 03 03 04 04 04 05 05 05 06 06 06 07 07 07 08 08
MultiplyByY:
.loop cpy #$0001 : beq .done
cpy #$0003 : bne ++
jsr MultiBy3 : bra .done
++ cpy #$0005 : bne ++
jsr MultiBy5 : bra .done
++ asl : sta $00 : tya : lsr : tay : lda $00 : bra .loop
.done rts
;todo -- width in X?
DivideByY:
.loop cpy #$0001 : beq .done
cpy #$0003 : bne ++
jsr DivideBy3 : bra .done
++ cpy #$0005 : bne ++
jsr DivideBy5 : bra .done
; todo -- alter - width
++ tyx : jsr DivideBy2 : sta $00 : tya : lsr : tay : lda $00 : bra .loop
.done rts
MultiBy3:
sta $00 : asl : !add $00
rts
MultiBy5:
sta $00 : asl #2 : !add $00
rts
;width of divison in x
DivideBy2:
sta $00
lsr : bcc .done
sta $02 : txa : lsr : cmp $00 : !bge .done
lda $02 : inc
.done rts
DivideBy3:
sta $00
ldx #$0000
lda #$0002
.loop cmp $00 : !bge .store
inx : !add #$0003 : bra .loop
.store txa
rts
DivideBy5:
sta $00
ldx #$0000
lda #$0003
.loop cmp $00 : !bge .store
inx : !add #$0005 : bra .loop
.store txa
rts