292 lines
7.6 KiB
NASM
292 lines
7.6 KiB
NASM
HorzEdge:
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cpy #$ff : beq +
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jsr DetectWestEdge : bra ++
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+ jsr DetectEastEdge
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++ cmp #$ff : beq +
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sta $00 : asl : !add $00 : tax
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cpy #$ff : beq ++
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jsr LoadWestData : bra .main
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++ jsr LoadEastData
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.main
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jsr LoadEdgeRoomHorz
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sec : rts
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+ clc : rts
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VertEdge:
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cpy #$ff : beq +
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jsr DetectNorthEdge : bra ++
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+ jsr DetectSouthEdge
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++ cmp #$ff : beq +
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sta $00 : asl : !add $00 : tax
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cpy #$ff : beq ++
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jsr LoadNorthData : bra .main
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++ jsr LoadSouthData
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.main
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jsr LoadEdgeRoomVert
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sec : rts
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+ clc : rts
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LoadEdgeRoomHorz:
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lda $03 : sta $a0
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sty $09
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and.b #$0f : asl a : !sub $23 : !add $09 : sta $02
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ldy #$00 : jsr ShiftVariablesMainDir
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lda $a0 : and.b #$F0 : lsr #3 : sta $0603 : inc : sta $0607
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lda $aa : asl : tax ; current quad as 0/4
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lda $04 : and #$40 : bne +
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lda $603 : sta $00 : stz $01 : bra ++
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+ lda $607 : sta $00 : lda #$02 : sta $01
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++ ; $01 now contains 0 or 2
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lda $00 : sta $21 : sta $0601 : sta $0605
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lda $01 : sta $aa : lsr : sta $01 : stz $00
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lda $0a : sta $20
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stz $0e
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rep #$30
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lda $e8 : and #$01ff : sta $02
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lda $0a : and #$00ff : !add $00 : sta $00
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cmp #$006c : !bge +
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lda #$0077 : bra ++
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+ cmp #$017c : !blt +
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lda #$0187 : bra ++
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+ !add #$000b
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++ sta $0618 : inc #2 : sta $061a
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lda $00 : cmp #$0078 : !bge +
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lda #$0000 : bra ++
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+ cmp #$0178 : !blt +
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lda #$0100 : bra ++
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+ !sub #$0078
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++ sta $00
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; figures out scroll amt
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cmp $02 : bne +
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lda #$0000 : bra .done
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+ !blt +
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!sub $02 : inc $0e : bra .done
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+ lda $02 : !sub $00
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.done sta $ab : sep #$30
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lda $0e : asl : ora $ac : sta $ac
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lda $0603, x : sta $e9
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lda $04 : and #$80 : lsr #4 : sta $ee ; layer stuff
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rts
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LoadEdgeRoomVert:
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lda $03 : sta $a0
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sty $09
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and.b #$f0 : lsr #3 : !sub $21 : !add $09 : sta $02
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ldy #$01 : jsr ShiftVariablesMainDir
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lda $a0 : and.b #$0f : asl : sta $060b : inc : sta $060f
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lda $a9 : asl #2 : tax ; current quad as 0/4
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lda $04 : and #$20 : bne +
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lda $60b : sta $00 : stz $01 : bra ++
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+ lda $60f : sta $00 : lda #$01 : sta $01
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++ ; $01 now contains 0 or 1
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lda $00 : sta $23 : sta $0609 : sta $060d
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lda $01 : sta $a9 : stz $00 ; setup for 16 bit ops
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lda $0a : sta $22
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stz $0e ; pos/neg indicator
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rep #$30
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lda $e2 : and #$01ff : sta $02
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lda $0a : and #$00ff : !add $00 : sta $00
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cmp #$0078 : !bge +
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lda #$007f : bra ++
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+ cmp #$0178 : !blt +
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lda #$017f : bra ++
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+ !add #$0007
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++ sta $061c : inc #2 : sta $061e
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lda $00 : cmp #$0078 : !bge +
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lda #$0000 : bra ++
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+ cmp #$0178 : !blt +
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lda #$0100 : bra ++
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+ !sub #$0078
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++ sta $00
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; figures out scroll amt
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cmp $02 : bne +
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lda #$0000 : bra .done
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+ !blt +
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!sub $02 : inc $0e : bra .done
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+ lda $02 : !sub $00
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.done sta $ab : sep #$30
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lda $0e : asl : ora $ac : sta $ac
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lda $060b, x : sta $e3
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lda $04 : and #$10 : lsr #4 : sta $ee ; layer stuff
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rts
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LoadNorthData:
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lda NorthEdgeInfo, x : sta $06 ; not needed I think
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lda NorthOpenEdge, x : sta $03 : inx
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lda NorthEdgeInfo, x : sta $07 ;probably needed for maths - unsure
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lda NorthOpenEdge, x : sta $04 : inx
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lda NorthEdgeInfo, x : sta $08 ; needed for maths
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lda NorthOpenEdge, x : sta $05
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lda $04 : and #$0f : sta $00 : asl : !add $00 : tax
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lda SouthEdgeInfo, x : sta $0a : inx ; needed now, and for nrml transition
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lda SouthEdgeInfo, x : sta $0b : inx ; probably not needed - unsure
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lda SouthEdgeInfo, x : sta $0c ; needed for maths
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rts
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LoadSouthData:
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lda SouthEdgeInfo, x : sta $06
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lda SouthOpenEdge, x : sta $03 : inx
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lda SouthEdgeInfo, x : sta $07
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lda SouthOpenEdge, x : sta $04 : inx
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lda SouthEdgeInfo, x : sta $08
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lda SouthOpenEdge, x : sta $05
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lda $04 : and #$0f : sta $00 : asl : !add $00 : tax
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lda NorthEdgeInfo, x : sta $0a : inx
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lda NorthEdgeInfo, x : sta $0b : inx
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lda NorthEdgeInfo, x : sta $0c
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rts
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LoadWestData:
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lda WestEdgeInfo, x : sta $06
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lda WestOpenEdge, x : sta $03 : inx
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lda WestEdgeInfo, x : sta $07
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lda WestOpenEdge, x : sta $04 : inx
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lda WestEdgeInfo, x : sta $08
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lda WestOpenEdge, x : sta $05
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lda $04 : and #$0f : sta $00 : asl : !add $00 : tax
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lda EastEdgeInfo, x : sta $0a : inx
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lda EastEdgeInfo, x : sta $0b : inx
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lda EastEdgeInfo, x : sta $0c
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rts
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LoadEastData:
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lda EastEdgeInfo, x : sta $06
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lda EastOpenEdge, x : sta $03 : inx
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lda EastEdgeInfo, x : sta $07
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lda EastOpenEdge, x : sta $04 : inx
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lda EastEdgeInfo, x : sta $08
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lda EastOpenEdge, x : sta $05
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lda $04 : and #$0f : sta $00 : asl : !add $00 : tax
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lda WestEdgeInfo, x : sta $0a : inx
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lda WestEdgeInfo, x : sta $0b : inx
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lda WestEdgeInfo, x : sta $0c
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rts
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DetectNorthEdge:
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ldx #$ff
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lda $a2
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cmp #$82 : bne +
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lda $22 : cmp #$50 : bcs ++
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ldx #$01 : bra .end
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++ ldx #$00 : bra .end
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+ cmp #$83 : bne +
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ldx #$02 : bra .end
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+ cmp #$84 : bne +
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lda $a9 : beq ++
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lda $22 : cmp #$78 : bcs +++
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ldx #$04 : bra .end
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+++ ldx #$05 : bra .end
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++ lda $22 : cmp #$78 : bcs ++
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ldx #$03 : bra .end
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++ ldx #$04 : bra .end
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+ cmp #$85 : bne +
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ldx #$06 : bra .end
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+ cmp #$db : bne +
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lda $a9 : beq ++
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lda $22 : beq ++
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ldx #$08 : bra .end
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++ ldx #$07 : bra .end
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+ cmp #$dc : bne .end
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lda $a9 : bne ++
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lda $22 : cmp #$b0 : bcs ++
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ldx #$09 : bra .end
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++ ldx #$0a
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.end txa : rts
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DetectSouthEdge:
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ldx #$ff
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lda $a2
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cmp #$72 : bne +
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lda $22 : cmp #$50 : bcs ++
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ldx #$01 : bra .end
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++ ldx #$00 : bra .end
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+ cmp #$73 : bne +
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ldx #$02 : bra .end
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+ cmp #$74 : bne +
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lda $a9 : beq ++
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lda $22 : cmp #$78 : bcs +++
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ldx #$04 : bra .end
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+++ ldx #$05 : bra .end
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++ lda $22 : cmp #$78 : bcs ++
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ldx #$03 : bra .end
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++ ldx #$04 : bra .end
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+ cmp #$75 : bne +
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ldx #$06 : bra .end
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+ cmp #$cb : bne +
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lda $a9 : beq ++
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lda $22 : beq ++
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ldx #$08 : bra .end
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++ ldx #$07 : bra .end
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+ cmp #$cc : bne .end
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lda $a9 : bne ++
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lda $22 : cmp #$b0 : bcs ++
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ldx #$09 : bra .end
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++ ldx #$0a
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.end txa : rts
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DetectWestEdge:
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ldx #$ff
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lda $a2
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cmp #$65 : bne +
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ldx #$00 : bra .end
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+ cmp #$74 : bne +
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ldx #$01 : bra .end
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+ cmp #$75 : bne +
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ldx #$02 : bra .end
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+ cmp #$82 : bne +
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lda $aa : beq ++
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ldx #$03 : bra .end
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++ ldx #$04 : bra .end
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+ cmp #$85 : bne +
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ldx #$05 : bra .end
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+ cmp #$cc : bne +
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lda $aa : beq ++
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ldx #$07 : bra .end
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++ ldx #$06 : bra .end
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+ cmp #$dc : bne .end
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ldx #$08
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.end txa : rts
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DetectEastEdge:
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ldx #$ff
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lda $a2
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cmp #$64 : bne +
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ldx #$00 : bra .end
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+ cmp #$73 : bne +
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ldx #$01 : bra .end
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+ cmp #$74 : bne +
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ldx #$02 : bra .end
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+ cmp #$81 : bne +
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lda $aa : beq ++
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ldx #$04 : bra .end
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++ ldx #$03 : bra .end
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+ cmp #$84 : bne +
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ldx #$05 : bra .end
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+ cmp #$cb : bne +
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lda $aa : beq ++
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ldx #$07 : bra .end
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++ ldx #$06 : bra .end
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+ cmp #$db : bne .end
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ldx #$08
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.end txa : rts
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