1370 lines
20 KiB
ArmAsm
1370 lines
20 KiB
ArmAsm
.segment "HEADER"
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INES_MAPPER = 0
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INES_MIRROR = 1
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INES_SRAM = 0
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.byte 'N', 'E', 'S', $1A
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.byte $02
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.byte $01
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.byte INES_MIRROR
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.byte (INES_MAPPER & %11110000)
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.byte $0, $0, $0, $0, $0, $0, $0, $0
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.segment "TILES"
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.incbin "background.chr"
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.incbin "sprite.chr"
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.segment "VECTORS"
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.word nmi
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.word reset
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.word irq
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.segment "CODE"
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reset:
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sei
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lda #0
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sta $2000
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lda #0
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sta $2001
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sta $4015
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sta $4010
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lda #40
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sta $4017
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cld
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ldx #$FF
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txs
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bit $2002
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:
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bit $2002
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bpl :-
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lda #0
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ldx #0
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:
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sta $0000, X
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sta $0100, X
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sta $0200, X
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sta $0300, X
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sta $0400, X
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sta $0500, X
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sta $0600, X
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sta $0700, X
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inx
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bne :-
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lda #255
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ldx #0
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:
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sta oam, X
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inx
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inx
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inx
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inx
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bne :-
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:
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bit $2002
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bpl :-
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lda #%10101000 ; NMI enable, 8x16 sprites, ignored due to 8x16 mode
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sta $2000
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jmp main
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.segment "ZEROPAGE"
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nmi_lock: .res 1
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nmi_count: .res 1
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nmi_ready: .res 1
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nmt_update_len: .res 1
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scroll_x: .res 1
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scroll_y: .res 1
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scroll_nmt: .res 1
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temp: .res 1
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.segment "BSS"
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nmt_update: .res 256
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palette: .res 32
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.segment "OAM"
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oam: .res 256
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.segment "CODE"
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nmi:
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pha
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txa
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pha
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tya
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pha
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lda nmi_lock
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beq :+
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jmp @nmi_end
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:
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lda #1
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sta nmi_lock
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lda nmi_ready
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bne :+
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jmp @ppu_update_end
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:
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cmp #2
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bne :+
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lda #%00000000
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sta $2001
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ldx #0
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stx nmi_ready
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jmp @ppu_update_end
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:
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ldx #0
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stx $2003
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lda #>oam
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sta $4014
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lda #%10101000 ; NMI enable, 8x16 sprites, ignored due to 8x16 mode
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sta $2000
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lda $2002
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lda #$3F
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sta $2006
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stx $2006
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ldx #0
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:
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lda palette, X
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sta $2007
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inx
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cpx #32
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bcc :-
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ldx #0
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cpx nmt_update_len
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bcs @scroll
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@nmt_update_loop:
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lda nmt_update, X
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sta $2006
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inx
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lda nmt_update, X
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sta $2006
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inx
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lda nmt_update, X
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sta $2007
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cpx nmt_update_len
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bcc @nmt_update_loop
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lda #0
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sta nmt_update_len
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@scroll:
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lda scroll_nmt
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and #%00000011
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ora #%10101000
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sta $2000
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lda scroll_x
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sta $2005
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lda scroll_y
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sta $2005
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lda #%00011110
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sta $2001
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ldx #0
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stx nmi_ready
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@ppu_update_end:
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lda #0
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sta nmi_lock
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@nmi_end:
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pla
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tay
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pla
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tax
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pla
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rti
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.segment "CODE"
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irq:
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rti
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.segment "CODE"
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ppu_update:
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lda #1
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sta nmi_ready
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:
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lda nmi_ready
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bne :-
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rts
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ppu_skip:
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lda nmi_count
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:
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cmp nmi_count
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beq :-
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rts
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ppu_off:
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lda #2
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sta nmi_ready
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:
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lda nmi_ready
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bne :-
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rts
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PAD_A = $01
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PAD_B = $02
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PAD_SELECT = $04
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PAD_START = $08
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PAD_U = $10
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PAD_D = $20
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PAD_L = $40
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PAD_R = $80
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.segment "ZEROPAGE"
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gamepad: .res 1
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.segment "CODE"
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; gamepad_poll: this reads the gamepad state into the variable labelled "gamepad"
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; This only reads the first gamepad, and also if DPCM samples are played they can
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; conflict with gamepad reading, which may give incorrect results.
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gamepad_poll:
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; strobe the gamepad to latch current button state
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lda #1
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sta $4016
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lda #0
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sta $4016
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; read 8 bytes from the interface at $4016
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ldx #8
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:
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pha
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lda $4016
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; combine low two bits and store in carry bit
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and #%00000011
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cmp #%00000001
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pla
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; rotate carry into gamepad variable
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ror
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dex
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bne :-
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sta gamepad
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rts
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.segment "RODATA"
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level:
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.byte 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
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.byte 0,1,0,0,1,0,0,0,0,1,0,0,2,7,7,3
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.byte 0,0,0,0,0,0,0,0,0,0,0,0,6,0,0,9
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.byte 0,1,0,0,1,7,7,7,7,1,7,7,6,0,0,9
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.byte 0,0,1,1,0,0,0,0,0,1,0,0,4,8,8,5
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.byte 0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0
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.byte 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
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.byte 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
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.byte 0,0,0,0,1,1,1,1,1,0,0,0,0,0,0,0
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.byte 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
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.byte 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
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.byte 0,0,0,0,0,0,0,0,0,0,0,10,10,10,10,10
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.byte 0,0,1,0,0,0,0,1,0,0,0,11,11,11,11,11
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.byte 0,1,2,3,4,5,6,7,8,9,0,11,11,11,11,11
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.byte 0,0,0,0,0,0,0,0,0,0,0,11,11,11,11,11
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metatiles:
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.byte 0,0,0,0,0
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.byte $14,$15,$16,$17,1 ; Full block
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.byte $14,$18,$1B,$00,0 ; up / left
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.byte $18,$15,$00,$19,0 ; up / right
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.byte $1B,$00,$16,$1A,0 ; down / left
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.byte $00,$19,$1A,$17,0 ; down / right
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.byte $1B,$00,$1B,$00,0 ; left
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.byte $18,$18,$00,$00,0 ; up
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.byte $00,$00,$1A,$1A,0 ; down
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.byte $00,$19,$00,$19,0 ; right
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.byte $10,$11,$12,$13,2
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.byte $12,$12,$12,$12,2
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example_palette:
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.byte $0F,$00,$3D,$20 ; greyscale
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.byte $0F,$3D,$30,$00 ; whitescale
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.byte $0F,$09,$1A,$16 ; grass
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.byte $0F,$15,$26,$37 ; bg0 purple/pink
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.byte $0F,$2D,$10,$3D ; reboot bottom
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.byte $0F,$2D,$10,$2C ; reboot eye
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.byte $0F,$01,$11,$21 ; bg2 blue
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.byte $0F,$00,$10,$30 ; bg3 greyscale
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; .byte $0F,$18,$28,$38 ; sp0 yellow
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; .byte $0F,$14,$24,$34 ; sp1 purple
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; .byte $0F,$1B,$2B,$3B ; sp2 teal
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; .byte $0F,$12,$22,$32 ; sp3 marine
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.segment "ZEROPAGE"
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buttons: .res 1
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player_pos_x: .res 1
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player_pos_y: .res 1
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player_subpos_x: .res 1 ; XXXXYYYY | first 4 bits X subposition, last 4 bits Y
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player_subpos_y: .res 1 ; XXXXYYYY | first 4 bits X subposition, last 4 bits Y
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player_vel_x: .res 1 ; +PPPSSSS | first bit sign, next 3 pixels, last subpixels
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player_vel_y: .res 1 ; in subpixels
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player_status: .res 1 ; 76543210 | 0: facing (0 right, 1 left)
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; | 7: talking
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horizontal_speed: .res 1
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cursor_x: .res 1
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cursor_y: .res 1
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temp_x: .res 1
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temp_y: .res 1
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temp_mul: .res 1
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var_m: .res 1
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var_n: .res 1
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var_o: .res 1
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var_p: .res 1
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jump_pressed_last_frame: .res 1
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frame_counter: .res 1
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last_frame_jumped: .res 1
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last_frame_moving: .res 1
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.segment "CODE"
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main:
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ldx #0
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:
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lda example_palette, X
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sta palette, X
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inx
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cpx #32
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bcc :-
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jsr setup_background
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jsr ppu_update
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lda #$40
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sta cursor_x
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sta cursor_y
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lda #0
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sta frame_counter
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sta last_frame_jumped
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jsr init_objects
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@loop:
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lda $2002
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lda frame_counter
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clc
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adc #1
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sta frame_counter
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sta scroll_x
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jsr controller
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jsr movement
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lda player_pos_x
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@draw:
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jsr draw_player
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jsr ppu_update
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jmp @loop
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draw_player:
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lda player_pos_y
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sec
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sbc #1
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sta oam + (4 * 2) + 0
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sta oam + (4 * 3) + 0
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sec
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sbc #16
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sta oam + (4 * 0) + 0
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sta oam + (4 * 1) + 0
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lda player_status
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and #%00000001
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cmp #0
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bne :+
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lda player_pos_x
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sec
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sbc scroll_x
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sta oam + (4 * 1) + 3
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sta oam + (4 * 3) + 3
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sec
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sbc #8
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sta oam + (4 * 0) + 3
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sta oam + (4 * 2) + 3
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jmp :++
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:
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lda player_pos_x
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sec
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sbc scroll_x
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sta oam + (4 * 0) + 3
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sta oam + (4 * 2) + 3
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sec
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sbc #8
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sta oam + (4 * 1) + 3
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sta oam + (4 * 3) + 3
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:
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lda player_status
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and #%10000000
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cmp #0
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bne :+
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lda #$45
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jmp :++
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:
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lda #$49
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:
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sta oam + (4 * 0) + 1
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clc
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adc #2
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sta oam + (4 * 1) + 1
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lda #$65
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sta oam + (4 * 2) + 1
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lda #$67
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sta oam + (4 * 3) + 1
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lda player_status
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and #%00000001
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cmp #0
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beq :+
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lda #%01000000
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jmp :++
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:
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lda #%00000000
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:
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ora #%00000001
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sta oam + (4 * 0) + 2
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ora #%00000001
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sta oam + (4 * 1) + 2
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and #%11111100
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sta oam + (4 * 2) + 2
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and #%11111100
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sta oam + (4 * 3) + 2
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rts
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init_objects:
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lda #0
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sta var_n
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ldx #0
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:
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lda var_n
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clc
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adc #8
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sta var_n
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sta player_pos_y, X ; Set Y position
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sta player_pos_x, X ; Set X position
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txa
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lsr
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lsr
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sta oam+1, X
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inx
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inx
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inx
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inx
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cpx #(8*4)
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bne :-
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lda #0
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sta player_vel_x
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sta player_vel_y
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sta player_status
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lda #%00101000
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sta horizontal_speed
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rts
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draw:
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@end:
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rts
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movement:
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; Talking
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ldx #0
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jsr btn_b
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cmp #0
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beq :+
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lda player_status
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ora #%10000000
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sta player_status
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jmp :++
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:
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lda player_status
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and #%01111111
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sta player_status
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:
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; Horizontal velocity
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ldx #0
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jsr btn_right
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cmp #0
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beq :+
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ldx #1
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lda horizontal_speed
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sta player_vel_x
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lda player_status
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and #%11111110
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sta player_status
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lda frame_counter
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sta last_frame_moving
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:
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jsr btn_left
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cmp #0
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beq :+
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ldx #1
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lda horizontal_speed
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eor #%11111111
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clc
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adc #1
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sta player_vel_x
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lda player_status
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ora #%00000001
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sta player_status
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lda frame_counter
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sta last_frame_moving
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:
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cpx #1 ; skip decay if right or left pressed
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beq @end
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lda frame_counter
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clc
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sbc last_frame_moving
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and #3
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cmp #0
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bne @end
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lda player_vel_x
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and #%01111111
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cmp #0
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beq @end ; If player_vel_x = 0, skip decay
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lda player_vel_x
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and #%10000000
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; If player_vel_x positive, decrement
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bne :++
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lda player_vel_x
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sec
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sbc #16
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sta player_vel_x
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cmp #0
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bpl :+
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; negative, clamp to 0
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lda #0
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sta player_vel_x
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:
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jmp @end
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|
:
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; Else if player_vel_x < 0, increment
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lda player_vel_x
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clc
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adc #16
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sta player_vel_x
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cmp #0
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beq :+
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bmi :+
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; positive, clamp to 0
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lda #0
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sta player_vel_x
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:
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@end:
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|
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; Jump
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jsr btn_a
|
|
cmp #0
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beq @fail_jump ; If jump not pressed, forget it
|
|
lda jump_pressed_last_frame
|
|
cmp #1
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beq @fail_jump ; If jump last frame, forget it
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|
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; Jump newly pressed this frame
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lda #249
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sta player_vel_y
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lda frame_counter
|
|
sta last_frame_jumped
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|
|
|
@fail_jump:
|
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|
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jsr btn_a
|
|
sta jump_pressed_last_frame
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|
|
|
|
|
; Gravity
|
|
lda frame_counter
|
|
sec
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|
sbc last_frame_jumped
|
|
and #%00000001
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|
cmp #0
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|
bne :+
|
|
lda player_vel_y
|
|
clc
|
|
adc #1 ; Add 2 to velocity
|
|
sta player_vel_y
|
|
:
|
|
|
|
; Apply Y velocity
|
|
lda player_pos_y
|
|
clc
|
|
adc player_vel_y
|
|
sta player_pos_y
|
|
|
|
; Apply X velocity
|
|
; Position
|
|
lda player_vel_x
|
|
and #%10000000
|
|
cmp #0
|
|
bne :+
|
|
; 0: right
|
|
lda player_vel_x
|
|
and #%01111111
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
adc player_pos_x
|
|
sta player_pos_x ; add pixels
|
|
|
|
lda player_vel_x
|
|
; A contains signed subpixels
|
|
|
|
clc
|
|
adc player_subpos_x ; add subposition and velocity subpixels
|
|
and #%00001111
|
|
cmp player_subpos_x ; if A (result) is less than current subpos, overflow occurred
|
|
sta player_subpos_x
|
|
beq @end_add_subpos
|
|
bcs @end_add_subpos ; so skip if subpos is smaller than result
|
|
ldx player_pos_x
|
|
inx
|
|
stx player_pos_x
|
|
@end_add_subpos:
|
|
|
|
jmp :++
|
|
:
|
|
; 1: left
|
|
lda player_vel_x
|
|
sec
|
|
ror
|
|
sec
|
|
ror
|
|
sec
|
|
ror
|
|
sec
|
|
ror
|
|
ora #%10000000
|
|
clc
|
|
adc #1
|
|
clc
|
|
adc player_pos_x
|
|
sta player_pos_x ; add pixels
|
|
|
|
|
|
lda player_vel_x
|
|
; A contains signed subpixels
|
|
|
|
clc
|
|
adc player_subpos_x ; add subposition and velocity subpixels
|
|
and #%00001111
|
|
cmp player_subpos_x ; if A (result) is greater than current subpos, underflow occurred
|
|
sta player_subpos_x
|
|
beq @end_sub_subpos
|
|
bcc @end_sub_subpos ; so skip if subpos is bigger than result
|
|
ldx player_pos_x
|
|
dex
|
|
stx player_pos_x
|
|
@end_sub_subpos:
|
|
:
|
|
|
|
|
|
; load x pos, filter blocks, check up and down
|
|
|
|
lda player_vel_y
|
|
cmp #0
|
|
bmi :+ ; branch if moving up
|
|
jsr downward_collision_check
|
|
jsr left_collision_check
|
|
jsr right_collision_check
|
|
jsr upward_collision_check
|
|
jmp :++
|
|
:
|
|
jsr upward_collision_check
|
|
jsr left_collision_check
|
|
jsr right_collision_check
|
|
jsr downward_collision_check
|
|
:
|
|
|
|
rts
|
|
|
|
; Keep grounded
|
|
cmp #200
|
|
bcc :+
|
|
lda #0
|
|
sta player_vel_y
|
|
lda #200
|
|
sta player_pos_y
|
|
:
|
|
; Bonk
|
|
lda #8
|
|
cmp player_pos_y
|
|
bcc :+
|
|
lda #0
|
|
sta player_vel_y
|
|
lda #8
|
|
sta player_pos_y
|
|
:
|
|
|
|
rts
|
|
|
|
setup_background:
|
|
lda $2002 ; reset latch
|
|
lda #$20
|
|
sta $2006
|
|
lda #$00
|
|
sta $2006
|
|
; empty nametable
|
|
lda #0
|
|
ldy #30 ; 30 rows
|
|
:
|
|
ldx #32 ; 32 columns
|
|
:
|
|
sta $2007
|
|
dex
|
|
bne :-
|
|
dey
|
|
bne :--
|
|
|
|
lda #0
|
|
sta var_o
|
|
@nametable_start:
|
|
lda $2002
|
|
lda #$24
|
|
ldx var_o
|
|
cpx #1
|
|
bne :+
|
|
lda #$24
|
|
:
|
|
sta $2006
|
|
lda #$00
|
|
sta $2006
|
|
ldy #0
|
|
@row_start:
|
|
ldx #0
|
|
:
|
|
txa
|
|
pha
|
|
|
|
; index is (Y * 16) + X
|
|
stx temp_x
|
|
lda #16
|
|
jsr mul_y
|
|
clc
|
|
adc temp_x
|
|
tax
|
|
|
|
lda level, X
|
|
ldx #5
|
|
jsr mul_x
|
|
tax
|
|
|
|
lda metatiles+0, X
|
|
sta $2007
|
|
lda metatiles+1, X
|
|
sta $2007
|
|
|
|
pla
|
|
tax
|
|
inx
|
|
cpx #16
|
|
bne :-
|
|
|
|
; again
|
|
ldx #0
|
|
:
|
|
txa
|
|
pha
|
|
|
|
; index is (Y * 16) + X
|
|
stx temp_x
|
|
lda #16
|
|
jsr mul_y
|
|
clc
|
|
adc temp_x
|
|
tax
|
|
|
|
lda level, X
|
|
ldx #5
|
|
jsr mul_x
|
|
tax
|
|
|
|
lda metatiles+2, X
|
|
sta $2007
|
|
lda metatiles+3, X
|
|
sta $2007
|
|
|
|
pla
|
|
tax
|
|
inx
|
|
cpx #16
|
|
bne :-
|
|
iny
|
|
cpy #15
|
|
bne @row_start
|
|
|
|
|
|
; clear attributes
|
|
;lda #0
|
|
;ldx #64 ; 64 bytes
|
|
;:
|
|
; lda #%11100100
|
|
;
|
|
; sta $2007
|
|
; dex
|
|
; bne :-
|
|
|
|
lda #0
|
|
sta $50
|
|
|
|
ldy #0
|
|
:
|
|
tya
|
|
pha
|
|
|
|
ldx #0
|
|
:
|
|
tya
|
|
pha
|
|
txa
|
|
pha
|
|
|
|
tya
|
|
asl
|
|
asl
|
|
asl
|
|
asl
|
|
asl
|
|
sta temp_y
|
|
|
|
txa
|
|
asl
|
|
|
|
clc
|
|
adc temp_y
|
|
|
|
tax
|
|
|
|
lda level, X
|
|
tay
|
|
lda #5
|
|
jsr mul_y
|
|
tay
|
|
lda metatiles+4, Y
|
|
sta temp_x
|
|
|
|
lda level+1, X
|
|
tay
|
|
lda #5
|
|
jsr mul_y
|
|
tay
|
|
lda metatiles+4, Y
|
|
asl
|
|
asl
|
|
adc temp_x
|
|
sta temp_x
|
|
|
|
lda level+16, X
|
|
tay
|
|
lda #5
|
|
jsr mul_y
|
|
tay
|
|
lda metatiles+4, Y
|
|
asl
|
|
asl
|
|
asl
|
|
asl
|
|
adc temp_x
|
|
sta temp_x
|
|
|
|
lda level+17, X
|
|
tay
|
|
lda #5
|
|
jsr mul_y
|
|
tay
|
|
lda metatiles+4, Y
|
|
asl
|
|
asl
|
|
asl
|
|
asl
|
|
asl
|
|
asl
|
|
adc temp_x
|
|
sta $2007
|
|
|
|
ldx $50
|
|
inx
|
|
stx $50
|
|
|
|
sta $60, X
|
|
|
|
pla
|
|
tax
|
|
pla
|
|
tay
|
|
inx
|
|
cpx #8
|
|
bne :-
|
|
|
|
pla
|
|
tay
|
|
iny
|
|
cpy #8
|
|
bne :--
|
|
|
|
ldx var_o
|
|
cpx #$20
|
|
bne :+
|
|
ldx #$24
|
|
stx var_o
|
|
jmp @nametable_start
|
|
:
|
|
|
|
rts
|
|
|
|
mul_x:
|
|
cmp #0
|
|
beq @zero
|
|
cpx #0
|
|
beq @zero
|
|
|
|
sta temp_mul
|
|
|
|
txa
|
|
pha
|
|
lda #0
|
|
:
|
|
clc
|
|
adc temp_mul
|
|
dex
|
|
bne :-
|
|
sta temp_mul
|
|
pla
|
|
tax
|
|
lda temp_mul
|
|
rts
|
|
|
|
@zero:
|
|
lda #0
|
|
rts
|
|
|
|
mul_y:
|
|
cmp #0
|
|
beq @zero
|
|
cpy #0
|
|
beq @zero
|
|
|
|
sta temp_mul
|
|
|
|
tya
|
|
pha
|
|
lda #0
|
|
:
|
|
clc
|
|
adc temp_mul
|
|
dey
|
|
bne :-
|
|
sta temp_mul
|
|
pla
|
|
tay
|
|
lda temp_mul
|
|
rts
|
|
|
|
@zero:
|
|
lda #0
|
|
rts
|
|
|
|
controller:
|
|
lda #1
|
|
sta $4016
|
|
sta buttons
|
|
lda #0
|
|
sta $4016
|
|
:
|
|
lda $4016
|
|
lsr
|
|
rol buttons
|
|
bcc :-
|
|
|
|
rts
|
|
|
|
btn_right:
|
|
lda buttons
|
|
and #%00000001
|
|
rts
|
|
|
|
btn_left:
|
|
lda buttons
|
|
and #%00000010
|
|
lsr
|
|
rts
|
|
|
|
btn_down:
|
|
lda buttons
|
|
and #%00000100
|
|
lsr
|
|
lsr
|
|
rts
|
|
|
|
btn_up:
|
|
lda buttons
|
|
and #%00001000
|
|
lsr
|
|
lsr
|
|
lsr
|
|
rts
|
|
|
|
btn_start:
|
|
lda buttons
|
|
and #%00010000
|
|
lsr
|
|
lsr
|
|
lsr
|
|
lsr
|
|
rts
|
|
|
|
btn_select:
|
|
lda buttons
|
|
and #%00100000
|
|
lsr
|
|
lsr
|
|
lsr
|
|
lsr
|
|
lsr
|
|
rts
|
|
|
|
btn_b:
|
|
lda buttons
|
|
and #%01000000
|
|
lsr
|
|
lsr
|
|
lsr
|
|
lsr
|
|
lsr
|
|
lsr
|
|
rts
|
|
|
|
btn_a:
|
|
lda buttons
|
|
and #%10000000
|
|
lsr
|
|
lsr
|
|
lsr
|
|
lsr
|
|
lsr
|
|
lsr
|
|
lsr
|
|
rts
|
|
|
|
downward_collision_check:
|
|
lda #0
|
|
sta var_n
|
|
@begin_check:
|
|
lda player_pos_x
|
|
ldx var_n
|
|
cpx #0
|
|
bne :+
|
|
sec
|
|
sbc #5
|
|
jmp :++
|
|
:
|
|
clc
|
|
adc #4
|
|
:
|
|
; divide by 16
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
sta temp_x
|
|
|
|
lda player_pos_y
|
|
; divide by 16
|
|
clc
|
|
adc #8
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
tay
|
|
|
|
lda #16
|
|
jsr mul_y
|
|
adc temp_x
|
|
tax
|
|
lda level, X
|
|
cmp #0
|
|
beq :+
|
|
tya
|
|
asl
|
|
asl
|
|
asl
|
|
asl
|
|
sec
|
|
sbc #8
|
|
cmp player_pos_y
|
|
bcs :+
|
|
sta player_pos_y
|
|
lda #0
|
|
sta player_vel_y
|
|
:
|
|
|
|
ldx var_n
|
|
inx
|
|
stx var_n
|
|
cpx #1
|
|
beq @begin_check
|
|
|
|
rts
|
|
|
|
upward_collision_check:
|
|
lda #0
|
|
sta var_n
|
|
@begin_check:
|
|
lda player_pos_x
|
|
ldx var_n
|
|
cpx #0
|
|
bne :+
|
|
sec
|
|
sbc #5
|
|
jmp :++
|
|
:
|
|
clc
|
|
adc #4
|
|
:
|
|
; divide by 16
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
sta temp_x
|
|
|
|
lda player_pos_y
|
|
; divide by 16
|
|
sec
|
|
sbc #8
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
tay
|
|
|
|
lda #16
|
|
jsr mul_y
|
|
adc temp_x
|
|
tax
|
|
lda level, X
|
|
cmp #0
|
|
beq :+
|
|
iny
|
|
tya
|
|
asl
|
|
asl
|
|
asl
|
|
asl
|
|
clc
|
|
adc #8
|
|
cmp player_pos_y
|
|
bcc :+
|
|
sta player_pos_y
|
|
lda #0
|
|
sta player_vel_y
|
|
:
|
|
|
|
ldx var_n
|
|
inx
|
|
stx var_n
|
|
cpx #1
|
|
beq @begin_check
|
|
|
|
rts
|
|
|
|
right_collision_check:
|
|
lda #0
|
|
sta var_n
|
|
@begin_check:
|
|
lda player_pos_x
|
|
; divide by 16
|
|
clc
|
|
adc #8
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
sta temp_x
|
|
|
|
lda player_pos_y
|
|
ldx var_n
|
|
cpx #0
|
|
bne :+
|
|
sec
|
|
sbc #7
|
|
jmp :++
|
|
:
|
|
clc
|
|
adc #6
|
|
:
|
|
; divide by 16
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
tay
|
|
|
|
lda #16
|
|
jsr mul_y
|
|
adc temp_x
|
|
tax
|
|
lda level, X
|
|
cmp #0
|
|
beq :+
|
|
lda temp_x
|
|
asl
|
|
asl
|
|
asl
|
|
asl
|
|
sec
|
|
sbc #8
|
|
cmp player_pos_x
|
|
bcs :+
|
|
sta player_pos_x
|
|
lda #0
|
|
sta player_vel_x
|
|
:
|
|
|
|
ldx var_n
|
|
inx
|
|
stx var_n
|
|
cpx #1
|
|
beq @begin_check
|
|
|
|
rts
|
|
|
|
left_collision_check:
|
|
lda #0
|
|
sta var_n
|
|
@begin_check:
|
|
lda player_pos_x
|
|
; divide by 16
|
|
sec
|
|
sbc #8
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
sta temp_x
|
|
|
|
lda player_pos_y
|
|
ldx var_n
|
|
cpx #0
|
|
bne :+
|
|
sec
|
|
sbc #7
|
|
jmp :++
|
|
:
|
|
clc
|
|
adc #6
|
|
:
|
|
; divide by 16
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
clc
|
|
ror
|
|
tay
|
|
|
|
lda #16
|
|
jsr mul_y
|
|
adc temp_x
|
|
tax
|
|
lda level, X
|
|
cmp #0
|
|
beq :+
|
|
lda temp_x
|
|
clc
|
|
adc #1
|
|
asl
|
|
asl
|
|
asl
|
|
asl
|
|
clc
|
|
adc #8
|
|
cmp player_pos_x
|
|
bcc :+
|
|
sta player_pos_x
|
|
lda #0
|
|
sta player_vel_x
|
|
:
|
|
|
|
ldx var_n
|
|
inx
|
|
stx var_n
|
|
cpx #1
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|
beq @begin_check
|
|
|
|
rts
|