mirror of https://github.com/stella-emu/stella.git
103 lines
950 B
NASM
103 lines
950 B
NASM
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;;A bankswitching demo for the 0840 EconoBanking technique. 2 4K banks (8K)
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;;By: Rick Skrbina 3/29/09
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processor 6502
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include "vcs.h"
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include "macro.h"
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seg.u vars
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org $80
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BG_Color ds 1
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seg Bank0
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org $E000
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rorg $F000
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Start0
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nop
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nop
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nop
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CLEAN_START
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Start_Frame
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lda #2
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sta VBLANK
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sta VSYNC
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sta WSYNC
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sta WSYNC
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sta WSYNC
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lsr
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sta VSYNC
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ldy #37
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VerticalBlank
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sta WSYNC
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dey
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bne VerticalBlank
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sta VBLANK
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ldy #192
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Picture
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sta WSYNC
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dey
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bne Picture
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lda #2
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sta VBLANK
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ldy #30
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OverScan
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sta WSYNC
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dey
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bne OverScan
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jsr SwchTo1
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lda BG_Color
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sta COLUBK
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jmp Start_Frame
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org $EFE0
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rorg $FFE0
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SwchTo1
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lda $0FFF
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nop
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nop
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nop
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nop
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nop
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nop
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rts
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org $EFFC
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rorg $FFFC
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.word Start0
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.byte "B0"
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seg Bank1
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org $F000
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rorg $F000
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Start1
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lda $0800
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Bank1Sub
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inc BG_Color
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rts
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org $FFE0
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rorg $FFE0
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nop
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nop
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nop
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jsr Bank1Sub
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lda $0800
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org $FFFC
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rorg $FFFC
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.word Start1
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.byte "B1"
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