mirror of https://github.com/stella-emu/stella.git
117 lines
1019 B
NASM
117 lines
1019 B
NASM
;;A bankswitching demo for the F8 BS technique. 2 4K banks (8K total)
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;;By: Rick Skrbina
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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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PF_Color ds 1
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seg Bank_0
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org $E000
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rorg $F000
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nop
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nop
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nop
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Start_0
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CLEAN_START
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; jsr Call_1
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lda #$FF
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sta PF1
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StartFrame
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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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lda #0
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sta VSYNC
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ldy #37
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Vert
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sta WSYNC
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dey
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bne Vert
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lda #0
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sta VBLANK
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ldy #192
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Pic
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sta WSYNC
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dey
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bne Pic
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lda #2
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sta VBLANK
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ldy #30
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Over
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sta WSYNC
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dey
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bne Over
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jsr Call_1
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lda PF_Color
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sta COLUPF
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jmp StartFrame
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org $EFE0
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rorg $FFE0
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Call_1
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stx $FFF9
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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 $EFF8
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rorg $FFF8
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.word $FFFF
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.word Start_0
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.word Start_0
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.word Start_0
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seg Bank_1
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org $F000
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rorg $F000
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Init_1
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sta $FFF8
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Bank1_Sub
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; lda #$0F
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; sta COLUPF
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inc PF_Color
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rts
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org $FFE3
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rorg $FFE3
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jsr Bank1_Sub
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stx $FFF8
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org $FFF8
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.word $FFFF
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.word Init_1
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.word Init_1
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.word Init_1
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