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72 lines
2.0 KiB
ArmAsm
72 lines
2.0 KiB
ArmAsm
.export _zonecounter
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.export __STARTUP__ : absolute = 1
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.export _exit
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.import __ROM_START__
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.import __RAM3_START__, __RAM3_SIZE__
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.import initlib, donelib
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.import zerobss, copydata
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.import IRQStub
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.import push0, _main
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.include "atari7800.inc"
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.include "zeropage.inc"
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INPTCTRL = $01
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.segment "STARTUP"
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start:
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; Startup sequence recommended by Atari.
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; See the 7800 standards document.
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sei ; Initialize 6502
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cld
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lda #$07 ; Lock machine in 7800 mode
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sta INPTCTRL
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lda #$7f ; DMA off
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sta CTRL
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ldx #0 ; OFFSET must always be 0
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stx OFFSET
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stx INPTCTRL ; Make sure joysticks don't freeze
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dex ; Stack pointer = $ff
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txs
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; Set up parameter stack
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lda #<(__RAM3_START__ + __RAM3_SIZE__)
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sta sp
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lda #>(__RAM3_START__ + __RAM3_SIZE__)
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sta sp+1
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jsr copydata
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jsr zerobss
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jsr initlib
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; Call main program (pass empty command line)
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jsr push0 ; argc
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jsr push0 ; argv
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ldy #4 ; Argument size
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jsr _main
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_exit:
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jsr donelib
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jmp start
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NMIHandler:
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inc _zonecounter
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jmp IRQStub
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IRQHandler:
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rti
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.segment "DATA"
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_zonecounter:
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.byte 0
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.segment "ENCRYPTION"
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.res 126, $ff ; Reserved for encryption
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Lfff8: .byte $ff ; Region verification (always $ff)
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Lfff9: .byte $f7 ; Use last 4096 bytes only for encryption
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;;;Lfff9: .byte <(((__ROM_START__/4096)<<4) | 7)
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.segment "VECTORS"
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.word NMIHandler
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.word start
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.word IRQHandler
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