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79 lines
2.4 KiB
ArmAsm
79 lines
2.4 KiB
ArmAsm
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.export __STARTUP__ : absolute = 1 ; Mark as startup
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.import initlib, donelib, callmain
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.import push0, _main, zerobss, copydata
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.import IRQStub
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; Linker generated symbols
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.import __RAM_START__, __RAM_SIZE__
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.import __ROM_START__, __ROM_SIZE__
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.import __STARTUP_LOAD__,__STARTUP_RUN__, __STARTUP_SIZE__
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.import __CODE_LOAD__,__CODE_RUN__, __CODE_SIZE__
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.import __RODATA_LOAD__,__RODATA_RUN__, __RODATA_SIZE__
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.include "zeropage.inc"
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.include "gamate.inc"
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.segment "STARTUP"
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.word 0 ; +00 checksum from 7000-7fff (simple 8bit adds)
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.byte 1, 0, 1 ; +02 flags
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.byte "COPYRIGHT BIT CORPORATION", 0, $ff ; +05 copyright
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; system vectors
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jmp reset ; +20 reset entry
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jmp nmi ; +23 nmi entry
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jmp IRQStub ; +26 irq entry (135 hz)
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;-------------------------------------------------------------------------------
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reset:
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; setup the CPU and System-IRQ
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; Initialize CPU
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sei
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cld
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; Setup stack and memory mapping
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ldx #$FF ; Stack top ($01FF)
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txs
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; Clear the BSS data
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jsr zerobss
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; Copy the .data segment to RAM
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jsr copydata
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; setup the stack
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lda #<(__RAM_START__+__RAM_SIZE__)
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sta sp
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lda #>(__RAM_START__+__RAM_SIZE__)
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sta sp + 1
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; Call module constructors
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jsr initlib
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cli ; allow IRQ only after constructors have run
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; Pass an 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 ; call the users code
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; Call module destructors. This is also the _exit entry.
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_exit:
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jsr donelib ; Run module destructors
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; reset (start over)
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jmp reset
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.export initmainargs
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initmainargs:
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rts
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;-------------------------------------------------------------------------------
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nmi:
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rts
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