2023-11-17 02:46:16 +00:00
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;
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2023-11-17 19:08:51 +00:00
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; 2023, Rumbledethumps
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;
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; crt0.s
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2023-11-17 02:46:16 +00:00
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.export _init, _exit
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.import _main
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.export __STARTUP__ : absolute = 1
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.import __RAM_START__, __RAM_SIZE__
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.import copydata, zerobss, initlib, donelib
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.include "rp6502.inc"
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.include "zeropage.inc"
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.segment "STARTUP"
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; Essential 6502 startup the CPU doesn't do
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_init:
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ldx #$FF
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txs
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cld
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; Set cc65 argument stack pointer
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lda #<(__RAM_START__ + __RAM_SIZE__)
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sta sp
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lda #>(__RAM_START__ + __RAM_SIZE__)
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sta sp+1
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; Initialize memory storage
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jsr zerobss ; Clear BSS segment
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jsr copydata ; Initialize DATA segment
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jsr initlib ; Run constructors
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; Call main()
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jsr _main
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; Back from main() also the _exit entry
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; Stack the exit value in case destructors call OS
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_exit:
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phx
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pha
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jsr donelib ; Run destructors
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pla
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sta RIA_A
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plx
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stx RIA_X
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lda #$FF ; exit()
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sta RIA_OP
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stp
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