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98 lines
2.6 KiB
ArmAsm
98 lines
2.6 KiB
ArmAsm
; ---------------------------------------------------------------------------
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; crt0.s
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; ---------------------------------------------------------------------------
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;
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; Startup code for c65el02
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.export _init, _exit
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.import _main
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.export __STARTUP__ : absolute = 1 ; Mark as startup
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.import __STACK_START__, __STACK_SIZE__ ; Linker generated
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.import copydata, zerobss, initlib, donelib
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.include "zeropage.inc"
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.macro MMU command
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.byte $EF
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.byte command
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.endmacro
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.macro XCE
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.byte $FB
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.endmacro
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; ---------------------------------------------------------------------------
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; Place the startup code in a special segment
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.segment "STARTUP"
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;.byte $DB
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; ---------------------------------------------------------------------------
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; A little light 6502 housekeeping
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_init: LDX #$FF ; Initialize stack pointer to $01FF
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TXS
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CLD ; Clear decimal mode
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; ---------------------------------------------------------------------------
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; Set cc65 argument stack pointer
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LDA #<(__STACK_START__ + __STACK_SIZE__ - 1)
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STA sp
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LDA #>(__STACK_START__ + __STACK_SIZE__ - 1)
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STA sp+1
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; ---------------------------------------------------------------------------
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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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; ---------------------------------------------------------------------------
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; Initialize redbus
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; This below is useless right now, probably will be removed
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; from foth boot disk
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;000500 18 CLC
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;000501 FB XCE
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;000502 C2 30 REP #$30
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;000504 A9 00 03 LDA #$0300
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;000507 EF 01 MMU $01
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;000509 EF 02 MMU $02
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;00050B A9 00 04 LDA #$0400
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;00050E EF 03 MMU $03
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;000510 EF 04 MMU $04
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;000512 A9 00 05 LDA #$0500
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;000515 EF 06 MMU $06
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;000517 4C 56 1D JMP $1D56
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;LDA $01 ; Get the main console ID
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;MMU $00
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;LDA #$00 ; Select first line
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;STA $0300
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;LDA #$42 ; Seems to work
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;STA $0310
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;.byte $DB
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; ---------------------------------------------------------------------------
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; Call main()
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JSR _main
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; ---------------------------------------------------------------------------
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; Back from main (this is also the _exit entry): force a software break
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_exit: JSR donelib ; Run destructors
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BRK
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