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104 lines
2.2 KiB
ArmAsm
104 lines
2.2 KiB
ArmAsm
;
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; Start-up code for cc65 (CX16 r39 version)
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;
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.export _exit
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.export __STARTUP__ : absolute = 1 ; Mark as start-up
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.import initlib, donelib
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.import zerobss, callmain
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.import CHROUT
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.import __MAIN_START__, __MAIN_SIZE__ ; Linker-generated
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.include "zeropage.inc"
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.include "cx16.inc"
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; ------------------------------------------------------------------------
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; Start-up code
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.segment "STARTUP"
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Start: tsx
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stx spsave ; Save the system stack ptr.
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; Save space by putting some of the start-up code in the ONCE segment
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; which will be re-used by the BSS segment, the heap, and the C stack.
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jsr init
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; Clear the BSS data.
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jsr zerobss
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; Push the command-line arguments, and call main().
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jsr callmain
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; Back from main() [this is also the exit() entry].
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_exit:
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; Put the program return code into BASIC's status variable.
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sta STATUS
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; Run the module destructors.
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jsr donelib
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; Restore the system stuff.
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ldx spsave
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txs ; Restore stack pointer
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ldx ramsave
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stx RAM_BANK ; Restore former RAM bank
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lda #$04
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sta ROM_BANK ; Change back to BASIC ROM
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; Back to BASIC.
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rts
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; ------------------------------------------------------------------------
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.segment "ONCE"
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init:
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; Change from BASIC's ROM to Kernal's ROM.
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stz ROM_BANK
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; Change to the second RAM bank.
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lda RAM_BANK
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sta ramsave ; Save the current RAM bank number
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lda #$01
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sta RAM_BANK
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; Set up the stack.
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lda #<(__MAIN_START__ + __MAIN_SIZE__)
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ldx #>(__MAIN_START__ + __MAIN_SIZE__)
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sta sp
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stx sp+1 ; Set argument stack ptr
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; Switch to the lower/UPPER PetSCII charset.
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lda #$0E
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jsr CHROUT
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; Call the module constructors.
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jmp initlib
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; ------------------------------------------------------------------------
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; Data
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.segment "INIT"
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ramsave:
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.res 1
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spsave: .res 1
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