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cc65/libsrc/kim1/crt0.s
2022-09-19 19:56:57 +02:00

48 lines
1.2 KiB
ArmAsm

;
; Startup code for cc65 (KIM-1 version)
;
.export _init, _exit
.export __STARTUP__ : absolute = 1 ; Mark as startup
.import _main
.import initlib, donelib, copydata, zerobss
.import __RAM_START__, __RAM_SIZE__ ; Linker generated
.import __STACKSIZE__ ; Linker generated
.include "zeropage.inc"
.include "kim1.inc"
; Place the startup code in a special segment
.segment "STARTUP"
; A little light housekeeping
_init: cld ; Clear decimal mode
; Set cc65 argument stack pointer
lda #<(__RAM_START__ + __RAM_SIZE__)
sta sp
lda #>(__RAM_START__ + __RAM_SIZE__)
sta sp+1
; Initialize memory storage
jsr zerobss ; Clear BSS segment
jsr copydata ; Initialize DATA segment
jsr initlib ; Run constructors
; Call main()
jsr _main
; Back from main (this is also the _exit entry). There may be a more elegant way to
; return to the monitor on the KIM-1, but I don't know it!
_exit: brk