cc65/libsrc/supervision/crt0.s

;
; Startup code for cc65 (supervision version)
;

        .export         _exit
        .export         __STARTUP__ : absolute = 1      ; Mark as startup

        .import         _main
        .import         initlib, donelib, copydata
        .import         zerobss
        .import         __RAM_START__, __RAM_SIZE__     ; Linker generated
        .import         __STACKSIZE__                   ; Linker generated

        .include "zeropage.inc"
        .include "supervision.inc"

        .export _sv_irq_timer_counter, _sv_irq_dma_counter
        .export _sv_nmi_counter

.bss

_sv_irq_dma_counter:    .byte 0
_sv_irq_timer_counter:  .byte 0
_sv_nmi_counter:        .byte 0

.code

reset:
        jsr     zerobss

        ; Initialize data.
        jsr     copydata

        lda     #<(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
        ldx     #>(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
        sta     sp
        stx     sp+1            ; Set argument stack ptr
        jsr     initlib
        jsr     _main
_exit:  jsr     donelib
exit:   jmp     exit


.proc   irq
        pha
        lda     sv_irq_source
        and     #SV_IRQ_REQUEST_TIMER
        beq     not_timer
        lda     sv_timer_quit
        inc     _sv_irq_timer_counter
not_timer:
        lda     sv_irq_source
        and     #SV_IRQ_REQUEST_DMA
        beq     not_dma
        lda     sv_dma_quit
        inc     _sv_irq_dma_counter
not_dma:
        pla
        rti
.endproc

.proc   nmi
        inc     _sv_nmi_counter
        rti
.endproc

; Removing this segment gives only a warning.
        .segment "FFF0"
.proc reset32kcode
        lda     #(6<<5) | SV_LCD_ON | SV_NMI_ENABLE_ON
        sta     sv_bank
; Now, the 32Kbyte image can reside in the top of 64Kbyte and 128Kbyte ROMs.
        jmp     reset
.endproc

        .segment "VECTORS"

.word   nmi
.word   reset32kcode
.word   irq