git.sur5r.net Git - cc65/blob - libsrc/supervision/crt0.s

   1 ;
   2 ; Startup code for cc65 (supervision version)
   3 ;
   4
   5         .export         _exit
   6         .export         __STARTUP__ : absolute = 1      ; Mark as startup
   7
   8         .import         _main
   9         .import         initlib, donelib, copydata
  10         .import         zerobss
  11         .import         __RAM_START__, __RAM_SIZE__     ; Linker generated
  12
  13         .include "zeropage.inc"
  14         .include "supervision.inc"
  15
  16         .export _sv_irq_timer_counter, _sv_irq_dma_counter
  17         .export _sv_nmi_counter
  18
  19 .bss
  20
  21 _sv_irq_dma_counter:    .byte 0
  22 _sv_irq_timer_counter:  .byte 0
  23 _sv_nmi_counter:        .byte 0
  24
  25 .code
  26
  27 reset:
  28         jsr     zerobss
  29
  30         ; initialize data
  31         jsr     copydata
  32
  33         lda     #>(__RAM_START__ + __RAM_SIZE__)
  34         sta     sp+1            ; Set argument stack ptr
  35         stz     sp              ; #<(__RAM_START__ + __RAM_SIZE__)
  36         jsr     initlib
  37         jsr     _main
  38 _exit:  jsr     donelib
  39 exit:   jmp     exit
  40
  41
  42 .proc   irq
  43         pha
  44         lda     sv_irq_source
  45         and     #SV_IRQ_REQUEST_TIMER
  46         beq     not_timer
  47         lda     sv_timer_quit
  48         inc     _sv_irq_timer_counter
  49 not_timer:
  50         lda     sv_irq_source
  51         and     #SV_IRQ_REQUEST_DMA
  52         beq     not_dma
  53         lda     sv_dma_quit
  54         inc     _sv_irq_dma_counter
  55 not_dma:
  56         pla
  57         rti
  58 .endproc
  59
  60 .proc   nmi
  61         inc     _sv_nmi_counter
  62         rti
  63 .endproc
  64
  65 ; removing this segment gives only a warning
  66         .segment "FFF0"
  67 .proc reset32kcode
  68         lda     #(6<<5)
  69         sta     sv_bank
  70 ; now the 32kbyte image can reside in the top of 64kbyte, 128kbyte roms
  71         jmp     reset
  72 .endproc
  73
  74         .segment "VECTOR"
  75
  76 .word   nmi
  77 .word   reset32kcode
  78 .word   irq
  79
  80