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         .import         __STACKSIZE__                   ; Linker generated
  13
  14         .include "zeropage.inc"
  15         .include "supervision.inc"
  16
  17         .export _sv_irq_timer_counter, _sv_irq_dma_counter
  18         .export _sv_nmi_counter
  19
  20 .bss
  21
  22 _sv_irq_dma_counter:    .byte 0
  23 _sv_irq_timer_counter:  .byte 0
  24 _sv_nmi_counter:        .byte 0
  25
  26 .code
  27
  28 reset:
  29         jsr     zerobss
  30
  31         ; initialize data
  32         jsr     copydata
  33
  34         lda     #>(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
  35         sta     sp+1            ; Set argument stack ptr
  36         stz     sp              ; #<(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
  37         jsr     initlib
  38         jsr     _main
  39 _exit:  jsr     donelib
  40 exit:   jmp     exit
  41
  42
  43 .proc   irq
  44         pha
  45         lda     sv_irq_source
  46         and     #SV_IRQ_REQUEST_TIMER
  47         beq     not_timer
  48         lda     sv_timer_quit
  49         inc     _sv_irq_timer_counter
  50 not_timer:
  51         lda     sv_irq_source
  52         and     #SV_IRQ_REQUEST_DMA
  53         beq     not_dma
  54         lda     sv_dma_quit
  55         inc     _sv_irq_dma_counter
  56 not_dma:
  57         pla
  58         rti
  59 .endproc
  60
  61 .proc   nmi
  62         inc     _sv_nmi_counter
  63         rti
  64 .endproc
  65
  66 ; removing this segment gives only a warning
  67         .segment "FFF0"
  68 .proc reset32kcode
  69         lda     #(6<<5)
  70         sta     sv_bank
  71 ; now the 32kbyte image can reside in the top of 64kbyte, 128kbyte roms
  72         jmp     reset
  73 .endproc
  74
  75         .segment "VECTOR"
  76
  77 .word   nmi
  78 .word   reset32kcode
  79 .word   irq
  80
  81