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         ldx     #>(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
  36         sta     sp
  37         stx     sp+1            ; Set argument stack ptr
  38         jsr     initlib
  39         jsr     _main
  40 _exit:  jsr     donelib
  41 exit:   jmp     exit
  42
  43
  44 .proc   irq
  45         pha
  46         lda     sv_irq_source
  47         and     #SV_IRQ_REQUEST_TIMER
  48         beq     not_timer
  49         lda     sv_timer_quit
  50         inc     _sv_irq_timer_counter
  51 not_timer:
  52         lda     sv_irq_source
  53         and     #SV_IRQ_REQUEST_DMA
  54         beq     not_dma
  55         lda     sv_dma_quit
  56         inc     _sv_irq_dma_counter
  57 not_dma:
  58         pla
  59         rti
  60 .endproc
  61
  62 .proc   nmi
  63         inc     _sv_nmi_counter
  64         rti
  65 .endproc
  66
  67 ; Removing this segment gives only a warning.
  68         .segment "FFF0"
  69 .proc reset32kcode
  70         lda     #(6<<5)
  71         sta     sv_bank
  72 ; Now, the 32Kbyte image can reside in the top of 64Kbyte and 128Kbyte ROMs.
  73         jmp     reset
  74 .endproc
  75
  76         .segment "VECTOR"
  77
  78 .word   nmi
  79 .word   reset32kcode
  80 .word   irq
  81
  82