1
0
mirror of https://github.com/cc65/cc65.git synced 2024-12-27 15:29:46 +00:00
cc65/libsrc/supervision/crt0.s
uz 8216bf1d6a Force an import of the special symbol __STARTUP__ in the C compiler when
main() is encountered. Define this symbol in the startup code. This will
automatically force linking of the startup code which can then reside inside
the standard library as any other object file.


git-svn-id: svn://svn.cc65.org/cc65/trunk@3988 b7a2c559-68d2-44c3-8de9-860c34a00d81
2009-07-31 12:05:42 +00:00

81 lines
1.4 KiB
ArmAsm

;
; 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
.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__)
sta sp+1 ; Set argument stack ptr
stz sp ; #<(__RAM_START__ + __RAM_SIZE__)
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)
sta sv_bank
; now the 32kbyte image can reside in the top of 64kbyte, 128kbyte roms
jmp reset
.endproc
.segment "VECTOR"
.word nmi
.word reset32kcode
.word irq