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cc65/libsrc/atmos/crt0.s
cuz eb568293d7 Added support for the Oric atmos (with some help by Debrune Jérôme
<jede@oric.org>)


git-svn-id: svn://svn.cc65.org/cc65/trunk@1297 b7a2c559-68d2-44c3-8de9-860c34a00d81
2002-06-03 20:23:15 +00:00

89 lines
1.7 KiB
ArmAsm

;
; Startup code for cc65 (Oric version)
;
; By Debrune Jérôme <jede@oric.org> and Ullrich von Bassewitz <uz@cc65.org>
;
; This must be the *first* file on the linker command line
;
.export _exit
.import initlib, donelib
.import push0, _main, zerobss
.import __RAM_START__, __RAM_SIZE__ ; Linker generated
; ------------------------------------------------------------------------
; Define and export the ZP variables for the Oric runtime
.exportzp sp, sreg, regsave
.exportzp ptr1, ptr2, ptr3, ptr4
.exportzp tmp1, tmp2, tmp3, tmp4
.exportzp regbank, zpspace
.zeropage
zpstart = *
sp: .res 2 ; Stack pointer
sreg: .res 2 ; Secondary register/high 16 bit for longs
regsave: .res 2 ; slot to save/restore (E)AX into
ptr1: .res 2
ptr2: .res 2
ptr3: .res 2
ptr4: .res 2
tmp1: .res 1
tmp2: .res 1
tmp3: .res 1
tmp4: .res 1
regbank: .res 6 ; 6 byte register bank
zpspace = * - zpstart ; Zero page space allocated
.code
; ------------------------------------------------------------------------
; Actual code
; Clear the BSS data
jsr zerobss
; Save system stuff and setup the stack
tsx
stx spsave ; save system stk ptr
lda #<(__RAM_START__ + __RAM_SIZE__)
sta sp
lda #>(__RAM_START__ + __RAM_SIZE__)
sta sp+1 ; Set argument stack ptr
; Call module constructors
jsr initlib
; Pass an empty command line
jsr push0 ; argc
jsr push0 ; argv
ldy #4 ; Argument size
jsr _main ; call the users code
; Call module destructors. This is also the _exit entry.
_exit: jsr donelib ; Run module destructors
; Restore system stuff
ldx spsave
txs
; Back to BASIC
rts
.bss
spsave: .res 1