mirror of
https://github.com/cc65/cc65.git
synced 2024-11-02 18:06:48 +00:00
115 lines
2.1 KiB
ArmAsm
115 lines
2.1 KiB
ArmAsm
;
|
|
; Startup code for cc65 (C16 version)
|
|
;
|
|
; This must be the *first* file on the linker command line
|
|
;
|
|
; Note: The C16 is actually the Plus/4 with just 16KB of memory. So many
|
|
; things are similar here, and we even use the plus4.inc include file.
|
|
;
|
|
|
|
.export _exit
|
|
.import initlib, donelib
|
|
.import push0, _main, zerobss
|
|
.import MEMTOP, RESTOR, BSOUT, CLRCH
|
|
|
|
.include "zeropage.inc"
|
|
.include "../plus4/plus4.inc"
|
|
|
|
|
|
; ------------------------------------------------------------------------
|
|
; Create an empty LOWCODE segment to avoid linker warnings
|
|
|
|
.segment "LOWCODE"
|
|
|
|
; ------------------------------------------------------------------------
|
|
; Place the startup code in a special segment.
|
|
|
|
.segment "STARTUP"
|
|
|
|
; BASIC header with a SYS call
|
|
|
|
.word Head ; Load address
|
|
Head: .word @Next
|
|
.word 1000 ; Line number
|
|
.byte $9E,"4109" ; SYS 4109
|
|
.byte $00 ; End of BASIC line
|
|
@Next: .word 0 ; BASIC end marker
|
|
|
|
; ------------------------------------------------------------------------
|
|
; Actual code
|
|
|
|
ldx #zpspace-1
|
|
L1: lda sp,x
|
|
sta zpsave,x ; save the zero page locations we need
|
|
dex
|
|
bpl L1
|
|
|
|
; Close open files
|
|
|
|
jsr CLRCH
|
|
|
|
; Switch to second charset
|
|
|
|
lda #14
|
|
jsr BSOUT
|
|
|
|
; Clear the BSS data
|
|
|
|
jsr zerobss
|
|
|
|
; Save system stuff and setup the stack
|
|
|
|
tsx
|
|
stx spsave ; save system stk ptr
|
|
|
|
sec
|
|
jsr MEMTOP ; Get top memory
|
|
cpy #$80 ; We can only use the low 32K :-(
|
|
bcc MemOk
|
|
ldy #$80
|
|
ldx #$00
|
|
MemOk: stx sp
|
|
sty 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
|
|
|
|
; Copy back the zero page stuff
|
|
|
|
ldx #zpspace-1
|
|
L2: lda zpsave,x
|
|
sta sp,x
|
|
dex
|
|
bpl L2
|
|
|
|
; Reset changed vectors
|
|
|
|
jmp RESTOR
|
|
|
|
|
|
.data
|
|
zpsave: .res zpspace
|
|
|
|
.bss
|
|
spsave: .res 1
|
|
|
|
|