mirror of
https://github.com/cc65/cc65.git
synced 2024-12-25 17:29:50 +00:00
118 lines
2.5 KiB
ArmAsm
118 lines
2.5 KiB
ArmAsm
;
|
|
; Startup code for cc65 (C64 version)
|
|
;
|
|
|
|
.export _exit
|
|
.export __STARTUP__ : absolute = 1 ; Mark as startup
|
|
|
|
.import initlib, donelib
|
|
.import zerobss, callmain
|
|
.import BSOUT
|
|
.import __MAIN_START__, __MAIN_SIZE__ ; Linker generated
|
|
.import __STACKSIZE__ ; from configure file
|
|
.importzp ST
|
|
|
|
.include "zeropage.inc"
|
|
|
|
|
|
; ------------------------------------------------------------------------
|
|
; Startup code
|
|
|
|
.segment "STARTUP"
|
|
|
|
Start:
|
|
|
|
; Switch off the BASIC ROM.
|
|
|
|
lda $01
|
|
sta mmusave ; Save the memory configuration
|
|
and #$F8
|
|
ora #$06 ; Enable Kernal+I/O, disable BASIC
|
|
sta $01
|
|
|
|
tsx
|
|
stx spsave ; Save the system stack ptr
|
|
|
|
; Save space by putting some of the start-up code in the ONCE segment,
|
|
; which can be re-used by the BSS segment, the heap and the C stack.
|
|
|
|
jsr init
|
|
|
|
; Clear the BSS data.
|
|
|
|
jsr zerobss
|
|
|
|
; Push the command-line arguments; and, call main().
|
|
|
|
jsr callmain
|
|
|
|
; Back from main() [this is also the exit() entry]. Run the module destructors.
|
|
|
|
_exit: pha ; Save the return code on stack
|
|
jsr donelib
|
|
|
|
; Copy back the zero-page stuff.
|
|
|
|
ldx #zpspace-1
|
|
L2: lda zpsave,x
|
|
sta sp,x
|
|
dex
|
|
bpl L2
|
|
|
|
; Place the program return code into BASIC's status variable.
|
|
|
|
pla
|
|
sta ST
|
|
|
|
; Restore the system stuff.
|
|
|
|
ldx spsave
|
|
txs ; Restore stack pointer
|
|
ldx mmusave
|
|
stx $01 ; Restore memory configuration
|
|
|
|
; Back to BASIC.
|
|
|
|
rts
|
|
|
|
|
|
; ------------------------------------------------------------------------
|
|
|
|
.segment "ONCE"
|
|
|
|
init:
|
|
|
|
; Save the zero-page locations that we need.
|
|
|
|
ldx #zpspace-1
|
|
L1: lda sp,x
|
|
sta zpsave,x
|
|
dex
|
|
bpl L1
|
|
|
|
; Set up the stack.
|
|
|
|
lda #<(__MAIN_START__ + __MAIN_SIZE__)
|
|
ldx #>(__MAIN_START__ + __MAIN_SIZE__)
|
|
sta sp
|
|
stx sp+1 ; Set argument stack ptr
|
|
|
|
; Switch to the second charset.
|
|
|
|
lda #14
|
|
jsr BSOUT
|
|
|
|
; Call the module constructors.
|
|
|
|
jmp initlib
|
|
|
|
|
|
; ------------------------------------------------------------------------
|
|
; Data
|
|
|
|
.segment "INIT"
|
|
|
|
mmusave:.res 1
|
|
spsave: .res 1
|
|
zpsave: .res zpspace
|