Added support for building 'extra' object files.

[cc65] / libsrc / vic20 / crt0.s

diff --git a/libsrc/vic20/crt0.s b/libsrc/vic20/crt0.s
index ca3ff2f496bbb28c508aa8ec8e766ce7f5af5695..24b879e238cc7a90a6076fe89ca72aa8161ceb00 100644 (file)
--- a/libsrc/vic20/crt0.s
+++ b/libsrc/vic20/crt0.s
@@ -1,56 +1,34 @@
 ;
 ; Startup code for cc65 (Vic20 version)
-;
-; This must be the *first* file on the linker command line
 ;
 
        .export         _exit
+       .export         __STARTUP__ : absolute = 1      ; Mark as startup
        .import         initlib, donelib
-               .import         zerobss, push0
-       .import         _main
-        .import         RESTOR, BSOUT, CLRCH
-       .import         __RAM_START__, __RAM_SIZE__     ; Linker generated
-
-        .include        "zeropage.inc"
-       .include        "vic20.inc"
-       .include        "../cbm/cbm.inc"
-
-; ------------------------------------------------------------------------
-; Create an empty LOWCODE segment to avoid linker warnings
+       .import         zerobss, push0
+       .import         callmain
+       .import         RESTOR, BSOUT, CLRCH
+       .import         __RAM_START__, __RAM_SIZE__     ; Linker generated
+       .import         __STACKSIZE__                   ; Linker generated
+       .importzp       ST
 
-.segment        "LOWCODE"
+       .include        "zeropage.inc"
+       .include        "vic20.inc"
 
 ; ------------------------------------------------------------------------
-; Place the startup code in a special segment.
+; Startup code
 
-.segment               "STARTUP"
+.segment       "STARTUP"
 
-; BASIC header with a SYS call
+Start:
 
-        .word   Head            ; Load address
-Head:   .word   @Next
-        .word   1000            ; Line number
-        .byte   $9E             ; SYS token
-        .byte   <(((@Start / 1000) .mod 10) + $30)
-        .byte   <(((@Start /  100) .mod 10) + $30)
-        .byte   <(((@Start /   10) .mod 10) + $30)
-        .byte   <(((@Start /    1) .mod 10) + $30)
-        .byte   $00             ; End of BASIC line
-@Next:  .word   0               ; BASIC end marker
-@Start:
+; Save the zero page locations we need
 
-; ------------------------------------------------------------------------
-; Actual code
-
-       ldx     #zpspace-1
+       ldx     #zpspace-1
 L1:    lda     sp,x
-       sta     zpsave,x        ; Save the zero page locations we need
+       sta     zpsave,x
        dex
-               bpl     L1
-
-; Close open files
-
-       jsr     CLRCH
+       bpl     L1
 
 ; Switch to second charset
 
@@ -63,55 +41,57 @@ L1: lda     sp,x
 
 ; Save system stuff and setup the stack
 
-               tsx
-               stx     spsave          ; Save the system stack ptr
+       tsx
+       stx     spsave          ; Save the system stack ptr
 
-       lda     #<(__RAM_START__ + __RAM_SIZE__)
+       lda     #<(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
        sta     sp
-       lda     #>(__RAM_START__ + __RAM_SIZE__)
-               sta     sp+1            ; Set argument stack ptr
+       lda     #>(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
+       sta     sp+1            ; Set argument stack ptr
 
 ; Call module constructors
 
        jsr     initlib
 
-; Pass an empty command line
+; Push arguments and call main()
 
-               jsr     push0           ; argc
-       jsr     push0           ; argv
+       jsr     callmain
 
-       ldy     #4              ; Argument size
-               jsr     _main           ; call the users code
+; Back from main (This is also the _exit entry). Run module destructors
 
-; Call module destructors. This is also the _exit entry.
-
-_exit: jsr     donelib         ; Run module destructors
-
-; Restore system stuff
-
-       ldx     spsave
-       txs                     ; Restore stack pointer
+_exit: pha                     ; Save the return code on stack
+       jsr     donelib
 
 ; Copy back the zero page stuff
 
-               ldx     #zpspace-1
+       ldx     #zpspace-1
 L2:    lda     zpsave,x
        sta     sp,x
        dex
-               bpl     L2
+       bpl     L2
+
+; Place the program return code into ST
 
-; Reset changed vectors, back to basic
+       pla
+       sta     ST
 
-       jmp     RESTOR
+; Restore the stack pointer
 
+       ldx     spsave
+       txs
+
+; Back to basic
+
+       rts
 
 ; ------------------------------------------------------------------------
-; Data
 
-.data
+.segment       "ZPSAVE"
 
 zpsave:        .res    zpspace
 
+; ------------------------------------------------------------------------
+
 .bss
 
 spsave:        .res    1