Merge pull request #130 from greg-king5/caps-lock

[cc65] / libsrc / pet / crt0.s

diff --git a/libsrc/pet/crt0.s b/libsrc/pet/crt0.s
index fb0377677548915ac83359d2838b4f30e70e9d0e..66aed0366f912dcf687849afbbae2116043e4492 100644 (file)
--- a/libsrc/pet/crt0.s
+++ b/libsrc/pet/crt0.s
@@ -1,111 +1,106 @@
 ;
 ; Startup code for cc65 (PET version)
-;
-; This must be the *first* file on the linker command line
 ;
 
-       .export         _exit
-       .import         initlib, donelib
-               .import         zerobss, push0
-       .import         callmain
+        .export         _exit
+        .export         __STARTUP__ : absolute = 1      ; Mark as startup
+        .import         initlib, donelib
+        .import         zerobss, push0
+        .import         callmain
         .import         CLRCH, BSOUT
+        .importzp       ST
 
         .include        "zeropage.inc"
-       .include        "pet.inc"
-       .include        "../cbm/cbm.inc"
+        .include        "pet.inc"
+        .include        "../cbm/cbm.inc"
 
 ; ------------------------------------------------------------------------
-; Place the startup code in a special segment.
-
-.segment               "STARTUP"
+; Startup code
 
-; BASIC header with a SYS call
+.segment        "STARTUP"
 
-        .word   Head            ; Load address
-Head:   .word   @Next
-        .word   .version        ; Line number
-        .byte   $9E,"1037"      ; SYS 1037
-        .byte   $00             ; End of BASIC line
-@Next:  .word   0               ; BASIC end marker
+Start:
 
-; ------------------------------------------------------------------------
-; Actual code
+; Save the zero-page locations that we need.
 
-               ldx     #zpspace-1
-L1:    lda     sp,x
-       sta     zpsave,x        ; Save the zero page locations we need
-       dex
-               bpl     L1
+        ldx     #zpspace-1
+L1:     lda     sp,x
+        sta     zpsave,x
+        dex
+        bpl     L1
 
-; Close open files
+; Switch to the second charset. The routine that is called by BSOUT to switch the
+; character set will use FNLEN as temporary storage -- YUCK! Since the
+; initmainargs routine, which parses the command line for arguments, needs that
+; information, we need to save and restore it here.
+; Thanks to Stefan Haubenthal for this information!
 
-       jsr     CLRCH
+        lda     FNLEN
+        pha                     ; Save FNLEN
+        lda     #14
+;       sta     $E84C           ; See PET FAQ
+        jsr     BSOUT
+        pla
+        sta     FNLEN           ; Restore FNLEN
 
-; Switch to second charset
+; Clear the BSS data.
 
-       lda     #14
-;      sta     $E84C           ; See PET FAQ
-       jsr     BSOUT
+        jsr     zerobss
 
-; Clear the BSS data
+; Save some system stuff; and, set up the stack.
 
-       jsr     zerobss
+        tsx
+        stx     spsave          ; Save the system stack ptr
 
-; Save system stuff and setup the stack
+        lda     MEMSIZE
+        sta     sp
+        lda     MEMSIZE+1
+        sta     sp+1            ; Set argument stack ptr
 
-               tsx
-               stx     spsave          ; Save the system stack ptr
+; Call the module constructors.
 
-       lda     MEMSIZE
-       sta     sp
-       lda     MEMSIZE+1
-               sta     sp+1            ; Set argument stack ptr
+        jsr     initlib
 
-; Call module constructors
+; Push the command-line arguments; and, call main().
 
-       jsr     initlib
+        jsr     callmain
 
-; Push arguments and call main()
+; Call the module destructors. This is also the exit() entry.
 
-       jsr     callmain
+_exit:  pha                     ; Save the return code on stack
+        jsr     donelib
 
-; Call module destructors. This is also the _exit entry.
+; Copy back the zero-page stuff.
 
-_exit:         pha                     ; Save the return code on stack
-       jsr     donelib         ; Run module destructors
+        ldx     #zpspace-1
+L2:     lda     zpsave,x
+        sta     sp,x
+        dex
+        bpl     L2
 
-; Copy back the zero page stuff
+; Store the program return code into BASIC's status variable.
 
-       ldx     #zpspace-1
-L2:    lda     zpsave,x
-       sta     sp,x
-       dex
-               bpl     L2
+        pla
+        sta     ST
 
-; Store the program return code into ST
+; Restore the stack pointer.
 
-       pla
-       sta     ST
+        ldx     spsave
+        txs                     ; Restore stack pointer
 
-; Restore the stack pointer
+; Back to BASIC.
 
-       ldx     spsave
-       txs                     ; Restore stack pointer
+        rts
 
-; Back to basic
+; ------------------------------------------------------------------------
 
-               rts
+.segment        "ZPSAVE"
 
+zpsave: .res    zpspace
 
 ; ------------------------------------------------------------------------
-; Data
-
-.data
-
-zpsave:        .res    zpspace
 
 .bss
 
-spsave:        .res    1
-mmusave:.res   1
-
+spsave: .res    1
+mmusave:.res    1