Oliver added a comment to the Apple2 linker config.

[cc65] / libsrc / pet / crt0.s

diff --git a/libsrc/pet/crt0.s b/libsrc/pet/crt0.s
index a30231268a766ad7c7eab4876d21e2a7c5d2c1bc..23ff90ea353d4ca1bcfe34d602e0cff6f0588b82 100644 (file)
--- a/libsrc/pet/crt0.s
+++ b/libsrc/pet/crt0.s
@@ -1,14 +1,14 @@
 ;
 ; Startup code for cc65 (PET version)
-;
-; This must be the *first* file on the linker command line
 ;
 
        .export         _exit
-       .import         initlib, donelib
+        .export         __STARTUP__ : absolute = 1      ; Mark as startup
+       .import         initlib, donelib, callirq
                .import         zerobss, push0
        .import         callmain
         .import         CLRCH, BSOUT
+       .import         __INTERRUPTOR_COUNT__
 
         .include        "zeropage.inc"
        .include        "pet.inc"
@@ -41,11 +41,19 @@ L1: lda     sp,x
 
        jsr     CLRCH
 
-; Switch to second charset
+; Switch to 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 this
+; information, we need to save and restore it here.
+; Thanks to Stefan Haubenthal for this information!
 
+        lda     FNLEN
+        pha                     ; Save FNLEN
        lda     #14
 ;      sta     $E84C           ; See PET FAQ
        jsr     BSOUT
+        pla
+        sta     FNLEN           ; Restore FNLEN
 
 ; Clear the BSS data
 
@@ -61,27 +69,48 @@ L1: lda     sp,x
        lda     MEMSIZE+1
                sta     sp+1            ; Set argument stack ptr
 
+; If we have IRQ functions, chain our stub into the IRQ vector
+
+       lda     #<__INTERRUPTOR_COUNT__
+       beq     NoIRQ1
+       lda     IRQVec
+       ldx     IRQVec+1
+       sta     IRQInd+1
+       stx     IRQInd+2
+       lda     #<IRQStub
+       ldx     #>IRQStub
+       sei
+       sta     IRQVec
+       stx     IRQVec+1
+       cli
+
 ; Call module constructors
 
-       jsr     initlib
+NoIRQ1: jsr     initlib
 
 ; Push arguments and call main()
 
-       jsr     callmain
+        jsr    callmain
 
 ; Call module destructors. This is also the _exit entry.
 
-_exit:         pha                     ; Save the return code on stack
-       jsr     donelib         ; Run module destructors
+_exit:  pha                    ; Save the return code on stack
+        jsr    donelib
 
-; Restore system stuff
+; Reset the IRQ vector if we chained it.
 
-       ldx     spsave
-       txs                     ; Restore stack pointer
+       lda     #<__INTERRUPTOR_COUNT__
+       beq     NoIRQ2
+       lda     IRQInd+1
+       ldx     IRQInd+2
+       sei
+       sta     IRQVec
+       stx     IRQVec+1
+       cli
 
 ; Copy back the zero page stuff
 
-       ldx     #zpspace-1
+NoIRQ2: ldx     #zpspace-1
 L2:    lda     zpsave,x
        sta     sp,x
        dex
@@ -92,16 +121,32 @@ L2:        lda     zpsave,x
        pla
        sta     ST
 
+; Restore the stack pointer
+
+       ldx     spsave
+       txs                     ; Restore stack pointer
+
 ; Back to basic
 
                rts
 
+; ------------------------------------------------------------------------
+; The IRQ vector jumps here, if condes routines are defined with type 2.
+
+IRQStub:
+       cld                             ; Just to be sure
+       jsr     callirq                 ; Call the functions
+       jmp     IRQInd                  ; Jump to the saved IRQ vector
 
 ; ------------------------------------------------------------------------
 ; Data
 
 .data
 
+IRQInd: jmp    $0000
+
+.segment        "ZPSAVE"
+
 zpsave:        .res    zpspace
 
 .bss