Add interrupt handling code from Stefan Haubenthal

git-svn-id: svn://svn.cc65.org/cc65/trunk@3264 b7a2c559-68d2-44c3-8de9-860c34a00d81

diff --git a/libsrc/vic20/crt0.s b/libsrc/vic20/crt0.s
index a0425cee7c11e614ce3830196a1270c883f28e57..81a9c025d5844e2b0e44a55a5f58a9df05c76aeb 100644 (file)
--- a/libsrc/vic20/crt0.s
+++ b/libsrc/vic20/crt0.s
@@ -5,15 +5,15 @@
 ;
 
        .export         _exit
-       .import         initlib, donelib
+       .import         initlib, donelib, callirq
                .import         zerobss, push0
        .import         callmain
         .import         RESTOR, BSOUT, CLRCH
+       .import         __IRQFUNC_COUNT__
        .import         __RAM_START__, __RAM_SIZE__     ; Linker generated
 
         .include        "zeropage.inc"
        .include        "vic20.inc"
-       .include        "../cbm/cbm.inc"
 
 ; ------------------------------------------------------------------------
 ; Place the startup code in a special segment.
@@ -70,14 +70,41 @@ L1: lda     sp,x
 
        jsr     initlib
 
+; If we have IRQ functions, chain our stub into the IRQ vector
+
+        lda     #<__IRQFUNC_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
+
 ; Push arguments and call main()
 
-               jsr     callmain
+NoIRQ1: jsr     callmain
+
+; Back from main (This is also the _exit entry). Reset the IRQ vector if we
+; chained it.
+
+_exit:         pha                     ; Save the return code on stack
+       lda     #<__IRQFUNC_COUNT__
+       beq     NoIRQ2
+       lda     IRQInd+1
+       ldx     IRQInd+2
+       sei
+       sta     IRQVec
+       stx     IRQVec+1
+       cli
 
-; Call module destructors. This is also the _exit entry.
+; Run module destructors
 
-_exit:         pha                     ; Save the return code on stack
-       jsr     donelib         ; Run module destructors
+NoIRQ2: jsr    donelib
 
 ; Copy back the zero page stuff
 
@@ -102,12 +129,21 @@ L2:       lda     zpsave,x
        jmp     RESTOR
 
 
+; ------------------------------------------------------------------------
+; 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
 
 zpsave:        .res    zpspace
+IRQInd: jmp     $0000
 
 .bss