Added support for chained interrupt handlers installed with .condes type 2.

git-svn-id: svn://svn.cc65.org/cc65/trunk@3953 b7a2c559-68d2-44c3-8de9-860c34a00d81

diff --git a/libsrc/c16/crt0.s b/libsrc/c16/crt0.s
index 1541d7675e23f561ed45a88e191a295f5c3e2303..3e48dbe4b7315e0b509280058483c9a0e89aa73f 100644 (file)
--- a/libsrc/c16/crt0.s
+++ b/libsrc/c16/crt0.s
@@ -8,9 +8,10 @@
 ;
 
        .export         _exit
-       .import         initlib, donelib
-       .import         push0, callmain, zerobss
+       .import         initlib, donelib, callirq
+       .import         callmain, zerobss
         .import         MEMTOP, RESTOR, BSOUT, CLRCH
+       .import         __INTERRUPTOR_COUNT__
 
         .include        "zeropage.inc"
        .include        "../plus4/plus4.inc"
@@ -66,9 +67,24 @@ L1:  lda     sp,x
 MemOk: stx     sp
        sty     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()
 
@@ -79,9 +95,21 @@ MemOk:       stx     sp
 _exit:         pha                     ; Save the return code on stack
        jsr     donelib         ; Run module destructors
 
+; Reset the IRQ vector if we chained it.
+
+        pha                    ; Save the return code on stack
+       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
@@ -101,6 +129,20 @@ 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
+
+IRQInd: jmp     $0000
 
 .segment        "ZPSAVE"