Added an interrupt facility similar to that on the C128 and Plus/4

git-svn-id: svn://svn.cc65.org/cc65/trunk@2956 b7a2c559-68d2-44c3-8de9-860c34a00d81

diff --git a/libsrc/c64/crt0.s b/libsrc/c64/crt0.s
index f75a5c46b1e11bb8337b9d6b01ae964c762a0f95..20f0827f6f662d92ae02243540c3344b18c56122 100644 (file)
--- a/libsrc/c64/crt0.s
+++ b/libsrc/c64/crt0.s
@@ -5,10 +5,11 @@
 ;
 
        .export         _exit
-       .import         initlib, donelib
+       .import         initlib, donelib, condes
                .import         zerobss, push0
        .import         callmain
         .import         RESTOR, BSOUT, CLRCH
+       .import         __IRQFUNC_TABLE__, __IRQFUNC_COUNT__
        .import         __RAM_START__, __RAM_SIZE__     ; Linker generated
 
         .include        "zeropage.inc"
@@ -76,21 +77,48 @@ 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
-       jsr     donelib         ; Run module destructors
+NoIRQ2: jsr    donelib
 
 ; Copy back the zero page stuff
 
                ldx     #zpspace-1
-L2:    lda     zpsave,x
-       sta     sp,x
-       dex
+L2:    lda     zpsave,x
+       sta     sp,x
+       dex
                bpl     L2
 
 ; Place the program return code into ST
@@ -109,6 +137,16 @@ 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
+       ldy     #<(__IRQFUNC_COUNT__*2)
+               lda     #<__IRQFUNC_TABLE__
+       ldx     #>__IRQFUNC_TABLE__
+       jsr     condes                  ; Call the functions
+               jmp     IRQInd                  ; Jump to the saved IRQ vector
 
 ; ------------------------------------------------------------------------
 ; Data
@@ -116,6 +154,7 @@ L2: lda     zpsave,x
 .data
 
 zpsave:        .res    zpspace
+IRQInd: jmp     $0000
 
 .bss
 

diff --git a/src/ld65/cfg/c64.cfg b/src/ld65/cfg/c64.cfg
index 6c5ff8da8fd5ffcdc1449c7e7c28ff18112c2891..417f84e14260a1671b3142955840df4ec192f48c 100644 (file)
--- a/src/ld65/cfg/c64.cfg
+++ b/src/ld65/cfg/c64.cfg
@@ -20,6 +20,11 @@ FEATURES {
            type = destructor,
            label = __DESTRUCTOR_TABLE__,
            count = __DESTRUCTOR_COUNT__;
+    # condes functions with type 2 are called in the interrupt
+    CONDES: segment = RODATA,
+           type = 2,
+           label = __IRQFUNC_TABLE__,
+           count = __IRQFUNC_COUNT__;
 }
 SYMBOLS {
     __STACKSIZE__ = $800;      # 2K stack