atari5200: name conio constructor 'initconio'

[cc65] / libsrc / runtime / callirq.s

diff --git a/libsrc/runtime/callirq.s b/libsrc/runtime/callirq.s
index b456ce892c09cd9bf71fd61656a4ce6b878447ef..74a12c4db4f5f58b9e42f5a7534e948bea9cd90a 100644 (file)
--- a/libsrc/runtime/callirq.s
+++ b/libsrc/runtime/callirq.s
@@ -16,20 +16,35 @@
 ;      code avoids this by using locking mechanisms, but it's complex and
 ;      has a size and performance penalty.
 ;
+;   3. Special semantics: An interruptor called by callirq must tell by
+;      setting or resetting the carry flag if the interrupt has been handled
+;      (which means that the interrupt is no longer active at the interrupt
+;      source). callirq will call no other interruptors if this happens. To
+;      simplify code, all interrupt routines will be called with carry clear
+;      on entry.
+;
 ; As the normal condes routine, this one has the limitation of 127 table
 ; entries.
 ;
 
-               .export callirq
-        .export callirq_y       ; Same but with Y preloaded
+        .export         callirq
+        .export         callirq_y       ; Same but with Y preloaded
+        .export         __CALLIRQ__ : absolute = 1
+        .constructor    irq_init, 10
+        .destructor     irq_done, 10
 
-               .import __INTERRUPTOR_TABLE__, __INTERRUPTOR_COUNT__
+        .import         __INTERRUPTOR_TABLE__, __INTERRUPTOR_COUNT__
+        .import         initirq
+        .import         doneirq
 
-.code
+        irq_init :=     initirq
+        irq_done :=     doneirq
 
 ; --------------------------------------------------------------------------
 ; Call all IRQ routines. The function needs to use self modifying code and
-; is thereforce placed in the data segment.
+; is thereforce placed in the data segment. It will return carry set if the
+; interrupt was handled and carry clear if not. The caller may choose to
+; ignore this at will.
 ; NOTE: The routine must not be called if the table is empty!
 
 .data
@@ -37,17 +52,16 @@
 callirq:
         ldy     #.lobyte(__INTERRUPTOR_COUNT__*2)
 callirq_y:
-        dey
+        clc                             ; Preset carry flag
+loop:   dey
         lda     __INTERRUPTOR_TABLE__,y
         sta     jmpvec+2                ; Modify code below
-       dey
+        dey
         lda     __INTERRUPTOR_TABLE__,y
         sta     jmpvec+1                ; Modify code below
-               sty     index+1                 ; Modify code below
-jmpvec: jsr            $FFFF                   ; Patched at runtime
-index:         ldy     #$FF                    ; Patched at runtime
-               bne     callirq_y
-        rts
-
-
-
+        sty     index+1                 ; Modify code below
+jmpvec: jsr     $FFFF                   ; Patched at runtime
+        bcs     done                    ; Bail out if interrupt handled
+index:  ldy     #$FF                    ; Patched at runtime
+        bne     loop
+done:   rts