Adjusted IRQ handler for new callirq semantics

git-svn-id: svn://svn.cc65.org/cc65/trunk@3498 b7a2c559-68d2-44c3-8de9-860c34a00d81

libsrc/cbm610/cbm610-stdser.s

@@ -353,7 +353,7 @@ IRQ:    lda     #$0F
         ldy     #ACIA::STATUS
         lda     (acia),y        ; Check ACIA status for receive interrupt
      	and 	#$08
-       	beq    	@L9   		; Jump if no ACIA interrupt
+       	beq    	@L10            ; Jump if no ACIA interrupt
         ldy     #ACIA::DATA
         lda    	(acia),y        ; Get byte from ACIA
     	ldx 	RecvFreeCnt  	; Check if we have free space left
@@ -371,6 +371,7 @@ IRQ:    lda     #$0F
         ldy     #ACIA::CMD
         sta     (acia),y
     	sta 	Stopped
+        sec                     ; Interrupt handled
 
 ; Done, switch back to the execution segment
 
@@ -378,6 +379,13 @@ IRQ:    lda     #$0F
         sta     IndReg
         rts
 
+; No ACIA interrupt
+
+@L10:   clc                     ; Interrupt not handled
+        lda     ExecReg
+        sta     IndReg
+        rts
+
 ;----------------------------------------------------------------------------
 ; Try to send a byte. Internal routine. A = TryHard