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--- hardware:interrupts [2016/06/11 21:50]
ex_writer [Screen Interrupts]
+++ hardware:interrupts [2016/06/11 21:56]
ex_writer [Automatic Interrupts (ACTINT)]
@@ Line 115: / Line 115: @@
 <WRAP todo>To be written...</WRAP>
+The Bally Arcade system ROM provides an "automatic" interrupt service via the [[system routines:interrupt scheduler#ACTINT]] system routine.
+In the system ROM source, ACTINT is listed as follows:
+<code z80>
+        DI                      ; MAKE SURE INTERRUPT IS DISABLED
+        PUSH    AF
+        PUSH    BC
+        PUSH    DE
+        PUSH    HL
+        IM      2
+        LD      A,ITAB SHR 8
+        LD      I,A
+        LD      A,$C8
+        OUT     (INLIN),A
+        LD      A,ITAB & 0FFH
+        OUT     (INFBK),A
+        CALL    TIMEZ           ; UPDATE TIMEOUT,MUSIC AND SECONDS
+        LD      C,$0F           ; USE CT0-3
+        CALL    TIMEY           ; DEC CT0-3
+        POP     HL
+        POP     DE
+        POP     BC
+        POP     AF
+        EI
+        RET
+</code>
 ===== Screen Interrupt Examples =====