irq.s added

2017-10-16 17:34:32 +02:00 · 2017-10-16 17:34:32 +02:00 · 7b74264720
parent 7107019d6f
commit 7b74264720
1 changed files with 59 additions and 0 deletions
--- a/libsrc/telestrat/irq.s
+++ b/libsrc/telestrat/irq.s
@ -0,0 +1,59 @@
+;
+; IRQ handling (Oric version)
+;
+
+        .export         initirq, doneirq
+        .import         callirq
+
+        .include        "telestrat.inc"
+
+; ------------------------------------------------------------------------
+
+.segment        "ONCE"
+
+initirq:
+        lda     IRQVec
+        ldx     IRQVec+1
+        sta     IRQInd+1
+        stx     IRQInd+2
+        lda     #<IRQStub
+        ldx     #>IRQStub
+        jmp     setvec
+
+; ------------------------------------------------------------------------
+
+.code
+
+doneirq:
+        lda     IRQInd+1
+        ldx     IRQInd+2
+setvec: sei
+        sta     IRQVec
+        stx     IRQVec+1
+        cli
+        rts
+
+; ------------------------------------------------------------------------
+
+.segment        "LOWCODE"
+
+IRQStub:
+        cld                             ; Just to be sure
+        pha
+        txa
+        pha
+        tya
+        pha
+        jsr     callirq                 ; Call the functions
+        pla
+        tay
+        pla
+        tax
+        pla
+        jmp     IRQInd                  ; Jump to the saved IRQ vector
+
+; ------------------------------------------------------------------------
+
+.data
+
+IRQInd: jmp     $0000