Added empty IRQ backend.

The driver kernels all require IRQ handling even if the actual drivers don't make use of it. So in order to successfully link a NES program using the joystick and/or TGI driver there has to be at least a "dummy" IRQ backend.

diff --git a/libsrc/nes/irq.s b/libsrc/nes/irq.s
new file mode 100644 (file)
index 0000000..9c026f0
--- /dev/null
+++ b/libsrc/nes/irq.s
@@ -0,0 +1,19 @@
+;
+; IRQ handling (NES version)
+;
+
+        .export         initirq, doneirq
+
+; ------------------------------------------------------------------------
+
+.segment        "INIT"
+
+initirq:
+        rts
+
+; ------------------------------------------------------------------------
+
+.code
+
+doneirq:
+        rts