Diffstat (limited to 'zpu/hdl/zpu4/test/interrupt/int.c')
1 files changed, 40 insertions, 0 deletions
diff --git a/zpu/hdl/zpu4/test/interrupt/int.c b/zpu/hdl/zpu4/test/interrupt/int.c
new file mode 100644
@@ -0,0 +1,40 @@
+ * Shows usage of interrupts. Goes along with zpu_core_small_wip.vhd.
+volatile int counter;
+/* Example of single, fixed interval non-maskable, nested interrupt. The interrupt signal is
+ * held high for enough cycles to guarantee that it will be noticed, i.e. longer than
+ * any io access + 4 cycles roughly.
+ * Any non-trivial interrupt controller would have support for
+ * acknowledging interrupts(i.e. keep interrupts asserted until
+ * software acknowledges them via memory mapped IO).
+ /* interrupts are enabled so we need to finish up quickly,
+ * lest we will get infinite recursion!*/
+int main(int argc, char **argv)
+ int t;
+ for (;;)
+ if (t==counter)
+ puts("No interrupt\n");
+ } else
+ puts("Got interrupt\n");