build: add nvboard support to led light

npc/csrc_nvboard/main.cpp

@@ -0,0 +1,23 @@
+#include <cstdlib>
+#include <cassert>
+#include <cstdlib>
+#include <verilated.h>
+#include <verilated_vcd_c.h>
+#include <Vexample.h>
+#include <nvboard.h>
+
+const int MAX_SIM_TIME=100;
+
+void nvboard_bind_all_pins(Vexample* top);
+
+int main(int argc, char **argv, char **env) {
+    Vexample *top = new Vexample;
+
+    nvboard_bind_all_pins(top);
+    nvboard_init();
+    while (true) {
+        nvboard_update();
+        top->eval();
+    }
+    delete top;
+}