main, scheduler: Improve latency by coroutine scheduling

Schedules tasks in the main loop using coroutines so that long running
tasks, particularly relating to the UI, can yield execution in order to
call the poll functions at a tighter interval.

main.cpp

@@ -30,6 +30,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "user_io.h"
 #include "input.h"
 #include "fpga_io.h"
+#include "scheduler.h"
 
 const char *version = "$VER:HPS" VDATE;
 
@@ -75,26 +76,8 @@ int main(int argc, char *argv[])
 	FindStorage();
 	user_io_init((argc > 1) ? argv[1] : "");
 
-	while(1)
-	{
-		if(!is_fpga_ready(1))
-		{
-			printf("FPGA is not ready. JTAG uploading?\n");
-			printf("Waiting for FPGA to be ready...\n");
+	scheduler_init();
+	scheduler_run();
 
-			//enable reset in advance
-			fpga_core_reset(1);
-
-			while (!is_fpga_ready(0))
-			{
-				sleep(1);
-			}
-			reboot(0);
-		}
-
-		user_io_poll();
-		input_poll(0);
-		HandleUI();
-	}
 	return 0;
 }