Prevent clock device from locking out all other devices

When the clock device was first in order to be responded to, a fast
enough recurring timer could successfully prevent any other device
from being able to wake the emulator, if a timer was able to expire
in the time it took to run the clock wake handler.

1 files changed, 6 insertions, 1 deletions

diff --git a/src/devices.rs b/src/devices.rs
index 4ba29a8..e0c4280 100644
--- a/src/devices.rs
+++ b/src/devices.rs
@@ -58,10 +58,15 @@ impl StandardDevices {
             };
         }
         self.clock.update_timers();
-        test_wake!(self.clock.wake_flag,  0x3, 0x1000);
+        // The order here is important. If clock comes first, it could
+        // block out all other events with a fast enough recurring timer.
+        // It might be preferable to implement a queue system, so that
+        // the flags are tested in the opposite order to how recently
+        // they were matched.
         test_wake!(self.input.wake_flag,  0x4, 0x0800);
         test_wake!(self.screen.wake_flag, 0x5, 0x0400);
         test_wake!(self.stream.wake_flag, 0x8, 0x0080);
+        test_wake!(self.clock.wake_flag,  0x3, 0x1000);
         return false;
     }
 }