pbio/drv/clock_test: Fix counting clock.

It did not advance, and even if it did it would use its own counter in different places.

Author: laurensvalk

bricks/simhub/mpconfigport.h

@@ -65,11 +65,8 @@
 // every couple of MicroPython byte codes. This also polls to the event loop.
 #define PYBRICKS_VM_HOOK_LOOP_EXTRA \
     do { \
-        static uint32_t count; \
-        if ((count % 16) == 0) { \
-            extern void pbio_test_clock_tick(uint32_t ticks); \
-            pbio_test_clock_tick(1); \
-        } \
+        extern void pbio_clock_test_advance_eventually(void); \
+        pbio_clock_test_advance_eventually(); \
     } while (0);
 #else
 // When using the wall clock, time advances automatically but we still need to

lib/pbio/drv/clock/clock_test.c

@@ -26,6 +26,23 @@ void pbio_test_clock_tick(uint32_t ticks) {
     pbio_os_request_poll();
 }
 
+/**
+ * Simulates incrementing the clock after a certain number of CPU cycles.
+ *
+ * This should be called from loops that take a very small but nonzero amount
+ * of time.
+ */
+void pbio_clock_test_advance_eventually(void) {
+
+    static uint32_t count = 0;
+
+    if (++count % 16) {
+        return;
+    }
+
+    pbio_test_clock_tick(1);
+}
+
 void pbdrv_clock_init(void) {
 }