bricks/_common/micropython: Use common pb_event_poll_hook.

This lets us keep all MicroPython code in micropython.c and platform specifics in mphal.c.

This lets us do things like #117 in a platform-agnostic way.

This also renames pb_poll to the more descriptive pb_event_poll_hook.

bricks/_common/micropython.c

@@ -32,6 +32,17 @@
 #include "py/stackctrl.h"
 #include "py/stream.h"
 
+// Implementation for MICROPY_EVENT_POLL_HOOK
+void pb_event_poll_hook(void) {
+    while (pbio_do_one_event()) {
+    }
+
+    mp_handle_pending(true);
+
+    // Platform-specific code to run on completing the poll hook.
+    pb_event_poll_hook_leave();
+}
+
 // callback for when stop button is pressed in IDE or on hub
 void pbsys_main_stop_program(void) {
 

bricks/_common/mphalport.h

@@ -9,3 +9,6 @@ void mp_hal_set_interrupt_char(int c);
 #define mp_hal_ticks_cpu() 0
 #define mp_hal_delay_us pbdrv_clock_delay_us
 void pb_stack_get_info(char **sstack, char **estack);
+
+// Platform-specific code to run on completing the poll hook.
+void pb_event_poll_hook_leave(void);

bricks/_common_stm32/mpconfigport.h

@@ -55,8 +55,8 @@ static inline mp_uint_t disable_irq(void) {
 
 #define MICROPY_EVENT_POLL_HOOK \
     do { \
-        extern void pb_poll(void); \
-        pb_poll(); \
+        extern void pb_event_poll_hook(void); \
+        pb_event_poll_hook(); \
     } while (0);
 
 // We need to provide a declaration/definition of alloca()

bricks/_common_stm32/mphalport.c

@@ -24,13 +24,7 @@ void pb_stack_get_info(char **sstack, char **estack) {
     *estack = (char *)&_estack;
 }
 
-// Implementation for MICROPY_EVENT_POLL_HOOK
-void pb_poll(void) {
-    while (pbio_do_one_event()) {
-    }
-
-    mp_handle_pending(true);
-
+void pb_event_poll_hook_leave(void) {
     // There is a possible race condition where an interrupt occurs and sets the
     // Contiki poll_requested flag after all events have been processed. So we
     // have a critical section where we disable interrupts and check see if there

bricks/ev3rt/mpconfigport.h

@@ -101,8 +101,8 @@ static inline mp_uint_t disable_irq(void) {
 
 #define MICROPY_EVENT_POLL_HOOK \
     do { \
-        extern void pb_poll(void); \
-        pb_poll(); \
+        extern void pb_event_poll_hook(void); \
+        pb_event_poll_hook(); \
     } while (0);
 
 // We need to provide a declaration/definition of alloca()

bricks/ev3rt/mphalport.c

@@ -18,13 +18,7 @@
 #include "kernel_cfg.h"
 #include "kernel/task.h"
 
-
-// Implementation for MICROPY_EVENT_POLL_HOOK
-void pb_poll(void) {
-    while (pbio_do_one_event()) {
-    }
-
-    mp_handle_pending(true);
+void pb_event_poll_hook_leave(void) {
 }
 
 // Runs MicroPython with the given program data.

bricks/nxt/mpconfigport.h

@@ -84,10 +84,8 @@ typedef long mp_off_t;
 
 #define MICROPY_EVENT_POLL_HOOK \
     do { \
-        extern void mp_handle_pending(bool); \
-        mp_handle_pending(true); \
-        extern int pbio_do_one_event(void); \
-        while (pbio_do_one_event()) { } \
+        extern void pb_event_poll_hook(void); \
+        pb_event_poll_hook(); \
     } while (0);
 
 #define MP_STATE_PORT MP_STATE_VM

bricks/nxt/mphalport.c

@@ -19,6 +19,9 @@
 #include <base/drivers/bt.h>
 #include "base/display.h"
 
+void pb_event_poll_hook_leave(void) {
+}
+
 void pb_stack_get_info(char **sstack, char **estack) {
     extern uint32_t __stack_start__;
     extern uint32_t __stack_end__;