esp8266/esp_mphal: Add higher-level event polling function.

ets_event_poll() polls both system events and uPy pending exception.

esp8266/esp_mphal.c

@@ -30,6 +30,7 @@
 #include "uart.h"
 #include "esp_mphal.h"
 #include "user_interface.h"
+#include "ets_alt_task.h"
 #include "py/obj.h"
 #include "py/mpstate.h"
 
@@ -105,6 +106,15 @@ void mp_hal_set_interrupt_char(int c) {
     interrupt_char = c;
 }
 
+void ets_event_poll(void) {
+    ets_loop_iter();
+    if (MP_STATE_VM(mp_pending_exception) != NULL) {
+        mp_obj_t obj = MP_STATE_VM(mp_pending_exception);
+        MP_STATE_VM(mp_pending_exception) = MP_OBJ_NULL;
+        nlr_raise(obj);
+    }
+}
+
 void __assert_func(const char *file, int line, const char *func, const char *expr) {
     printf("assert:%s:%d:%s: %s\n", file, line, func, expr);
     nlr_raise(mp_obj_new_exception_msg(&mp_type_AssertionError,

esp8266/esp_mphal.h

@@ -39,5 +39,6 @@ uint32_t mp_hal_get_cpu_freq(void);
 #define UART_TASK_ID 0
 void uart_task_init();
 
+void ets_event_poll(void);
 
 #endif // _INCLUDED_MPHAL_H_