Add wait loop at the end of mode, refactor can_yield (#6721)

* Add wait loop at the end of mode, refactor can_yield

* fix mock build

Author: devyte

cores/esp8266/core_esp8266_main.cpp

@@ -90,6 +90,9 @@ void preloop_update_frequency() {
 #endif
 }
 
+extern "C" bool can_yield() {
+  return cont_can_yield(g_pcont);
+}
 
 static inline void esp_yield_within_cont() __attribute__((always_inline));
 static void esp_yield_within_cont() {
@@ -98,7 +101,7 @@ static void esp_yield_within_cont() {
 }
 
 extern "C" void esp_yield() {
-    if (cont_can_yield(g_pcont)) {
+    if (can_yield()) {
         esp_yield_within_cont();
     }
 }
@@ -109,7 +112,7 @@ extern "C" void esp_schedule() {
 }
 
 extern "C" void __yield() {
-    if (cont_can_yield(g_pcont)) {
+    if (can_yield()) {
         esp_schedule();
         esp_yield_within_cont();
     }
@@ -121,7 +124,7 @@ extern "C" void __yield() {
 extern "C" void yield(void) __attribute__ ((weak, alias("__yield")));
 
 extern "C" void optimistic_yield(uint32_t interval_us) {
-    if (cont_can_yield(g_pcont) &&
+    if (can_yield() &&
         (system_get_time() - s_micros_at_task_start) > interval_us)
     {
         yield();

cores/esp8266/coredecls.h

@@ -14,6 +14,7 @@ extern "C" {
 
 extern bool timeshift64_is_set;
 
+bool can_yield();
 void esp_yield();
 void esp_schedule();
 void tune_timeshift64 (uint64_t now_us);