use single constexpr definition instead of repeated expression.

cores/esp8266/Schedule.cpp

@@ -21,7 +21,6 @@
 #include "Schedule.h"
 #include "PolledTimeout.h"
 #include "interrupts.h"
-#include "coredecls.h"
 
 typedef std::function<void(void)> mSchedFuncT;
 struct scheduled_fn_t
@@ -50,6 +49,8 @@ static recurrent_fn_t* rLast = nullptr;
 // The target time for scheduling the next timed recurrent function 
 static decltype(micros()) rTarget;
 
+constexpr decltype(micros()) HALF_MAX_MICROS = ~static_cast<decltype(micros())>(0) >> 1;
+
 // Returns a pointer to an unused sched_fn_t,
 // or if none are available allocates a new one,
 // or nullptr if limit is reached
@@ -106,7 +107,7 @@ bool schedule_function(const std::function<void(void)>& fn)
 
 IRAM_ATTR // (not only) called from ISR
 bool schedule_recurrent_function_us(const std::function<bool(void)>& fn,
-    uint32_t repeat_us, const std::function<bool(void)>& alarm)
+    decltype(micros()) repeat_us, const std::function<bool(void)>& alarm)
 {
     assert(repeat_us < decltype(recurrent_fn_t::callNow)::neverExpires); //~26800000us (26.8s)
 
@@ -126,7 +127,7 @@ bool schedule_recurrent_function_us(const std::function<bool(void)>& fn,
     const auto now = micros();
     const auto itemRemaining = item->callNow.remaining();
     const int32_t remaining = rTarget - now;
-    if (!rFirst || (remaining > 0 && static_cast<uint32_t>(remaining) > itemRemaining))
+    if (!rFirst || (remaining > 0 && static_cast<decltype(micros())>(remaining) > itemRemaining))
     {
         rTarget = now + itemRemaining;
     }
@@ -144,17 +145,17 @@ bool schedule_recurrent_function_us(const std::function<bool(void)>& fn,
     return true;
 }
 
-uint32_t get_scheduled_recurrent_delay_us()
+decltype(micros()) get_scheduled_recurrent_delay_us()
 {
-    if (!rFirst) return ~static_cast<decltype(micros())>(0) >> 1;
+    if (!rFirst) return HALF_MAX_MICROS;
     // handle already expired rTarget.
     const int32_t remaining = rTarget - micros();
-    return (remaining > 0) ? static_cast<uint32_t>(remaining) : 0;
+    return (remaining > 0) ? static_cast<decltype(micros())>(remaining) : 0;
 }
 
-uint32_t get_scheduled_delay_us()
+decltype(micros()) get_scheduled_delay_us()
 {
-    return sFirst ? 0 : ~static_cast<decltype(micros())>(0) >> 1;
+    return sFirst ? 0 : HALF_MAX_MICROS;
 }
 
 void run_scheduled_functions()
@@ -223,7 +224,7 @@ void run_scheduled_recurrent_functions()
 
     // prevent scheduling of new functions during this run
     stop = rLast;
-    rTarget = micros() + (~static_cast<decltype(micros())>(0) >> 1);
+    rTarget = micros() + HALF_MAX_MICROS;
 
     do
     {
@@ -262,7 +263,7 @@ void run_scheduled_recurrent_functions()
             const auto now = micros();
             const auto currentRemaining = current->callNow.remaining();
             const int32_t remaining = rTarget - now;
-            if (remaining > 0 && static_cast<uint32_t>(remaining) > currentRemaining)
+            if (remaining > 0 && static_cast<decltype(micros())>(remaining) > currentRemaining)
             {
                 rTarget = now + currentRemaining;
             }

cores/esp8266/Schedule.h

@@ -22,6 +22,8 @@
 #include <functional>
 #include <stdint.h>
 
+#include "coredecls.h"
+
 #define SCHEDULED_FN_MAX_COUNT 32
 
 // The purpose of scheduled functions is to trigger, from SYS stack (like in
@@ -42,7 +44,7 @@
 // get_scheduled_recurrent_delay_us() is used by delay() to give a chance to
 // all recurrent functions to run per their timing requirement.
 
-uint32_t get_scheduled_recurrent_delay_us();
+decltype(micros()) get_scheduled_recurrent_delay_us();
 
 // scheduled functions called once:
 //
@@ -65,7 +67,7 @@ uint32_t get_scheduled_recurrent_delay_us();
 // values, viz. 0 in case of any pending scheduled functions, or a large delay time if
 // there is no function in the queue.
 
-uint32_t get_scheduled_delay_us();
+decltype(micros()) get_scheduled_delay_us();
 
 bool schedule_function (const std::function<void(void)>& fn);
 
@@ -93,7 +95,7 @@ void run_scheduled_functions();
 //   any remaining delay from repeat_us is disregarded, and fn is executed.
 
 bool schedule_recurrent_function_us(const std::function<bool(void)>& fn,
-    uint32_t repeat_us, const std::function<bool(void)>& alarm = nullptr);
+    decltype(micros()) repeat_us, const std::function<bool(void)>& alarm = nullptr);
 
 // Test recurrence and run recurrent scheduled functions.
 // (internally called at every `yield()` and `loop()`)

cores/esp8266/core_esp8266_main.cpp

@@ -174,7 +174,8 @@ bool esp_try_delay(const uint32_t start_ms, const uint32_t timeout_ms, const uin
     }
 
     // compute greatest delay interval with respect to scheduled recurrent functions
-    const uint32_t max_delay_ms = std::min(intvl_ms, get_scheduled_recurrent_delay_us() / 1000);
+    const uint32_t scheduled_recurrent_delay_ms = get_scheduled_recurrent_delay_us() / 1000UL;
+    const uint32_t max_delay_ms = std::min(intvl_ms, scheduled_recurrent_delay_ms);
 
     // recurrent scheduled functions will be called from esp_delay()->esp_suspend()
     esp_delay(std::min((timeout_ms - expired), max_delay_ms));