IRAM attribute; small refactoring; runnableTasks array must be 1 element larger than max task #

Author: dok-net

examples/Callbacks/Callbacks.ino

@@ -4,6 +4,18 @@
 #include <CoopMutex.h>
 #include <BasicCoopTask.h>
 
+#if defined(ARDUINO_attiny)
+#define LED_BUILTIN 1
+
+struct DummySerial {
+    void print(const __FlashStringHelper* s = nullptr) {}
+    void println(const __FlashStringHelper* s = nullptr) {}
+    void println(long unsigned int) {}
+    void flush() {}
+};
+DummySerial Serial;
+#endif
+
 CoopTask<void>* blinkTask = nullptr;
 CoopTask<void>* switchTask = nullptr;
 
@@ -53,11 +65,13 @@ bool sleepCb()
 
 void setup()
 {
+#if !defined(ARDUINO_attiny)
     Serial.begin(74800);
     while (!Serial);
     delay(100);
     Serial.println();
     Serial.println(F("runTasks callback test"));
+#endif
 
     runCoopTasks(nullptr, delayCb, sleepCb);
     Serial.println(F("no tasks yet, sleepCb()?"));
@@ -78,7 +92,7 @@ void loop()
     Serial.println(F("B - both tasks delayed, delayCb(100)?"));
     yield();
     runCoopTasks(nullptr, delayCb, sleepCb);
-    Serial.println(F("C - blink task delayed, buzzer task sleeping, delayCb(4900)?"));
+    Serial.println(F("C - blink task delayed, switch task sleeping, delayCb(4900)?"));
     yield();
     runCoopTasks(nullptr, delayCb, sleepCb);
     Serial.println(F("D - both tasks sleeping, sleepCb()?"));

library.json

@@ -1,6 +1,6 @@
 {
     "name": "CoopTask",
-    "version": "3.6.0",
+    "version": "3.6.1",
     "keywords": [
       "multitasking", "timing"
     ],

library.properties

@@ -1,5 +1,5 @@
 name=CoopTask
-version=3.6.0
+version=3.6.1
 author=Dirk O. Kaar
 maintainer=Dirk O. Kaar <dok@dok-net.net>
 sentence=Portable C++ library for cooperative multitasking like Arduino Scheduler on ESP8266/ESP32, AVR, Linux, Windows

src/BasicCoopTask.h

@@ -101,10 +101,10 @@ template<class StackAllocator = CoopTaskStackAllocator> class BasicCoopTask : pu
     }
     /// Every task is entered into this list by scheduleTask(). It is removed when it exits
     /// or gets deleted.
-    static const std::array< std::atomic<BasicCoopTask* >, MAXNUMBERCOOPTASKS>& getRunnableTasks()
+    static const std::array< std::atomic<BasicCoopTask* >, MAXNUMBERCOOPTASKS + 1>& getRunnableTasks()
     {
         // this is safe to do because CoopTaskBase ctor is protected.
-        return reinterpret_cast<const std::array< std::atomic<BasicCoopTask* >, MAXNUMBERCOOPTASKS>&>(CoopTaskBase::getRunnableTasks());
+        return reinterpret_cast<const std::array< std::atomic<BasicCoopTask* >, MAXNUMBERCOOPTASKS + 1>&>(CoopTaskBase::getRunnableTasks());
     }
 protected:
     StackAllocator stackAllocator;

src/CoopSemaphore.cpp

@@ -127,21 +127,18 @@ bool CoopSemaphore::_wait(const bool withDeadline, const uint32_t ms)
             }
             if (selfFirst)
             {
-                if (!withDeadline) self->sleep(false);
                 selfFirst = false;
+                if (!withDeadline) self->sleep(false);
                 selfSuccess = true;
             }
             else if (pendingTask == self)
             {
-                if (selfSuccess)
-                {
-                    if (!stop) continue;
-                }
-                else
+                if (!selfSuccess)
                 {
                     if (!withDeadline) self->sleep(false);
                     return true;
                 }
+                if (!stop) continue;
             }
             else if (pendingTask)
             {
@@ -213,11 +210,8 @@ bool IRAM_ATTR CoopSemaphore::post()
     while (!value.compare_exchange_weak(val, val + 1)) {}
     pendingTask = pendingTask0.exchange(nullptr);
 #endif
-    if (pendingTask)
-    {
-        pendingTask->scheduleTask(true);
-    }
-    return true;
+    if (!pendingTask || !pendingTask->suspended()) return true;
+    return pendingTask->scheduleTask(true);
 }
 
 bool CoopSemaphore::setval(unsigned newVal)

src/CoopTaskBase.cpp

@@ -114,7 +114,7 @@ extern "C" {
 #endif // ESP32_FREERTOS
 }
 
-std::array< std::atomic<CoopTaskBase* >, CoopTaskBase::MAXNUMBERCOOPTASKS> CoopTaskBase::runnableTasks{};
+std::array< std::atomic<CoopTaskBase* >, CoopTaskBase::MAXNUMBERCOOPTASKS + 1> CoopTaskBase::runnableTasks {};
 std::atomic<size_t> CoopTaskBase::runnableTasksCount(0);
 
 CoopTaskBase* CoopTaskBase::current = nullptr;
@@ -174,11 +174,11 @@ bool CoopTaskBase::rescheduleTask(uint32_t repeat_us)
 }
 #endif
 
-bool CoopTaskBase::enrollRunnable()
+bool IRAM_ATTR CoopTaskBase::enrollRunnable()
 {
     bool enrolled = false;
     bool inserted = false;
-    for (size_t i = 0; i < CoopTaskBase::MAXNUMBERCOOPTASKS; ++i)
+    for (size_t i = 0; i < runnableTasks.size(); ++i)
     {
 #if !defined(ESP32) && defined(ARDUINO)
         InterruptLock lock;
@@ -235,7 +235,7 @@ void CoopTaskBase::delistRunnable()
 {
 #if !defined(ESP32) && defined(ARDUINO)
     InterruptLock lock;
-    for (size_t i = 0; i < CoopTaskBase::MAXNUMBERCOOPTASKS; ++i)
+    for (size_t i = 0; i < runnableTasks.size(); ++i)
     {
         if (runnableTasks[i].load() == this)
         {
@@ -245,7 +245,7 @@ void CoopTaskBase::delistRunnable()
         }
     }
 #else
-    for (size_t i = 0; i < CoopTaskBase::MAXNUMBERCOOPTASKS; ++i)
+    for (size_t i = 0; i < runnableTasks.size(); ++i)
     {
         CoopTaskBase* self = this;
         if (runnableTasks[i].compare_exchange_strong(self, nullptr))
@@ -646,7 +646,7 @@ CoopTaskBase* CoopTaskBase::self() noexcept
     const auto currentTaskHandle = xTaskGetCurrentTaskHandle();
     auto cur = current;
     if (cur && currentTaskHandle == cur->taskHandle) return cur;
-    for (size_t i = 0; i < CoopTaskBase::MAXNUMBERCOOPTASKS; ++i)
+    for (size_t i = 0; i < runnableTasks.size(); ++i)
     {
         cur = runnableTasks[i].load();
         if (cur && currentTaskHandle == cur->taskHandle) return cur;
@@ -804,11 +804,11 @@ void CoopTaskBase::dumpStack() const
 #endif
     while (pos < (taskStackSize + (FULLFEATURES ? sizeof(STACKCOOKIE) : 0)) / sizeof(STACKCOOKIE))
     {
+#ifndef ARDUINO_attiny
         auto* sp = &reinterpret_cast<unsigned*>(taskStackTop)[pos];
 
         // rough indicator: stack frames usually have SP saved as the second word
         bool looksLikeStackFrame = (sp[2] == reinterpret_cast<size_t>(&sp[4]));
-#ifndef ARDUINO_attiny
         ::printf(PSTR("%08x:  %08x %08x %08x %08x %c\n"),
             reinterpret_cast<size_t>(sp), sp[0], sp[1], sp[2], sp[3], looksLikeStackFrame ? '<' : ' ');
 #endif

src/CoopTaskBase.h

@@ -101,7 +101,8 @@ class CoopTaskBase
     jmp_buf env_yield;
 #endif
     static constexpr size_t MAXNUMBERCOOPTASKS = FULLFEATURES ? 32 : 8;
-    static std::array< std::atomic<CoopTaskBase* >, MAXNUMBERCOOPTASKS> runnableTasks;
+    // for lock-free insertion, must be one element larger than max task count
+    static std::array< std::atomic<CoopTaskBase* >, MAXNUMBERCOOPTASKS + 1> runnableTasks;
     static std::atomic<size_t> runnableTasksCount;
     static CoopTaskBase* current;
     bool init = false;
@@ -117,7 +118,7 @@ class CoopTaskBase
     static bool usingBuiltinScheduler;
     bool rescheduleTask(uint32_t repeat_us);
 #endif
-    bool enrollRunnable();
+    bool IRAM_ATTR enrollRunnable();
     void delistRunnable();
 
     void _exit() noexcept;
@@ -190,7 +191,7 @@ class CoopTaskBase
 #endif
     /// Every task is entered into this list by scheduleTask(). It is removed when it exits
     /// or gets deleted.
-    static const std::array< std::atomic<CoopTaskBase* >, MAXNUMBERCOOPTASKS>& getRunnableTasks()
+    static const decltype(runnableTasks)& getRunnableTasks()
     {
         return runnableTasks;
     }