Tiny Threads - Tiny Multitasking Threads for Microcontrollers

by: Regulus Berdin

• Idea based on http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html.
• Only 1 byte RAM needed per thread.
• Very small overhead context switching.

Limitations:

• Maximum 254 lines per thread.
• Thread context switching will not work within a switch block.

Usage example:

     TT_DEF(1)
   {
      TT_BEGIN(1);
    while (1)
      {
         ...
         TT_SWITCH(1);
         ...
         ...
         TT_WAIT_UNTIL(1,keypress);
      }
      TT_END(1);
   }
 
   TT_DEF(LED_TASK)
   {
       TT_BEGIN(LED_TASK);
       while (1)
       {
           LedOn();
           delay=DELAY_1_SECOND;
           TT_WAIT_UNTIL(LED_TASK,delay==0);
           LedOff();
           delay=DELAY_1_SECOND;
           TT_WAIT_UNTIL(LED_TASK,delay==0);
       }
       TT_END(LED_TASK);
   }
  
   void main(void)
   {
       ...
       ...
       while(1)
       {
           TT_SCHED(1);
           TT_SCHED(LED_TASK);
       }
   }


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