How to simulate thread interaction correctly

[YYF]

Hi，

Fellow experts, I'm having a problem with thread interaction. I design a model where thread_2 needs to wait for thread_1 to finish executing logic, and thread_1 needs to wait for thread_2 to finish executing logic before it can start executing.
I use the method of flag（wait_t_1 & wait_t_2） + wait(), but it seems that this method is a little silly, please tell me the correct design method, provided the code is as follows:

 

SC_MODULE(test)
{
  int a,b;
  
  bool wait_t_1 = true;
  bool wait_t_2 = false;
  
  void thread_1();
  void thread_2();

  SC_CTOR(test):
  {
    SC_CTHEAD(thread_1,clk.pos());
    SC_CTHEAD(thread_2,clk.pos());
  }
}

//-----------------------------------

void test::thread_1(){
  while(true){
    while(!wait_t_1) wait();
    
    for (int i = 0; i < 10000; i++) a++;
    
    wait_t_1 = false;
    wait_t_2 = true;
  }
}

void test::thread_2(){
  while(true){
    while(!wait_t_2) wait();
    
    for (int i = 0; i < 10000; i++) b++;
    
    wait_t_2 = false;
    wait_t_1 = true;
  }
}

 

[Eyck]

The prblem is the use of plain C datatypes for communication. Although SystemC simulates parallel exeution everything is executed in a sequential manner. When clk has a rising edge thread_1 as well as thread_2 have to be executed in the evalauation phase an the SystemC kernel decides in which order. Now if thread_1 executes first the value change of wait_t_2 is immediatley seen in thread_1 (and vice versa).

Therefore you need an element which defers the value update until the next evaluation phase. This element is a signal....

So you sould use sc_core::signal<bool> instead of a bool.