本文为实现 SystemC 响应异步事件 解决方案。
应用场景：
SystemC是一个支持系统事务级、行为级建模的开源的C++ library；
我们将SystemC仿真的模拟叫做模拟器。在很多场景下，模拟器要保持alive，等待异步async事件，做出对应的处理。例如设计一个SystemC消费者模拟器，而生产者程序不属于SystemC仿真范畴，消费者模拟器需要一直保持等待，并在出现数据后进行处理。
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以上应用场景应当很常见，但是无论中文网站搜索、SystemC社区、谷歌搜索、Stack Overflow等，都没有合适的解决方案。笔者在综合了解相关问题及做了不少尝试后，给出了较为合适的解决方案。感兴趣的伙伴可以查看以下相关帖子：
Example of main thread controlling sub_thread(systemc module) to complete instructions - SystemC Language - Accellera Systems Initiative Forums
How to make a "single-only" sc_thread wait for a notify() from external host thread - SystemC Language - Accellera Systems Initiative Forums
https://workspace.accellera.org/document/dl/10932
async_request_update example - SystemC Language - Accellera Systems Initiative Forums
c++ - async_request_update() example in SystemC - Stack Overflow
这里是解决方案：
#include <systemc.h>
#include <pthread.h>
#include <unistd.h>
using namespace std;
class ThreadSafeEventIf : public sc_interface {
virtual void notify(sc_time delay = SC_ZERO_TIME) = 0;
virtual const sc_event &default_event(void) const = 0;
protected:
virtual void update(void) = 0;
};
class ThreadSafeEvent : public sc_prim_channel, public ThreadSafeEventIf {
public:
ThreadSafeEvent(const char *name = ""): event(name) {}
void notify(sc_time delay = SC_ZERO_TIME) {
this->delay = delay;
async_request_update();
}
const sc_event &default_event(void) const {
return event;
}
protected:
virtual void update(void) {
event.notify(delay);
}
sc_event event;
sc_time delay;
};
sc_event GenScEvent;
sc_event workingFinishEvent; // finish event
int workingFlag = 0; // maybe dnot need a lock
SC_MODULE(Foo) {
public:
SC_CTOR(Foo) {
SC_THREAD(main);
SC_METHOD(eventTriggered);
sensitive << threadSafeEvent;
dont_initialize();
SC_METHOD(stopTriggered);
sensitive << threadStopEvent;
dont_initialize();
}
private:
void main() { //extra forever thread to avoid simulation exit
while (true) {
usleep(0.05*1000*1000); // check if there is any instruction every one sec.
wait(SC_ZERO_TIME);
if(workingFlag){ // check working
wait(workingFinishEvent); // wait the working finish
}
usleep(0.05*1000*1000);
}
}
void eventTriggered() {
GenScEvent.notify();
}
void stopTriggered(){
sc_stop();
}
public:
ThreadSafeEvent threadSafeEvent;
ThreadSafeEvent threadStopEvent;
};
void* PollingThread(void* arg) {
int cnt = 0;
Foo *foo = (Foo*)(arg);
while (cnt<3) {
cnt++;
printf("[POLL]: %d: Before generating event from PollingThread \n", cnt);
usleep(3*1000*1000);
foo->threadSafeEvent.notify();
printf("[POLL]: %d: Event notified from PollingThread \n", cnt);
}
usleep(5*1000*1000);
foo->threadStopEvent.notify();
};
class sc_top : public sc_module {
private:
SC_HAS_PROCESS(sc_top);
public:
sc_top(sc_module_name name="SCTOP"): sc_module(name) {
SC_THREAD(processing_thread);
}
void processing_thread(){
int cnt =0;
while (true) {
printf("[PROC]: processing_thread called \n");
cout << "[PROC]: Wait GenScEvent time: " << sc_time_stamp();
wait(GenScEvent);
workingFlag = 1;
cnt++;
wait(10, SC_SEC); // advance simulation time
cout << "[PROC]: Process and Finish "<<cnt << " GenScEvent time: " << sc_time_stamp();
workingFinishEvent.notify();
workingFlag = 0;
}
}
};
int sc_main(int argc, char *argv[]) {
Foo foo("foo");
sc_top u_sc_top("u_sc_top");
pthread_t thread;
pthread_create(&thread, NULL, PollingThread, &foo);
sc_start();
return 0;
}
CMakeLists.txt
cmake_minimum_required (VERSION 3.5)
project (demo)
include_directories (${PROJECT_SOURCE_DIR}/include)
find_library(SystemC_LIB systemc HINTS ${PROJECT_SOURCE_DIR}/lib)
set (syc_LIST ${PROJECT_SOURCE_DIR}/src/syc.cpp)
add_executable (syc ${syc_LIST})
find_package(Threads REQUIRED)
target_link_libraries (syc ${SystemC_LIB} Threads::Threads)以上代码实现了 ：
1.主线程中运行 SystemC仿真模型，子线程中运行异步触发程序 （也可以根据自己的需要反过来，子线程中运行SystemC仿真模型，主线程运行触发程序。）
2.子线程每隔3秒触发一次SystemC仿真模型，主线程中的SystemC进行响应。
3.子线程主动触发三次之后，睡眠5秒，告知SystemC仿真结束。
结果：
SystemC 2.3.3-Accellera --- Mar 12 2024 15:33:04
Copyright (c) 1996-2018 by all Contributors,
ALL RIGHTS RESERVED
[POLL]: 1: Before generating event from PollingThread
[PROC]: processing_thread called
[PROC]: Wait GenScEvent time: 0 s[POLL]: 1: Event notified from PollingThread
[POLL]: 2: Before generating event from PollingThread
[PROC]: Process and Finish 1 GenScEvent time: 10 s[PROC]: processing_thread called
[PROC]: Wait GenScEvent time: 10 s[POLL]: 2: Event notified from PollingThread
[POLL]: 3: Before generating event from PollingThread
[PROC]: Process and Finish 2 GenScEvent time: 20 s[PROC]: processing_thread called
[PROC]: Wait GenScEvent time: 20 s[POLL]: 3: Event notified from PollingThread
[PROC]: Process and Finish 3 GenScEvent time: 30 s[PROC]: processing_thread called
[PROC]: Wait GenScEvent time: 30 s
Info: /OSCI/SystemC: Simulation stopped by user.
