C C 實現協程API包括上下文切換

協程可以很方便在乙個執行緒中實現多個函式間的切換執行，如果某個函式需要等待，則可以切換到其他函式，這可以很大程度提高乙個執行緒的利用率，因此現在很流行；c++很多版本原生並沒有提供協程，但是由於c++支援內聯彙編，所以實現一套協程api並非難事，只要實現函式間的上下文切換，其他的就容易多了，上下文切換通常就是儲存當前函式的暫存器，由於是主動切換所以需要儲存的暫存器也就很少了，下面給出一種協程的實現方式：

coroutine.h

#ifndef m_coroutine_h
#define m_coroutine_h
//coroutine info
typedef struct
mcoroutine;
mcoroutine* alloc_co();
mcoroutine* pop_co();
bool createcoroutine(void (*task)(void*), void* args);
void schedule();
void runtask();
#define co_yield schedule();
#define print(str,...) printf(str##"\n",__va_args__)
#endif

coroutine.cpp

#include #include #include #include "coroutine.h"
//define the size of the coroutine stack
#define coroutine_stack_size 1024*1024*1 // 1m stack
#define max_coroutine 1000 // max coroutine num
//coroutine status flag
enum flags ;
std::listglobalcoroutinelist; // global coroutine list
static int coroutinerunningcount = 0; // the running count of coroutine
static mcoroutine cor_main = ; //main thread coroutine
static mcoroutine *currentcoroutine = &cor_main; //the current running coroutine
//assign a coroutine
mcoroutine *alloc_co() 
auto *co = new mcoroutine();
globalcoroutinelist.push_back(co);
return co;
}    globalcoroutinelist.push_back(co);
}// pop a coroutine from global coroutine list
mcoroutine *pop_co() 
mcoroutine *co;
co = globalcoroutinelist.front();
globalcoroutinelist.pop_front();
return co;
}//this function will be run for the first time, and the task will be called by this function
static void coroutine_startup(mcoroutine *coroutine) 
static void push_stack(unsigned int **stack_top_p_p, unsigned int val) 
static bool init_stack(mcoroutine *coroutine) 
static unsigned int id_num = 1;
static unsigned int get_id() 
bool createcoroutine(void (*task)(void *), void *args) 
void __fastcall release_coroutine(mcoroutine *coroutine)
__declspec(naked) void switch_context(mcoroutine *cur_coroutine, mcoroutine *dst_coroutine) 
}void schedule() 
switch(currentcoroutine->flag)
src_coroutine = currentcoroutine;
currentcoroutine = dst_coroutine;
switch_context(src_coroutine, dst_coroutine);
//print("switch_context over: src_coroutine:%d,dst_coroutine:%d", src_coroutine->id, dst_coroutine->id);
}void runtask()  while (coroutinerunningcount);
}

main.cpp

#include "coroutine.h"
#include void task(void* num) 
}int main() 
runtask();
return 0;
}

cmakelists.txt

cmake_minimum_required(version 3.16)
project(mythread)
set(cmake_cxx_standard 14)
add_executable(test00 main.cpp coroutine.cpp coroutine.h)

執行結果：

start... coroutine0 start... coroutine0_0 coroutine1 start... coroutine1_0 coroutine2 start... coroutine2_0 coroutine3 start... coroutine3_0 coroutine4 start... coroutine4_0 coroutine5 start... coroutine5_0 coroutine6 start... coroutine6_0 coroutine7 start... coroutine7_0 coroutine8 start... coroutine8_0 coroutine9 start... coroutine9_0 coroutine0_1 coroutine1_1

coroutine2_1

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C C 實現協程API包括上下文切換

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