basic-coroutine.cpp

#include <setjmp.h>

#define SET_STACK(stack) asm("movl %0, %%esp": : "r"(stack))
//#define SET_STACK(stack) asm("mov %0, sp" : : "r"(stack));

template <typename FnctrT>
struct coroutine {
	int operator ()() {
		if (volatile int n = setjmp(jb_outer)) {
			return n;
		} else {
			if (inited) {
				longjmp(jb_inner, 1);
			} else {
				SET_STACK(stack);
				longjmp(jb_outer, static_cast<FnctrT *>(this)->main());
			}
		}
	}
	coroutine(void *st) {
		stack = st;
		inited = false;
		exited = false;
	}
	bool exitp() const { return exited; }
protected:
	jmp_buf jb_outer;
	jmp_buf jb_inner;
	void *stack;
	bool inited;
	bool exited;
	void exit(volatile int code) {
		exited = true;
		setjmp(jb_inner);
		longjmp(jb_outer, code);
	}
	void yield(volatile int n) {
		inited = true;
		if (setjmp(jb_inner)) {
			return;
		} else {
			longjmp(jb_outer, n);
		}
		
	}
	~coroutine(){}
};

struct myroutine: coroutine<myroutine> {
	myroutine(void *stack): coroutine<myroutine>(stack) { }
	int main() {
		for (int i=1; i<=9; ++i) {
			for (int j=1; j<=9; ++j) yield(i*j);
		}
		exit(0);
	}
};

#include <stdio.h>

unsigned char stack[1024];

int main() {
	myroutine r(&stack[1020]);
	while (!r.exitp()) printf("%d\n", r());
}