Nucleus

/*
 * This file contains the clone() function/system call.  It creates a new task,
 * and copies most of the attributes from the parent task into it.
 */

#include <sys/types.h>
#include <nucleus/task.h>

extern TaskQueue *readyQueue[];

/* Read the EIP */
static uintptr_t
read_eip(void)
{
	uintptr_t eip;
	asm volatile("movl 4(%%ebp), %0" : "=r" (eip));
	return eip;
}

/* Clone a task */
pid_t
clone(int flags)
{
	Task *parent = current, *child = new(&taskType), *tmp;
	pid_t tid = 0;

	/* After this, anything on the stack is desynchronised */
	child->pageDir = clone_dir();

	/* Split tasks here */
	uintptr_t esp, ebp, eip;
	eip = (uintptr_t) &&end;

	asm volatile("mov %%esp, %0" : "=r" (esp));
	asm volatile("mov %%ebp, %0" : "=r" (ebp));
	child->esp = esp;
	child->ebp = ebp;
	child->eip = eip;
	add_to_queue(readyQueue[child->priority], child);
	tid = child->tid;
	put(child);
end:
	return tid;
}