routine.c

虚拟地址空间基于文件的操作系统

#include"kernel.h"

#define SET_THREAD_PARAMETER					\
{								\
	int m_id,s_id;						\
								\
	current.return_stack_top=current.t->return_stack_top;	\
	current.rt=&(current.t->return_stack[			\
		current.return_stack_top-1]);			\
	current.env=&(current.rt->environment);			\
	m_id=current.rt->physical_block.memory_id;		\
	s_id=current.rt->physical_block.stack_block_id;		\
	if((m_id>=0)&&(s_id>=0))				\
		current.par=(union system_call_parameter *)	\
			get_block_base(m_id,s_id);		\
	else							\
		current.par=(union system_call_parameter *)	\
		(kernel_get_thread_parameter(			\
			current.thread_id));			\
								\
}

void system_call()
{
	int sem_id,return_value,p_id;

	for(;;){
		current.cpu_id=get_virtual_cpu();
		current.cpu_info=&(os->virtual_cpu.used_cpu[
			current.cpu_id]);
		if((current.thread_id=(current.cpu_info->thread_id))<0){
			current.env=(struct thread_environment *)0;
			do_idle();
			switch_virtual_cpu();
			continue;
		}
		current.t=&(os->thread[current.thread_id]);
		SET_THREAD_PARAMETER;
		if(((int)(current.env->point.function))==0)
			return_value=1;
		else{
			if(lock_os_kernel()){
				switch_virtual_cpu();
				continue;
			}
			return_value=current.env->point.function();
			unlock_os_kernel();
			RESET_THREAD_PARAMETER(*(current.env));
			if(return_value==0){
				switch_virtual_cpu();
				continue;
			}
		}

		if(current.t->state!=RUN)
			continue;
		if((current.return_stack_top)
			!=(current.t->return_stack_top))
				SET_THREAD_PARAMETER;
	
		if(!(current.rt->process_p_flag))
			break;
		p_id=current.rt->current_process;
		if((sem_id=os->process[p_id].semaphore)<=0)
			break;
		if(lock_os_kernel()){
			switch_virtual_cpu();
			continue;
		}
		return_value=p(current.thread_id,sem_id,TRUE,FALSE,
			&(os->semaphore[sem_id].capability));
		unlock_os_kernel();
		if(return_value<0)
			break;
		current.rt->process_p_flag=FALSE;
		if(current.t->state==RUN)
			break;
	}

	if(!(COMPARE_THREAD_PHYSICAL_BLOCK((current.rt->physical_block),
		(current.cpu_info->last.physical_block))))
	{
		notify_physical_block_switch(current.thread_id,
			&(current.rt->physical_block));
		COPY_THREAD_PHYSICAL_BLOCK((current.rt->physical_block),
			(current.cpu_info->last.physical_block));
	}

	if(((current.cpu_info->last.thread_id)!=current.thread_id)||
		((current.cpu_info->last.process_id)
		!=(current.rt->current_process)))
	{
		notify_switch(current.thread_id);
		current.cpu_info->last.thread_id=current.thread_id;
		current.cpu_info->last.process_id
			=current.rt->current_process;
	}

	return ;
}