/*
 * sys_thread_exit.c - terminates the execution of current thread
 * 
 * Authors       Ghassan Almaless (2008,2009,2010,2011,2012)
 *               Alain Greiner (2016,2017)
 *
 * Copyright (c) UPMC Sorbonne Universites
 *
 * This file is part of ALMOS-MKH.
 *
 * ALMOS-MKH is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2.0 of the License.
 *
 * ALMOS-MKH is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <hal_types.h>
#include <hal_irqmask.h>
#include <thread.h>
#include <core.h>
#include <scheduler.h>
#include <printk.h>


////////////////////////////////////////
int sys_thread_exit( void * exit_value )
{
	thread_t  * this = CURRENT_THREAD;
    core_t    * core = this->core;
    reg_t       irq_state;

    // register the exit_value pointer in thread descriptor
    this->exit_value = exit_value;

    // enter the join loop to wait the join if thread is joinable
    if( (this->flags & THREAD_FLAG_DETACHED) == 0 )
    {
	    while( 1 ) 
	    {
            // take the lock protecting the flags
	        remote_spinlock_lock( XPTR( local_cxy, &this->flags_lock ) );

            // check the JOIN flag
            if( this->flags & THREAD_FLAG_JOIN )       // parent made a join
            {
                // unblock the parent thread
                thread_unblock( this->parent , THREAD_BLOCKED_JOIN );

                // release the lock protecting the flags
	            remote_spinlock_unlock( XPTR( local_cxy, &this->flags_lock ) );

                // exit while
                break;
            }
            else                                       // no join done by parent thread
            {
                // set the EXIT flag
                this->flags |= THREAD_FLAG_EXIT;

                // block this thread
                thread_block( this , THREAD_BLOCKED_EXIT );

                // release the lock protecting the flags
	            remote_spinlock_unlock( XPTR( local_cxy, &this->flags_lock ) );

                // deschedule
                sched_yield("waiting parent join");
            }     
        }
	}

	// Release FPU if required
	hal_disable_irq( &irq_state );
	if( core->fpu_owner == this )  core->fpu_owner = NULL;
	hal_restore_irq( irq_state );

	// suicide
    thread_kill( this );
	return 0;	

}  // end sys_thread_exit()