linux_misc.c

eCos1.31版

//=============================================================================
//
//      linux_misc.c
//
//      Misc code for the Linux HAL
//
//=============================================================================
//####COPYRIGHTBEGIN####
//                                                                          
// -------------------------------------------                              
// The contents of this file are subject to the Red Hat eCos Public License 
// Version 1.1 (the "License"); you may not use this file except in         
// compliance with the License.  You may obtain a copy of the License at    
// http://www.redhat.com/                                                   
//                                                                          
// Software distributed under the License is distributed on an "AS IS"      
// basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.  See the 
// License for the specific language governing rights and limitations under 
// the License.                                                             
//                                                                          
// The Original Code is eCos - Embedded Configurable Operating System,      
// released September 30, 1998.                                             
//                                                                          
// The Initial Developer of the Original Code is Red Hat.                   
// Portions created by Red Hat are                                          
// Copyright (C) 1998, 1999, 2000 Red Hat, Inc.                             
// All Rights Reserved.                                                     
// -------------------------------------------                              
//                                                                          
//####COPYRIGHTEND####
//=============================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):   asl
// Contributors:asl
// Date:        1999-09-23
// Purpose:     Misc functions for the Linux HAL
// Description: Misc functions for the Linux HAL
//
//####DESCRIPTIONEND####
//
//=============================================================================

#include <pkgconf/hal.h>
#include <cyg/infra/cyg_type.h>         // base types

#ifdef CYGPKG_KERNEL
# include <pkgconf/kernel.h>
#endif

// This is not correct, but it will do.
externC int cyg_hal_sys__newselect(int,int,int,int,int);

// Here we define an action to do in the idle thread. For the
// synthetic architecture it makes no sense to spin eating processor
// time that other processes could make use of. Instead we call
// select. The itimer will still go off and kick the scheduler back
// into life so giving up an escape path from the select. There is one
// catch-22: this only works if we are using the real time clock for
// itimer, not the virtual clock.  The virtual clock works on time the
// process actually uses. When it's sitting in the select it does not
// use any time, so the timer does not expire!  Also we don't do a
// select when the THREAD_YIELD option is in use since we want the
// yield to be called regularly.

void
hal_idle_thread_action(cyg_uint32 loop_count)
{
#ifndef CYGIMP_IDLE_THREAD_YIELD
#ifdef CYGSEM_HAL_I386_LINUX_REAL_TIME
    cyg_hal_sys__newselect(0,0,0,0,0);
#endif
#endif
}