tx_ttsc.c

ThreadX优秀的硬实时操作系统.This Express Start Guide is designed to help you install and use ThreadX for the

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/*                                                                        */ 
/*            Copyright (c) 1996-2000 by Express Logic Inc.               */ 
/*                                                                        */ 
/*  This software is copyrighted by and is the sole property of Express   */ 
/*  Logic, Inc.  All rights, title, ownership, or other interests         */ 
/*  in the software remain the property of Express Logic, Inc.  This      */ 
/*  software may only be used in accordance with the corresponding        */ 
/*  license agreement.  Any unauthorized use, duplication, transmission,  */ 
/*  distribution, or disclosure of this software is expressly forbidden.  */ 
/*                                                                        */
/*  This Copyright notice may not be removed or modified without prior    */ 
/*  written consent of Express Logic, Inc.                                */ 
/*                                                                        */ 
/*  Express Logic, Inc. reserves the right to modify this software        */ 
/*  without notice.                                                       */ 
/*                                                                        */ 
/*  Express Logic, Inc.                                                   */
/*  11440 West Bernardo Court               [e-mail]         */
/*  Suite 366                               http://www.expresslogic.com   */
/*  San Diego, CA  92127                                                  */
/*                                                                        */
/**************************************************************************/


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/**                                                                       */ 
/** ThreadX Component                                                     */ 
/**                                                                       */
/**   Thread Control                                                      */
/**                                                                       */
/**************************************************************************/
/**************************************************************************/

#define TX_SOURCE_CODE


/* Include necessary system files.  */

#include    "tx_api.h"
#include    "tx_thr.h"
#include    "tx_tim.h"


/**************************************************************************/ 
/*                                                                        */ 
/*  FUNCTION                                               RELEASE        */ 
/*                                                                        */ 
/*    _tx_thread_time_slice_change                        PORTABLE C      */ 
/*                                                           3.0f         */ 
/*  AUTHOR                                                                */ 
/*                                                                        */ 
/*    William E. Lamie, Express Logic, Inc.                               */ 
/*                                                                        */ 
/*  DESCRIPTION                                                           */ 
/*                                                                        */ 
/*    This function processes thread time slice change requests.  The     */ 
/*    previous time slice is returned to the caller.  If the new request  */ 
/*    is made for an executing thread, it is also placed in the actual    */ 
/*    time-slice count-down variable.                                     */ 
/*                                                                        */ 
/*  INPUT                                                                 */ 
/*                                                                        */ 
/*    thread_ptr                            Pointer to thread             */ 
/*    new_time_slice                        New time slice                */ 
/*    old_time_slice                        Old time slice                */ 
/*                                                                        */ 
/*  OUTPUT                                                                */ 
/*                                                                        */ 
/*    status                                Service return status         */ 
/*                                                                        */ 
/*  CALLS                                                                 */ 
/*                                                                        */ 
/*    None                                                                */ 
/*                                                                        */ 
/*  CALLED BY                                                             */ 
/*                                                                        */ 
/*    Application Code                                                    */ 
/*                                                                        */ 
/*  RELEASE HISTORY                                                       */ 
/*                                                                        */ 
/*    DATE              NAME                      DESCRIPTION             */ 
/*                                                                        */ 
/*  12-31-1996     William E. Lamie         Initial Version 3.0           */ 
/*  11-11-1997     William E. Lamie         Modified comment(s),          */ 
/*                                            resulting in version 3.0b.  */ 
/*  01-01-1999     William E. Lamie         Modified comment(s),          */ 
/*                                            resulting in version 3.0e.  */ 
/*  11-01-1999     William E. Lamie         Modified comment(s),          */ 
/*                                            added logic to track events,*/ 
/*                                            resulting in version 3.0f.  */ 
/*                                                                        */ 
/**************************************************************************/ 
UINT    _tx_thread_time_slice_change(TX_THREAD *thread_ptr, ULONG new_time_slice,
                    ULONG *old_time_slice)
{

TX_INTERRUPT_SAVE_AREA


    /* Lockout interrupts while the thread is being resumed.  */
    TX_DISABLE

    /* Log this kernel call.  */
    TX_EL_THREAD_TIME_SLICE_CHANGE_INSERT

    /* Return the old time slice.  */
    *old_time_slice =  thread_ptr -> tx_new_time_slice;

    /* Setup the new time-slice.  */
    thread_ptr -> tx_time_slice =      new_time_slice;
    thread_ptr -> tx_new_time_slice =  new_time_slice;

    /* Determine if this thread is the currently executing thread.  */
    if (thread_ptr == _tx_thread_current_ptr)

        /* Yes, update the time-slice countdown variable.  */
        _tx_timer_time_slice =  new_time_slice;

    /* Restore interrupts.  */
    TX_RESTORE

    /* Return completion status.  */
    return(TX_SUCCESS);
}