tcs.c

test file nucleus source

/*************************************************************************/
/*                                                                       */
/*               Copyright Mentor Graphics Corporation 2002              */
/*                         All Rights Reserved.                          */
/*                                                                       */
/* THIS WORK CONTAINS TRADE SECRET AND PROPRIETARY INFORMATION WHICH IS  */
/* THE PROPERTY OF MENTOR GRAPHICS CORPORATION OR ITS LICENSORS AND IS   */
/* SUBJECT TO LICENSE TERMS.                                             */
/*                                                                       */
/*************************************************************************/

/*************************************************************************/
/*                                                                       */
/* FILE NAME                                               VERSION       */
/*                                                                       */
/*      tcs.c                                          Nucleus PLUS 1.14 */
/*                                                                       */
/* COMPONENT                                                             */
/*                                                                       */
/*      TC - Thread Control                                              */
/*                                                                       */
/* DESCRIPTION                                                           */
/*                                                                       */
/*      This file contains supplemental routines for the Thread Control  */
/*      component.                                                       */
/*                                                                       */
/* DATA STRUCTURES                                                       */
/*                                                                       */
/*      None                                                             */
/*                                                                       */
/* FUNCTIONS                                                             */
/*                                                                       */
/*      TCS_Change_Priority                 Change task's priority       */
/*      TCS_Change_Preemption               Change task's preemption     */
/*      TCS_Change_Time_Slice               Change task's time-slice     */
/*      TCS_Control_Signals                 Control signals              */
/*      TCS_Receive_Signals                 Receive signals              */
/*      TCS_Register_Signal_Handler         Register signal handler      */
/*      TCS_Send_Signals                    Send signals to a task       */
/*                                                                       */
/*                                                                       */
/* DEPENDENCIES                                                          */
/*                                                                       */
/*      cs_extr.h                           Common Service functions     */
/*      tc_extr.h                           Thread Control functions     */
/*      in_extr.h                           Initialization/Interrupt     */
/*                                            functions                  */
/*      tm_extr.h                           Timer Control function       */
/*      er_extr.h                           Error handling function      */
/*      hi_extr.h                           History functions            */
/*                                                                       */
/* HISTORY                                                               */
/*                                                                       */
/*        DATE                    REMARKS                                */
/*                                                                       */
/*      03-01-1994      Created initial version 1.1 from                 */
/*                      previous version of TCC.C                        */
/*                                                                       */
/*      03-18-1994      Verified version 1.1                             */
/*      04-04-1996      Modified TCS_Send_Signals,                       */
/*                      resulting in version 1.1+                        */
/*                      (spr 107)                                        */
/*      04-17-1996      updated to version 1.2                           */
/*      03-24-1998      Released version 1.3.                            */
/*      03-26-1999      Released 1.11m (new release                      */
/*                        numbering scheme)                              */
/*      04-17-2002      Released version 1.13m                           */
/*      11-07-2002      Released version 1.14                            */
/*************************************************************************/
#define         NU_SOURCE_FILE


#include        "cs_extr.h"                 /* Common service functions  */
#include        "tc_extr.h"                 /* Thread control functions  */
#include        "in_extr.h"                 /* Initialization/Interrupt  */
                                            /*   functions               */
#include        "tm_extr.h"                 /* Timer control functions   */
#include        "er_extr.h"                 /* Error handling function   */
#include        "hi_extr.h"                 /* History functions         */
#include        "profiler.h"                /* ProView interface         */


/* Define external inner-component global data references.  */

extern CS_NODE         *TCD_Created_Tasks_List;
extern TC_TCB          *TCD_Priority_List[TC_PRIORITIES];
extern UNSIGNED         TCD_Priority_Groups;
extern DATA_ELEMENT     TCD_Sub_Priority_Groups[TC_MAX_GROUPS];
extern UNSIGNED_CHAR    TCD_Lowest_Set_Bit[];
extern INT              TCD_Highest_Priority;
extern TC_TCB          *TCD_Execute_Task;
extern VOID            *TCD_Current_Thread;
extern TC_PROTECT       TCD_System_Protect;
extern INT              TMD_Time_Slice_State;



/* Define external inner-component function calls that are not available to
   other components.  */

VOID            TCT_Build_Signal_Frame(TC_TCB *task_ptr);
VOID            TCT_Protect_Switch(TC_TCB *task);
VOID            TCT_Signal_Exit(VOID);


/* Define internal function calls.  */

VOID            TCC_Signal_Shell(VOID);


/*************************************************************************/
/*                                                                       */
/* FUNCTION                                                              */
/*                                                                       */
/*      TCS_Change_Priority                                              */
/*                                                                       */
/* DESCRIPTION                                                           */
/*                                                                       */
/*      This function changes the priority of the specified task.  The   */
/*      priority of a suspended or a ready task can be changed.  If the  */
/*      new priority necessitates a context switch, control is           */
/*      transferred back to the system.                                  */
/*                                                                       */
/* CALLED BY                                                             */
/*                                                                       */
/*      Application                                                      */
/*      TCSE_Change_Priority                Error checking shell         */
/*                                                                       */
/* CALLS                                                                 */
/*                                                                       */
/*      [HIC_Make_History_Entry]            Make entry in history log    */
/*      [TCT_Check_Stack]                   Stack checking function      */
/*      TCT_Control_To_System               Transfer control to system   */
/*      TCT_Protect                         Protect scheduling data      */
/*      TCT_Set_Execute_Task                Set TCD_Execute_Task pointer */
/*      TCT_Unprotect                       Release protection of data   */
/*                                                                       */
/* INPUTS                                                                */
/*                                                                       */
/*      task_ptr                            Task control block pointer   */
/*      new_priority                        New priority for task        */
/*                                                                       */
/* OUTPUTS                                                               */
/*                                                                       */
/*      old_priority                        Original task priority       */
/*                                                                       */
/* HISTORY                                                               */
/*                                                                       */
/*         DATE                    REMARKS                               */
/*                                                                       */
/*      03-01-1993      Created initial version 1.0                      */
/*      04-19-1993      Verified version 1.0                             */
/*      03-01-1994      Modified function interface,                     */
/*                      added register optimizations,                    */
/*                      modified protection logic,                       */
/*                      resulting in version 1.1                         */
/*                                                                       */
/*      03-18-1994      Verified version 1.1                             */
/*                                                                       */
/*      10-4-1999       Bug fixes - return if new                        */
/*                      priority equals old priority                     */
/*                      and don't move the head pointer                  */
/*                      unless the head node is changing                 */
/*************************************************************************/
OPTION   TCS_Change_Priority(NU_TASK *task_ptr, OPTION new_priority)
{

R1 TC_TCB      *task;                       /* Task control block ptr    */
R2 TC_TCB      *head;                       /* Head list pointer         */
R3 INT          index;                      /* Working index variable    */
OPTION          old_priority;               /* Previous priority of task */
DATA_ELEMENT    temp;                       /* Temporary variable        */
NU_SUPERV_USER_VARIABLES

    /* Switch to supervisor mode */
    NU_SUPERVISOR_MODE();

    /* Move task control block pointer into internal pointer.  */
    task =  (TC_TCB *) task_ptr;


#ifdef  NU_ENABLE_STACK_CHECK

    /* Call stack checking function to check for an overflow condition.  */
    TCT_Check_Stack();

#endif

#ifdef  NU_ENABLE_HISTORY

    /* Make an entry that corresponds to this function in the system history
       log.  */
    HIC_Make_History_Entry(NU_CHANGE_PRIORITY_ID, (UNSIGNED) task,
                                        (UNSIGNED) new_priority, (UNSIGNED) 0);

#endif

    /* Protect against multiple access to the scheduling list.  */
    TCT_Protect(&TCD_System_Protect);

    /* Save the old priority of the task.  */
    old_priority =  task -> tc_priority;


    /* BUG FIX  this should probably go into an error checking routine instead of here  */
    if (!(task -> tc_priority == new_priority))
    {


       /* Check to see if the task is currently ready.  */
       if (task -> tc_status == NU_READY)
       {

           /* Remove the task from the ready list.  */

           /* Determine if the task is the only one on the list.  */
           if (task -> tc_ready_next == task)
           {

               /* Only task on the list.  Clear the task's pointers and
               clear the entry in the priority table.  */
               task -> tc_ready_next =        NU_NULL;
               task -> tc_ready_previous =    NU_NULL;
               *(task -> tc_priority_head) =  NU_NULL;

               /* Clear the sub-priority group.  */
               *(task -> tc_sub_priority_ptr) =
                  *(task -> tc_sub_priority_ptr) & ~(task -> tc_sub_priority);

               /* Determine if the main priority group needs to be cleared.
                  This is only true if there are no other bits set in this
                  sub-priority.  */
               if (*(task -> tc_sub_priority_ptr) == 0)

                   /* Clear the main priority group bit.  */
                   TCD_Priority_Groups =
                       TCD_Priority_Groups & ~(task -> tc_priority_group);
           }
           else
           {

               /* Not the only task ready at the same priority level.  */

               /* Remove from the linked-list.  */
               (task -> tc_ready_previous) -> tc_ready_next =
                                                 task -> tc_ready_next;
               (task -> tc_ready_next) -> tc_ready_previous =
                                                 task -> tc_ready_previous;



               /* Update the head pointer.  */
               /* BUG FIX - update head if head is changing priority - leave
                  it alone otherwise! */
               if(*(task -> tc_priority_head) ==  task )
               *(task -> tc_priority_head) =  task -> tc_ready_next;

               /* Clear the next and previous pointers.  */
               task -> tc_ready_next =        NU_NULL;
               task -> tc_ready_previous =    NU_NULL;
           }

           /* Now add in the task at the new priority.  */
           task -> tc_priority =  new_priority;

           /* Build the other priority information.  */
           task -> tc_priority =      new_priority;
           task -> tc_priority_head = &(TCD_Priority_List[new_priority]);
           task -> tc_sub_priority =  (DATA_ELEMENT) (1 << (new_priority & 7));
           task -> tc_priority_group =   ((UNSIGNED) 1) << (new_priority >> 3);
           task -> tc_sub_priority_ptr =
                   &(TCD_Sub_Priority_Groups[(new_priority >> 3)]);

#ifdef INCLUDE_PROVIEW
        _RTProf_DumpTask(task,RT_PROF_CHANGE_PRIORITY);
#endif
           /* Link the task into the new priority list.  */
           head =  *(task -> tc_priority_head);

           /* Determine if the list is non-empty.  */
           if (head)
           {

               /* Add the TCB to the end of the ready list.  */
               task -> tc_ready_previous =      head -> tc_ready_previous;
               (task -> tc_ready_previous) -> tc_ready_next =  task;
               task -> tc_ready_next =          head;
               (task -> tc_ready_next) -> tc_ready_previous =  task;