📄 mbs.c
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/* TCC_Task_Priority Priority of specified task */
/* [TCT_Check_Stack] Stack checking function */
/* TCT_Control_To_System Transfer control to system */
/* TCT_Current_Thread Pickup current thread pointer*/
/* TCT_System_Protect Protect mailbox */
/* TCT_Unprotect Release protection */
/* */
/* INPUTS */
/* */
/* mailbox_ptr Mailbox control block pointer*/
/* message Pointer to message to send */
/* suspend Suspension option if full */
/* */
/* OUTPUTS */
/* */
/* NU_SUCCESS If service is successful */
/* NU_MAILBOX_FULL If mailbox is currently full */
/* NU_TIMEOUT If timeout on service expires*/
/* NU_MAILBOX_DELETED If mailbox is deleted during */
/* suspension */
/* NU_MAILBOX_RESET If mailbox is deleted during */
/* suspension */
/* */
/* HISTORY */
/* */
/* DATE REMARKS */
/* */
/* 03-01-1993 Created initial version 1.0 */
/* 04-19-1993 Verified version 1.0 */
/* 03-01-1994 Changed function interface to */
/* match the prototype, added */
/* register variable logic, */
/* optimized protection logic, */
/* resulting in version 1.1 */
/* */
/* 03-18-1994 Verified version 1.1 */
/* */
/*************************************************************************/
STATUS MBS_Broadcast_To_Mailbox(NU_MAILBOX *mailbox_ptr, VOID *message,
UNSIGNED suspend)
{
R1 MB_MCB *mailbox; /* Mailbox control block ptr */
MB_SUSPEND suspend_block; /* Allocate suspension block */
R2 MB_SUSPEND *suspend_ptr; /* Pointer to suspend block */
MB_SUSPEND *suspend_head; /* Pointer to suspend head */
MB_SUSPEND *next_suspend_ptr; /* Get before restarting task*/
STATUS preempt; /* Preemption flag */
R3 UNSIGNED *source_ptr; /* Pointer to source */
R4 UNSIGNED *destination_ptr; /* Pointer to destination */
TC_TCB *task; /* Task pointer */
STATUS status; /* Completion status */
/* Move input mailbox pointer into internal pointer. */
mailbox = (MB_MCB *) mailbox_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_BROADCAST_TO_MAILBOX_ID, (UNSIGNED) mailbox,
(UNSIGNED) message, (UNSIGNED) suspend);
#endif
/* Initialize the status as successful. */
status = NU_SUCCESS;
/* Protect against simultaneous access to the mailbox. */
TCT_System_Protect();
/* Determine if the mailbox is empty or full. */
if (mailbox -> mb_message_present)
{
/* Mailbox already has a message. Determine if suspension is
required. */
if (suspend)
{
/* Suspension is requested. */
/* Increment the number of tasks suspended on the mailbox. */
mailbox -> mb_tasks_waiting++;
#ifdef INCLUDE_PROVIEW
_RTProf_DumpMailBox(RT_PROF_BROADCAST_TO_MAILBOX,mailbox,RT_PROF_WAIT);
#endif
/* Setup the suspend block and suspend the calling task. */
suspend_ptr = &suspend_block;
suspend_ptr -> mb_mailbox = mailbox;
suspend_ptr -> mb_suspend_link.cs_next = NU_NULL;
suspend_ptr -> mb_suspend_link.cs_previous = NU_NULL;
suspend_ptr -> mb_message_area = (UNSIGNED *) message;
task = (TC_TCB *) TCT_Current_Thread();
suspend_ptr -> mb_suspended_task = task;
/* Determine if priority or FIFO suspension is associated with the
mailbox. */
if (mailbox -> mb_fifo_suspend)
{
/* FIFO suspension is required. Link the suspend block into
the list of suspended tasks on this mailbox. */
CSC_Place_On_List((CS_NODE **) &(mailbox ->mb_suspension_list),
&(suspend_ptr -> mb_suspend_link));
}
else
{
/* Get the priority of the current thread so the suspend block
can be placed in the appropriate place. */
suspend_ptr -> mb_suspend_link.cs_priority =
TCC_Task_Priority(task);
CSC_Priority_Place_On_List((CS_NODE **)
&(mailbox -> mb_suspension_list),
&(suspend_ptr -> mb_suspend_link));
}
/* Finally, suspend the calling task. Note that the suspension call
automatically clears the protection on the mailbox. */
TCC_Suspend_Task((NU_TASK *) task, NU_MAILBOX_SUSPEND,
MBC_Cleanup, suspend_ptr, suspend);
/* Pickup the return status. */
status = suspend_ptr -> mb_return_status;
}
else
{
/* Return a status of NU_MAILBOX_FULL because there is no
room in the mailbox for the message. */
status = NU_MAILBOX_FULL;
#ifdef INCLUDE_PROVIEW
_RTProf_DumpMailBox(RT_PROF_BROADCAST_TO_MAILBOX,mailbox,RT_PROF_FAIL);
#endif
}
}
else
{
/* Determine if a task is waiting on the mailbox. */
if (mailbox -> mb_suspension_list)
{
#ifdef INCLUDE_PROVIEW
_RTProf_DumpMailBox(RT_PROF_BROADCAST_TO_MAILBOX,mailbox,RT_PROF_OK);
#endif
/* At least one task is waiting on mailbox for a message. */
/* Save off the suspension list and and then clear out the
mailbox suspension. */
suspend_head = mailbox -> mb_suspension_list;
mailbox -> mb_suspension_list = NU_NULL;
/* Loop to wakeup all of the tasks waiting on the mailbox for
a message. */
suspend_ptr = suspend_head;
preempt = 0;
do
{
/* Setup the source and destination pointers. */
source_ptr = (UNSIGNED *) message;
destination_ptr = suspend_ptr -> mb_message_area;
/* Copy the message directly into the waiting task's
destination. */
*destination_ptr = *source_ptr;
*(destination_ptr + 1) = *(source_ptr + 1);
*(destination_ptr + 2) = *(source_ptr + 2);
*(destination_ptr + 3) = *(source_ptr + 3);
/* Setup the appropriate return value. */
suspend_ptr -> mb_return_status = NU_SUCCESS;
/* Move the suspend pointer along to the next block. */
next_suspend_ptr = (MB_SUSPEND *)
suspend_ptr -> mb_suspend_link.cs_next;
/* Wakeup each task waiting. */
preempt = preempt |
TCC_Resume_Task((NU_TASK *) suspend_ptr -> mb_suspended_task,
NU_MAILBOX_SUSPEND);
suspend_ptr = next_suspend_ptr;
} while (suspend_ptr != suspend_head);
/* Clear the number of tasks waiting counter of the mailbox. */
mailbox -> mb_tasks_waiting = 0;
/* Determine if a preempt condition is present. */
if (preempt)
/* Transfer control to the system if the resumed task function
detects a preemption condition. */
TCT_Control_To_System();
}
else
{
/* Mailbox is empty and no task is waiting. */
/* Setup the source and destination pointers. */
source_ptr = (UNSIGNED *) message;
destination_ptr = &(mailbox -> mb_message_area[0]);
/* Place the message in the mailbox. */
*destination_ptr = *source_ptr;
*(destination_ptr + 1) = *(source_ptr + 1);
*(destination_ptr + 2) = *(source_ptr + 2);
*(destination_ptr + 3) = *(source_ptr + 3);
/* Indicate that the mailbox has a message. */
mailbox -> mb_message_present = NU_TRUE;
#ifdef INCLUDE_PROVIEW
_RTProf_DumpMailBox(RT_PROF_BROADCAST_TO_MAILBOX,mailbox,RT_PROF_OK);
#endif
}
}
/* Release protection. */
TCT_Unprotect();
/* Return the completion status. */
return(status);
}
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