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view src/nucleus/qus.c @ 11:12ed2291fb67
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| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Fri, 16 Oct 2020 07:04:58 +0000 |
| parents | 4e78acac3d88 |
| children |
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/*************************************************************************/ /* */ /* 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 */ /* */ /* qus.c Nucleus PLUS 1.14 */ /* */ /* COMPONENT */ /* */ /* QU - Queue Management */ /* */ /* DESCRIPTION */ /* */ /* This file contains supplemental routines for the Queue */ /* Management component. */ /* */ /* DATA STRUCTURES */ /* */ /* None */ /* */ /* FUNCTIONS */ /* */ /* QUS_Reset_Queue Reset a queue */ /* QUS_Send_To_Front_Of_Queue Send message to queue's front*/ /* QUS_Broadcast_To_Queue Broadcast a message to queue */ /* */ /* DEPENDENCIES */ /* */ /* cs_extr.h Common Service functions */ /* tc_extr.h Thread Control functions */ /* qu_extr.h Queue functions */ /* hi_extr.h History functions */ /* */ /* HISTORY */ /* */ /* DATE REMARKS */ /* */ /* 03-01-1994 Created initial version 1.1 from */ /* routines originally in core */ /* */ /* 03-18-1994 Verified version 1.1 */ /* 04-17-1996 updated to version 1.2 */ /* 02-04-1998 Corrected SPR434 resulting in */ /* version 1.2a. */ /* 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 "qu_extr.h" /* Queue functions */ #include "hi_extr.h" /* History functions */ #include "profiler.h" /* ProView interface */ /* Define internal component function prototypes. */ VOID QUC_Cleanup(VOID *information); /*************************************************************************/ /* */ /* FUNCTION */ /* */ /* QUS_Reset_Queue */ /* */ /* DESCRIPTION */ /* */ /* This function resets the specified queue back to the original */ /* state. Any messages in the queue are discarded. Also, any */ /* tasks currently suspended on the queue are resumed with the */ /* reset status. */ /* */ /* CALLED BY */ /* */ /* Application */ /* QUSE_Reset_Queue Error checking shell */ /* */ /* CALLS */ /* */ /* [HIC_Make_History_Entry] Make entry in history log */ /* TCC_Resume_Task Resume a suspended task */ /* [TCT_Check_Stack] Stack checking function */ /* TCT_Control_To_System Transfer control to system */ /* TCT_System_Protect Protect queue data structures*/ /* TCT_Unprotect Release protection */ /* */ /* INPUTS */ /* */ /* queue_ptr Queue control block pointer */ /* */ /* OUTPUTS */ /* */ /* NU_SUCCESS */ /* */ /* HISTORY */ /* */ /* DATE REMARKS */ /* */ /* 03-01-1993 Created initial version 1.0 */ /* 04-19-1993 Verified version 1.0 */ /* 03-01-1994 Changed function interfaces to */ /* match those in prototype, */ /* added register options, changed */ /* protection logic to reduce */ /* overhead, fixed read and write */ /* pointers to both point at the */ /* start, resulting in version 1.1 */ /* */ /* 03-18-1994 Verified version 1.1 */ /* 02-04-1998 Corrected SPR434. */ /* */ /*************************************************************************/ STATUS QUS_Reset_Queue(NU_QUEUE *queue_ptr) { R1 QU_QCB *queue; /* Queue control block ptr */ QU_SUSPEND *suspend_ptr; /* Suspend block pointer */ QU_SUSPEND *next_ptr; /* Next suspend block pointer*/ STATUS preempt; /* Status for resume call */ NU_SUPERV_USER_VARIABLES /* Move input queue pointer into internal pointer. */ queue = (QU_QCB *) queue_ptr; /* Switch to supervisor mode */ NU_SUPERVISOR_MODE(); #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_RESET_QUEUE_ID, (UNSIGNED) queue, (UNSIGNED) 0, (UNSIGNED) 0); #endif /* Protect against access to the queue. */ TCT_System_Protect(); /* Pickup the suspended task suspension list. */ suspend_ptr = queue -> qu_suspension_list; /* Walk the chain task(s) currently suspended on the queue. */ preempt = 0; while (suspend_ptr) { /* Resume the suspended task. Insure that the status returned is NU_QUEUE_RESET. */ suspend_ptr -> qu_return_status = NU_QUEUE_RESET; /* Point to the next suspend structure in the link. */ next_ptr = (QU_SUSPEND *) (suspend_ptr -> qu_suspend_link.cs_next); /* Resume the specified task. */ preempt = preempt | TCC_Resume_Task((NU_TASK *) suspend_ptr -> qu_suspended_task, NU_QUEUE_SUSPEND); /* Determine if the next is the same as the head pointer. */ if (next_ptr == queue -> qu_suspension_list) /* Clear the suspension pointer to signal the end of the list traversal. */ suspend_ptr = NU_NULL; else /* Position the suspend pointer to the next suspend block. */ suspend_ptr = next_ptr; } /* Pickup the urgent message suspension list. */ suspend_ptr = queue -> qu_urgent_list; /* Walk the chain task(s) currently suspended on the queue. */ while (suspend_ptr) { /* Resume the suspended task. Insure that the status returned is NU_QUEUE_RESET. */ suspend_ptr -> qu_return_status = NU_QUEUE_RESET; /* Point to the next suspend structure in the link. */ next_ptr = (QU_SUSPEND *) (suspend_ptr -> qu_suspend_link.cs_next); /* Resume the specified task. */ preempt = preempt | TCC_Resume_Task((NU_TASK *) suspend_ptr -> qu_suspended_task, NU_QUEUE_SUSPEND); /* Determine if the next is the same as the head pointer. */ if (next_ptr == queue -> qu_urgent_list) /* Clear the suspension pointer to signal the end of the list traversal. */ suspend_ptr = NU_NULL; else /* Position suspend pointer to the next suspend block. */ suspend_ptr = next_ptr; } /* Initialize various elements of the queue. */ queue -> qu_available = queue -> qu_end - queue -> qu_start; queue -> qu_messages = 0; queue -> qu_read = queue -> qu_start; queue -> qu_write = queue -> qu_start; queue -> qu_tasks_waiting = 0; queue -> qu_suspension_list = NU_NULL; queue -> qu_urgent_list = NU_NULL; #ifdef INCLUDE_PROVIEW _RTProf_DumpQueue(RT_PROF_RESET_QUEUE,queue,RT_PROF_OK); #endif /* Determine if preemption needs to occur. */ if (preempt) /* Transfer control to system to facilitate preemption. */ TCT_Control_To_System(); /* Release protection against access to the queue. */ TCT_Unprotect(); /* Return to user mode */ NU_USER_MODE(); /* Return a successful completion. */ return(NU_SUCCESS); } /*************************************************************************/ /* */ /* FUNCTION */ /* */ /* QUS_Send_To_Front_Of_Queue */ /* */ /* DESCRIPTION */ /* */ /* This function sends a message to the front of the specified */ /* message queue. The message length is determined by the caller. */ /* If there are any tasks suspended on the queue for a message, the */ /* message is copied into the message area of the first waiting */ /* task and that task is resumed. If there is enough room in the */ /* queue, the message is copied in front of all other messages. */ /* If there is not enough room in the queue, suspension of the */ /* caller is possible. */ /* */ /* CALLED BY */ /* */ /* Application */ /* QUSE_Send_To_Front_Of_Queue Error checking shell */ /* */ /* CALLS */ /* */ /* CSC_Place_On_List Place on suspend list */ /* CSC_Remove_From_List Remove from suspend list */ /* [HIC_Make_History_Entry] Make entry in history log */ /* TCC_Resume_Task Resume a suspended task */ /* TCC_Suspend_Task Suspend calling 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 queue */ /* TCT_Unprotect Release protection */ /* */ /* INPUTS */ /* */ /* queue_ptr Queue control block pointer */ /* message Pointer to message to send */ /* size Size of message to send */ /* suspend Suspension option if full */ /* */ /* OUTPUTS */ /* */ /* NU_SUCCESS If service is successful */ /* NU_QUEUE_FULL If queue is currently full */ /* NU_TIMEOUT If timeout on service expires*/ /* NU_QUEUE_DELETED If queue was deleted during */ /* suspension */ /* NU_QUEUE_RESET If queue was reset 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 interfaces to */ /* match those in prototype, */ /* added register options, changed */ /* protection logic to reduce */ /* overhead, optimized copy loop, */ /* resulting in version 1.1 */ /* */ /* 03-18-1994 Verified version 1.1 */ /* */ /*************************************************************************/ STATUS QUS_Send_To_Front_Of_Queue(NU_QUEUE *queue_ptr, VOID *message, UNSIGNED size, UNSIGNED suspend) { R1 QU_QCB *queue; /* Queue control block ptr */ QU_SUSPEND suspend_block; /* Allocate suspension block */ QU_SUSPEND *suspend_ptr; /* Pointer to suspend block */ R3 UNSIGNED_PTR source; /* Pointer to source */ R4 UNSIGNED_PTR destination; /* Pointer to destination */ UNSIGNED copy_size; /* Partial copy size */ R2 INT i; /* Working counter */ TC_TCB *task; /* Task pointer */ STATUS preempt; /* Preempt flag */ STATUS status; /* Completion status */ NU_SUPERV_USER_VARIABLES /* Switch to supervisor mode */ NU_SUPERVISOR_MODE(); /* Move input queue pointer into internal pointer. */ queue = (QU_QCB *) queue_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_SEND_TO_FRONT_OF_QUEUE_ID, (UNSIGNED) queue, (UNSIGNED) message, (UNSIGNED) size); #endif /* Initialize the status as successful. */ status = NU_SUCCESS; /* Protect against simultaneous access to the queue. */ TCT_System_Protect(); /* Determine if an extra word of overhead needs to be added to the calculation. */ if (queue -> qu_fixed_size) /* No overhead. */ i = 0; else { /* Variable messages have one additional word of overhead. */ i = 1; /* Make special check to see if a suspension needs to be forced for a variable length message. */ if ((queue -> qu_suspension_list) && (queue -> qu_messages)) { /* Pickup task control block pointer. */ task = (TC_TCB *) TCT_Current_Thread(); /* Now we know that there are other task(s) are suspended trying to send a variable length message. Determine whether or not a suspension should be forced. */ if ((queue -> qu_fifo_suspend) || (suspend == NU_NO_SUSPEND) || ((queue -> qu_suspension_list) -> qu_suspend_link.cs_priority <= TCC_Task_Priority(task))) /* Bump the computed size to avoid placing the new variable length message ahead of the suspended tasks. */ i = (INT) queue -> qu_available; } } /* Determine if there is enough room in the queue for the message. */ if (queue -> qu_available < (size + i)) { /* Queue does not have room for the message. Determine if suspension is required. */ if (suspend) { /* Suspension is requested. */ /* Increment the number of tasks waiting. */ queue -> qu_tasks_waiting++; #ifdef INCLUDE_PROVIEW _RTProf_DumpQueue(RT_PROF_SEND_TO_FRONT_OF_QUEUE,queue,RT_PROF_WAIT); #endif /* Setup the suspend block and suspend the calling task. */ suspend_ptr = &suspend_block; suspend_ptr -> qu_queue = queue; suspend_ptr -> qu_suspend_link.cs_next = NU_NULL; suspend_ptr -> qu_suspend_link.cs_previous = NU_NULL; suspend_ptr -> qu_message_area = (UNSIGNED_PTR) message; suspend_ptr -> qu_message_size = size; task = (TC_TCB *) TCT_Current_Thread(); suspend_ptr -> qu_suspended_task = task; /* Place the task on the urgent message suspension list. */ CSC_Place_On_List((CS_NODE **) &(queue -> qu_urgent_list), &(suspend_ptr -> qu_suspend_link)); /* Move the head pointer of the list to make this suspension the first in the list. */ queue -> qu_urgent_list = (QU_SUSPEND *) (queue -> qu_urgent_list) -> qu_suspend_link.cs_previous; /* Finally, suspend the calling task. Note that the suspension call automatically clears the protection on the queue. */ TCC_Suspend_Task((NU_TASK *) task, NU_QUEUE_SUSPEND, QUC_Cleanup, suspend_ptr, suspend); /* Pickup the return status. */ status = suspend_ptr -> qu_return_status; } else { /* Return a status of NU_QUEUE_FULL because there is no room in the queue for the message. */ status = NU_QUEUE_FULL; #ifdef INCLUDE_PROVIEW _RTProf_DumpQueue(RT_PROF_SEND_TO_FRONT_OF_QUEUE,queue,RT_PROF_FAIL); #endif } } else { /* Determine if a task is waiting on an empty queue. */ if ((queue -> qu_suspension_list) && (queue -> qu_messages == 0)) { /* Task is waiting on queue for a message. */ /* Decrement the number of tasks waiting on queue. */ queue -> qu_tasks_waiting--; #ifdef INCLUDE_PROVIEW _RTProf_DumpQueue(RT_PROF_SEND_TO_FRONT_OF_QUEUE,queue,RT_PROF_OK); #endif /* Remove the first suspended block from the list. */ suspend_ptr = queue -> qu_suspension_list; CSC_Remove_From_List((CS_NODE **) &(queue -> qu_suspension_list), &(suspend_ptr -> qu_suspend_link)); /* Setup the source and destination pointers. */ source = (UNSIGNED_PTR) message; destination = suspend_ptr -> qu_message_area; /* Initialize the return status. */ suspend_ptr -> qu_return_status = NU_SUCCESS; /* Loop to actually copy the message. */ i = (INT) size; do { *(destination++) = *(source); if ((--i) == 0) break; source++; } while (1); /* Return the size of the message copied. */ suspend_ptr -> qu_actual_size = size; /* Wakeup the waiting task and check for preemption. */ preempt = TCC_Resume_Task((NU_TASK *) suspend_ptr -> qu_suspended_task, NU_QUEUE_SUSPEND); /* Determine if preemption needs to take place. */ if (preempt) /* Transfer control to the system if the resumed task function detects a preemption condition. */ TCT_Control_To_System(); } else { /* There is enough room in the queue and no task is waiting. */ /* Setup the source pointer. */ source = (UNSIGNED_PTR) message; destination = queue -> qu_read; /* Process according to the type of message supported. */ if (queue -> qu_fixed_size) { /* Fixed-size message queue. */ /* Determine if the read pointer is at the top of the queue area. */ if (destination == queue -> qu_start) /* Prepare to place the message in the lower part of the queue area. */ destination = queue -> qu_end - size; else /* Backup the length of a message from the current read pointer. */ destination = destination - size; /* Adjust the actual read pointer before the copy is done. */ queue -> qu_read = destination; /* Copy the message into the queue area. */ i = (INT) size; do { *(destination++) = *(source); if ((--i) == 0) break; source++; } while (1); } else { /* Variable-size message queue. */ /* Calculate the number of words remaining at the top of the queue. */ copy_size = destination - queue -> qu_start; /* Determine if part of the message needs to be placed at the bottom of the queue area. */ if (copy_size < (size + i)) /* Compute the starting location for the message. */ destination = queue -> qu_end - ((size +i) - copy_size); else /* Compute the starting location for the message. */ destination = destination - (size + i); /* Adjust the actual queue read pointer also. */ queue -> qu_read = destination; /* Place message size in first location. */ *(destination++) = size; /* Check for a wrap-around condition on the queue. */ if (destination >= queue -> qu_end) /* Wrap the write pointer back to the top of the queue area. */ destination = queue -> qu_start; /* Decrement the number of words remaining by 1 for this extra word of overhead. */ queue -> qu_available--; /* Calculate the number of words remaining from the destination pointer to the bottom of the queue. */ copy_size = queue -> qu_end - destination; /* Determine if the message needs to be wrapped around the edge of the queue area. */ if (copy_size >= size) { /* Copy the whole message at once. */ i = (INT) size; do { *(destination++) = *(source); if ((--i) == 0) break; source++; } while (1); } else { /* Copy the first half of the message. */ i = (INT) copy_size; do { *(destination) = *(source++); if ((--i) == 0) break; destination++; } while (1); /* Copy the second half of the message. */ destination = queue -> qu_start; i = (INT) (size - copy_size); do { *(destination++) = *(source); if ((--i) == 0) break; source++; } while (1); } } /* Decrement the number of available words. */ queue -> qu_available = queue -> qu_available - size; /* Increment the number of messages in the queue. */ queue -> qu_messages++; #ifdef INCLUDE_PROVIEW _RTProf_DumpQueue(RT_PROF_SEND_TO_FRONT_OF_QUEUE,queue,RT_PROF_OK); #endif } } /* Release protection against access to the queue. */ TCT_Unprotect(); /* Return to user mode */ NU_USER_MODE(); /* Return the completion status. */ return(status); } /*************************************************************************/ /* */ /* FUNCTION */ /* */ /* QUS_Broadcast_To_Queue */ /* */ /* DESCRIPTION */ /* */ /* This function sends a message to all tasks waiting for a message */ /* from the specified queue. If there are no tasks waiting for a */ /* message the service performs like a standard send request. */ /* */ /* CALLED BY */ /* */ /* Application */ /* QUSE_Broadcast_To_Queue Error checking shell */ /* */ /* CALLS */ /* */ /* CSC_Place_On_List Place on suspend list */ /* CSC_Priority_Place_On_List Place on priority list */ /* CSC_Remove_From_List Remove from suspend list */ /* [HIC_Make_History_Entry] Make entry in history log */ /* TCC_Resume_Task Resume a suspended task */ /* TCC_Suspend_Task Suspend calling task */ /* TCC_Task_Priority Pickup task's priority */ /* [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 queue */ /* TCT_Unprotect Release protection */ /* */ /* INPUTS */ /* */ /* queue_ptr Queue control block pointer */ /* message Pointer to message to send */ /* size Size of message to send */ /* suspend Suspension option if full */ /* */ /* OUTPUTS */ /* */ /* NU_SUCCESS If service is successful */ /* NU_QUEUE_FULL If queue is currently full */ /* NU_TIMEOUT If timeout on service expires*/ /* NU_QUEUE_DELETED If queue was deleted during */ /* suspension */ /* NU_QUEUE_RESET If queue was reset 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 interfaces to */ /* match those in prototype, */ /* added register options, changed */ /* protection logic to reduce */ /* overhead, optimized copy loop, */ /* resulting in version 1.1 */ /* */ /* 03-18-1994 Verified version 1.1 */ /* */ /*************************************************************************/ STATUS QUS_Broadcast_To_Queue(NU_QUEUE *queue_ptr, VOID *message, UNSIGNED size, UNSIGNED suspend) { R1 QU_QCB *queue; /* Queue control block ptr */ QU_SUSPEND suspend_block; /* Allocate suspension block */ QU_SUSPEND *suspend_ptr; /* Pointer to suspend block */ R3 UNSIGNED_PTR source; /* Pointer to source */ R4 UNSIGNED_PTR destination; /* Pointer to destination */ UNSIGNED copy_size; /* Partial copy size */ R2 INT i; /* Working counter */ TC_TCB *task; /* Task pointer */ STATUS preempt; /* Preempt flag */ STATUS status; /* Completion status */ NU_SUPERV_USER_VARIABLES /* Switch to supervisor mode */ NU_SUPERVISOR_MODE(); /* Move input queue pointer into internal pointer. */ queue = (QU_QCB *) queue_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_QUEUE_ID, (UNSIGNED) queue, (UNSIGNED) message, (UNSIGNED) size); #endif /* Initialize the status as successful. */ status = NU_SUCCESS; /* Protect against simultaneous access to the queue. */ TCT_System_Protect(); /* Determine if an extra word of overhead needs to be added to the calculation. */ if (queue -> qu_fixed_size) /* No overhead. */ i = 0; else { /* Variable messages have one additional word of overhead. */ i = 1; /* Make special check to see if a suspension needs to be forced for a variable length message. */ if ((queue -> qu_suspension_list) && (queue -> qu_messages)) { /* Pickup task control block pointer. */ task = (TC_TCB *) TCT_Current_Thread(); /* Now we know that there are other task(s) are suspended trying to send a variable length message. Determine whether or not a suspension should be forced. */ if ((queue -> qu_fifo_suspend) || (suspend == NU_NO_SUSPEND) || ((queue -> qu_suspension_list) -> qu_suspend_link.cs_priority <= TCC_Task_Priority(task))) /* Bump the computed size to avoid placing the new variable length message ahead of the suspended tasks. */ i = (INT) queue -> qu_available; } } /* Determine if there is enough room in the queue for the message. */ if (queue -> qu_available < (size + i)) { /* Queue does not have room for the message. Determine if suspension is required. */ if (suspend) { /* Suspension is requested. */ /* Increment the number of tasks waiting. */ queue -> qu_tasks_waiting++; #ifdef INCLUDE_PROVIEW _RTProf_DumpQueue(RT_PROF_BROADCAST_TO_QUEUE,queue,RT_PROF_WAIT); #endif /* Setup the suspend block and suspend the calling task. */ suspend_ptr = &suspend_block; suspend_ptr -> qu_queue = queue; suspend_ptr -> qu_suspend_link.cs_next = NU_NULL; suspend_ptr -> qu_suspend_link.cs_previous = NU_NULL; suspend_ptr -> qu_message_area = (UNSIGNED_PTR) message; suspend_ptr -> qu_message_size = size; task = (TC_TCB *) TCT_Current_Thread(); suspend_ptr -> qu_suspended_task = task; /* Determine if priority or FIFO suspension is associated with the queue. */ if (queue -> qu_fifo_suspend) { /* FIFO suspension is required. Link the suspend block into the list of suspended tasks on this queue. */ CSC_Place_On_List((CS_NODE **) &(queue -> qu_suspension_list), &(suspend_ptr -> qu_suspend_link)); } else { /* Get the priority of the current thread so the suspend block can be placed in the appropriate place. */ suspend_ptr -> qu_suspend_link.cs_priority = TCC_Task_Priority(task); CSC_Priority_Place_On_List((CS_NODE **) &(queue -> qu_suspension_list), &(suspend_ptr -> qu_suspend_link)); } /* Finally, suspend the calling task. Note that the suspension call automatically clears the protection on the queue. */ TCC_Suspend_Task((NU_TASK *) task, NU_QUEUE_SUSPEND, QUC_Cleanup, suspend_ptr, suspend); /* Pickup the return status. */ status = suspend_ptr -> qu_return_status; } else { /* Return a status of NU_QUEUE_FULL because there is no room in the queue for the message. */ status = NU_QUEUE_FULL; #ifdef INCLUDE_PROVIEW _RTProf_DumpQueue(RT_PROF_BROADCAST_TO_QUEUE,queue,RT_PROF_FAIL); #endif } } else { /* Determine if a task is waiting on an empty queue. */ if ((queue -> qu_suspension_list) && (queue -> qu_messages == 0)) { #ifdef INCLUDE_PROVIEW _RTProf_DumpQueue(RT_PROF_BROADCAST_TO_QUEUE,queue,RT_PROF_OK); #endif /* Yes, one or more tasks are waiting for a message from this queue. */ preempt = 0; do { /* Decrement the number of tasks waiting on queue. */ queue -> qu_tasks_waiting--; /* Remove the first suspended block from the list. */ suspend_ptr = queue -> qu_suspension_list; CSC_Remove_From_List((CS_NODE **) &(queue -> qu_suspension_list), &(suspend_ptr -> qu_suspend_link)); /* Setup the source and destination pointers. */ source = (UNSIGNED_PTR) message; destination = suspend_ptr -> qu_message_area; /* Initialize the return status. */ suspend_ptr -> qu_return_status = NU_SUCCESS; /* Loop to actually copy the message. */ i = (INT) size; do { *(destination++) = *(source); if ((--i) == 0) break; source++; } while (1); /* Return the size of the message copied. */ suspend_ptr -> qu_actual_size = size; /* Wakeup the waiting task and check for preemption. */ preempt = preempt | TCC_Resume_Task((NU_TASK *) suspend_ptr -> qu_suspended_task, NU_QUEUE_SUSPEND); /* Move the suspend pointer to the next node, which is now at the head of the list. */ suspend_ptr = queue -> qu_suspension_list; } while (suspend_ptr); /* Determine if preemption needs to take place. */ if (preempt) /* Transfer control to the system if the resumed task function detects a preemption condition. */ TCT_Control_To_System(); } else { /* There is enough room in the queue and no task is waiting. */ /* Setup the source pointer. */ source = (UNSIGNED_PTR) message; destination = queue -> qu_write; /* Process according to the type of message supported. */ if (queue -> qu_fixed_size) { /* Fixed-size messages are supported by this queue. */ /* Loop to copy the message into the queue area. */ i = (INT) size; do { *(destination++) = *(source); if ((--i) == 0) break; source++; } while (1); } else { /* Variable-size messages are supported. Processing must check for queue wrap-around conditions. */ /* Place message size in first location. */ *(destination++) = size; /* Check for a wrap-around condition on the queue. */ if (destination >= queue -> qu_end) /* Wrap the write pointer back to the top of the queue area. */ destination = queue -> qu_start; /* Decrement the number of words remaining by 1 for this extra word of overhead. */ queue -> qu_available--; /* Calculate the number of words remaining from the write pointer to the bottom of the queue. */ copy_size = queue -> qu_end - destination; /* Determine if the message needs to be wrapped around the edge of the queue area. */ if (copy_size >= size) { /* Copy the whole message at once. */ i = (INT) size; do { *(destination++) = *(source); if ((--i) == 0) break; source++; } while(1); } else { /* Copy the first half of the message. */ i = (INT) copy_size; do { *(destination) = *(source++); if ((--i) == 0) break; destination++; } while (1); /* Copy the second half of the message. */ destination = queue -> qu_start; i = (INT) (size - copy_size); do { *(destination++) = *(source); if ((--i) == 0) break; source++; } while (1); } } /* Check again for wrap-around condition on the write pointer. */ if (destination >= queue -> qu_end) /* Move the write pointer to the top of the queue area. */ queue -> qu_write = queue -> qu_start; else /* Simply copy the last position of the destination pointer into the write pointer. */ queue -> qu_write = destination; /* Decrement the number of available words. */ queue -> qu_available = queue -> qu_available - size; /* Increment the number of messages in the queue. */ queue -> qu_messages++; #ifdef INCLUDE_PROVIEW _RTProf_DumpQueue(RT_PROF_BROADCAST_TO_QUEUE,queue,RT_PROF_OK); #endif } } /* Release protection against access to the queue. */ TCT_Unprotect(); /* Return to user mode */ NU_USER_MODE(); /* Return the completion status. */ return(status); }