FreeCalypso > hg > fc-tourmaline
view src/nucleus/mbc.c @ 184:73fd75652066
rm src/ui/mfw/mfw_bt* and src/ui/mfw/mfw_fm.[ch]
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Tue, 19 Jan 2021 05:35:14 +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 */ /* */ /* mbc.c Nucleus PLUS 1.14 */ /* */ /* COMPONENT */ /* */ /* MB - Mailbox Management */ /* */ /* DESCRIPTION */ /* */ /* This file contains the core routines for the Mailbox management */ /* component. */ /* */ /* DATA STRUCTURES */ /* */ /* None */ /* */ /* FUNCTIONS */ /* */ /* MBC_Create_Mailbox Create a mailbox */ /* MBC_Delete_Mailbox Delete a mailbox */ /* MBC_Send_To_Mailbox Send a mailbox message */ /* MBC_Receive_From_Mailbox Receive a mailbox message */ /* MBC_Cleanup Cleanup on timeout or a */ /* terminate condition */ /* */ /* DEPENDENCIES */ /* */ /* cs_extr.h Common Service functions */ /* tc_extr.h Thread Control functions */ /* mb_extr.h Mailbox functions */ /* hi_extr.h History functions */ /* */ /* HISTORY */ /* */ /* DATE REMARKS */ /* */ /* 03-01-1993 Created initial version 1.0 */ /* 04-19-1993 Verified version 1.0 */ /* 08-09-1993 Corrected pointer retrieval */ /* loop, resulting in version 1.0a */ /* 08-09-1993 Verified version 1.0a */ /* 03-01-1994 Moved non-core functions into */ /* supplemental files, changed */ /* function interfaces to match */ /* those in prototype, added */ /* register options, changed */ /* protection logic to reduce */ /* overhead, resulting in */ /* version 1.1 */ /* */ /* 03-18-1994 Verified version 1.1 */ /* 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 "mb_extr.h" /* Mailbox functions */ #include "hi_extr.h" /* History functions */ #include "profiler.h" /* ProView interface */ /* Define external inner-component global data references. */ extern CS_NODE *MBD_Created_Mailboxes_List; extern UNSIGNED MBD_Total_Mailboxes; extern TC_PROTECT MBD_List_Protect; /* Define internal component function prototypes. */ VOID MBC_Cleanup(VOID *information); /*************************************************************************/ /* */ /* FUNCTION */ /* */ /* MBC_Create_Mailbox */ /* */ /* DESCRIPTION */ /* */ /* This function creates a mailbox and then places it on the list */ /* of created mailboxes. */ /* */ /* CALLED BY */ /* */ /* Application */ /* MBCE_Create_Mailbox Error checking shell */ /* */ /* CALLS */ /* */ /* CSC_Place_On_List Add node to linked-list */ /* [HIC_Make_History_Entry] Make entry in history log */ /* [TCT_Check_Stack] Stack checking function */ /* TCT_Protect Data structure protect */ /* TCT_Unprotect Un-protect data structure */ /* */ /* INPUTS */ /* */ /* mailbox_ptr Mailbox control block pointer*/ /* name Mailbox name */ /* suspend_type Suspension type */ /* */ /* 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 interface to */ /* match the prototype, added */ /* register variable logic, */ /* resulting in version 1.1 */ /* */ /* 03-18-1994 Verified version 1.1 */ /* */ /*************************************************************************/ STATUS MBC_Create_Mailbox(NU_MAILBOX *mailbox_ptr, CHAR *name, OPTION suspend_type) { R1 MB_MCB *mailbox; /* Mailbox control block ptr */ INT i; /* Working index variable */ NU_SUPERV_USER_VARIABLES /* Switch to supervisor mode */ NU_SUPERVISOR_MODE(); /* 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_CREATE_MAILBOX_ID, (UNSIGNED) mailbox, (UNSIGNED) name, (UNSIGNED) suspend_type); #endif /* First, clear the mailbox ID just in case it is an old Mailbox Control Block. */ mailbox -> mb_id = 0; /* Fill in the mailbox name. */ for (i = 0; i < NU_MAX_NAME; i++) mailbox -> mb_name[i] = name[i]; /* Clear the message present flag- initial it to "no message present." */ mailbox -> mb_message_present = NU_FALSE; /* Setup the mailbox suspension type. */ if (suspend_type == NU_FIFO) /* FIFO suspension is selected, setup the flag accordingly. */ mailbox -> mb_fifo_suspend = NU_TRUE; else /* Priority suspension is selected. */ mailbox -> mb_fifo_suspend = NU_FALSE; /* Clear the suspension list pointer. */ mailbox -> mb_suspension_list = NU_NULL; /* Clear the number of tasks waiting on the mailbox counter. */ mailbox -> mb_tasks_waiting = 0; /* Initialize link pointers. */ mailbox -> mb_created.cs_previous = NU_NULL; mailbox -> mb_created.cs_next = NU_NULL; /* Protect against access to the list of created mailboxes. */ TCT_Protect(&MBD_List_Protect); /* At this point the mailbox is completely built. The ID can now be set and it can be linked into the created mailbox list. */ mailbox -> mb_id = MB_MAILBOX_ID; /* Link the mailbox into the list of created mailboxes and increment the total number of mailboxes in the system. */ CSC_Place_On_List(&MBD_Created_Mailboxes_List, &(mailbox -> mb_created)); MBD_Total_Mailboxes++; #ifdef INCLUDE_PROVIEW _RTProf_DumpMailBox(RT_PROF_CREATE_MAILBOX,mailbox,RT_PROF_OK); #endif /* INCLUDE_PROVIEW */ /* Release protection against access to the list of created mailboxes. */ TCT_Unprotect(); /* Return to user mode */ NU_USER_MODE(); /* Return successful completion. */ return(NU_SUCCESS); } /*************************************************************************/ /* */ /* FUNCTION */ /* */ /* MBC_Delete_Mailbox */ /* */ /* DESCRIPTION */ /* */ /* This function deletes a mailbox and removes it from the list of */ /* created mailboxes. All tasks suspended on the mailbox are */ /* resumed. Note that this function does not free the memory */ /* associated with the mailbox control block. */ /* */ /* CALLED BY */ /* */ /* Application */ /* MBCE_Delete_Mailbox Error checking shell */ /* */ /* CALLS */ /* */ /* CSC_Remove_From_List Remove node from list */ /* [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_Protect Protect created list */ /* TCT_Set_Current_Protect Setup current protection ptr */ /* TCT_System_Protect Protect against system access*/ /* TCT_System_Unprotect Release system protection */ /* TCT_Unprotect Release protection */ /* */ /* INPUTS */ /* */ /* mailbox_ptr Mailbox 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 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 MBC_Delete_Mailbox(NU_MAILBOX *mailbox_ptr) { R1 MB_MCB *mailbox; /* Mailbox control block ptr */ MB_SUSPEND *suspend_ptr; /* Suspend block pointer */ MB_SUSPEND *next_ptr; /* Next suspend block pointer*/ STATUS preempt; /* Status for resume call */ NU_SUPERV_USER_VARIABLES /* Switch to supervisor mode */ NU_SUPERVISOR_MODE(); /* 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_DELETE_MAILBOX_ID, (UNSIGNED) mailbox, (UNSIGNED) 0, (UNSIGNED) 0); #endif /* Call protection just in case another thread is using the mailbox. */ TCT_System_Protect(); #ifdef INCLUDE_PROVIEW _RTProf_DumpMailBox(RT_PROF_DELETE_MAILBOX,mailbox,RT_PROF_OK); #endif /* INCLUDE_PROVIEW */ /* Clear the mailbox ID. */ mailbox -> mb_id = 0; /* Clear protection. */ TCT_Unprotect(); /* Protect against access to the list of created mailboxes. */ TCT_Protect(&MBD_List_Protect); /* Remove the mailbox from the list of created mailboxes. */ CSC_Remove_From_List(&MBD_Created_Mailboxes_List, &(mailbox -> mb_created)); /* Decrement the total number of created mailboxes. */ MBD_Total_Mailboxes--; /* Pickup the suspended task pointer list. */ suspend_ptr = mailbox -> mb_suspension_list; /* Walk the chain task(s) currently suspended on the mailbox. */ preempt = 0; while (suspend_ptr) { /* Protect against system access. */ TCT_System_Protect(); /* Resume the suspended task. Insure that the status returned is NU_MAILBOX_DELETED. */ suspend_ptr -> mb_return_status = NU_MAILBOX_DELETED; /* Point to the next suspend structure in the link. */ next_ptr = (MB_SUSPEND *) (suspend_ptr -> mb_suspend_link.cs_next); /* Resume the specified task. */ preempt = preempt | TCC_Resume_Task((NU_TASK *) suspend_ptr -> mb_suspended_task, NU_MAILBOX_SUSPEND); /* Determine if the next is the same as the head pointer. */ if (next_ptr == mailbox -> mb_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; /* Setup current protection pointer. */ TCT_Set_Current_Protect(&MBD_List_Protect); /* Unprotect the system protection. */ TCT_System_Unprotect(); } /* 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 list of created mailboxes. */ TCT_Unprotect(); /* Return to user mode */ NU_USER_MODE(); /* Return a successful completion. */ return(NU_SUCCESS); } /*************************************************************************/ /* */ /* FUNCTION */ /* */ /* MBC_Send_To_Mailbox */ /* */ /* DESCRIPTION */ /* */ /* This function sends a 4-word message to the specified mailbox. */ /* If there are one or more tasks suspended on the mailbox for a */ /* message, the message is copied into the message area of the */ /* first task waiting and that task is resumed. If the mailbox */ /* is full, suspension of the calling task is possible. */ /* */ /* CALLED BY */ /* */ /* Application */ /* MBCE_Send_To_Mailbox 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 against system access*/ /* 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 MBC_Send_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 */ R3 UNSIGNED *source_ptr; /* Pointer to source */ R4 UNSIGNED *destination_ptr; /* Pointer to destination */ 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 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_SEND_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 waiting. */ mailbox -> mb_tasks_waiting++; #ifdef INCLUDE_PROVIEW _RTProf_DumpMailBox(RT_PROF_SEND_TO_MAILBOX,mailbox,RT_PROF_WAIT); #endif /* INCLUDE_PROVIEW */ /* 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_SEND_TO_MAILBOX,mailbox,RT_PROF_FAIL); #endif /* INCLUDE_PROVIEW */ } } else { /* Determine if a task is waiting on the mailbox. */ if (mailbox -> mb_suspension_list) { /* Task is waiting on mailbox for a message. */ /* Decrement the number of tasks waiting on mailbox. */ mailbox -> mb_tasks_waiting--; #ifdef INCLUDE_PROVIEW _RTProf_DumpMailBox(RT_PROF_SEND_TO_MAILBOX,mailbox,RT_PROF_OK); #endif /* INCLUDE_PROVIEW */ /* Remove the first suspended block from the list. */ suspend_ptr = mailbox -> mb_suspension_list; CSC_Remove_From_List((CS_NODE **) &(mailbox -> mb_suspension_list), &(suspend_ptr -> mb_suspend_link)); /* 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; /* Wakeup the waiting task and check for preemption. */ preempt = TCC_Resume_Task((NU_TASK *) suspend_ptr -> mb_suspended_task, NU_MAILBOX_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 { /* 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_SEND_TO_MAILBOX,mailbox,RT_PROF_OK); #endif /* INCLUDE_PROVIEW */ } } /* Release protection. */ TCT_Unprotect(); /* Return to user mode */ NU_USER_MODE(); /* Return the completion status. */ return(status); } /*************************************************************************/ /* */ /* FUNCTION */ /* */ /* MBC_Receive_From_Mailbox */ /* */ /* DESCRIPTION */ /* */ /* This function receives a message from the specified mailbox. */ /* If there is a message currently in the mailbox, the message is */ /* removed from the mailbox and placed in the caller's area. */ /* Otherwise, if no message is present in the mailbox, suspension */ /* of the calling task is possible. */ /* */ /* CALLED BY */ /* */ /* Application */ /* MBCE_Receive_From_Mailbox 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 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 mailbox */ /* TCT_Unprotect Release protection */ /* */ /* INPUTS */ /* */ /* mailbox_ptr Mailbox control block pointer*/ /* message Pointer to message to send */ /* suspend Suspension option if empty */ /* */ /* OUTPUTS */ /* */ /* NU_SUCCESS If service is successful */ /* NU_MAILBOX_EMPTY If mailbox is currently empty*/ /* 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 MBC_Receive_From_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 */ R3 UNSIGNED *source_ptr; /* Pointer to source */ R4 UNSIGNED *destination_ptr; /* Pointer to destination */ TC_TCB *task; /* Task pointer */ STATUS preempt; /* Preemption flag */ STATUS status; /* Completion status */ NU_SUPERV_USER_VARIABLES /* Switch to supervisor mode */ NU_SUPERVISOR_MODE(); /* 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_RECEIVE_FROM_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) { /* Copy message from mailbox into the caller's area. */ /* Setup the source and destination pointers. */ source_ptr = &(mailbox -> mb_message_area[0]); destination_ptr = (UNSIGNED *) message; /* 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); /* Determine if another task is waiting to place something into the mailbox. */ if (mailbox -> mb_suspension_list) { /* Yes, another task is waiting to send something to the mailbox. */ /* Decrement the number of tasks waiting counter. */ mailbox -> mb_tasks_waiting--; #ifdef INCLUDE_PROVIEW _RTProf_DumpMailBox(RT_PROF_RECEIVE_FROM_MAILBOX,mailbox,RT_PROF_OK); #endif /* INCLUDE_PROVIEW */ /* Remove the first suspended block from the list. */ suspend_ptr = mailbox -> mb_suspension_list; CSC_Remove_From_List((CS_NODE **) &(mailbox -> mb_suspension_list), &(suspend_ptr -> mb_suspend_link)); /* Setup the source and destination pointers. */ source_ptr = suspend_ptr -> mb_message_area; destination_ptr = &(mailbox -> mb_message_area[0]); /* 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; /* Resume the suspended task. */ preempt = TCC_Resume_Task((NU_TASK *) suspend_ptr -> mb_suspended_task, NU_MAILBOX_SUSPEND); /* 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 { /* Clear the message present flag. */ mailbox -> mb_message_present = NU_FALSE; #ifdef INCLUDE_PROVIEW _RTProf_DumpMailBox(RT_PROF_RECEIVE_FROM_MAILBOX,mailbox,RT_PROF_OK); #endif /* INCLUDE_PROVIEW */ } } else { /* Mailbox is empty. Determine if suspension is required. */ if (suspend) { /* Suspension is required. */ /* Increment the number of tasks waiting on the mailbox counter. */ mailbox -> mb_tasks_waiting++; #ifdef INCLUDE_PROVIEW _RTProf_DumpMailBox(RT_PROF_RECEIVE_FROM_MAILBOX,mailbox,RT_PROF_WAIT); #endif /* INCLUDE_PROVIEW */ /* 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_block.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_block, suspend); /* Pickup the return status. */ status = suspend_ptr -> mb_return_status; } else { /* Return a status of NU_MAILBOX_EMPTY because there is nothing in the mailbox. */ status = NU_MAILBOX_EMPTY; #ifdef INCLUDE_PROVIEW _RTProf_DumpMailBox(RT_PROF_RECEIVE_FROM_MAILBOX,mailbox,RT_PROF_FAIL); #endif /* INCLUDE_PROVIEW */ } } /* Release protection. */ TCT_Unprotect(); /* Return to user mode */ NU_USER_MODE(); /* Return the completion status. */ return(status); } /*************************************************************************/ /* */ /* FUNCTION */ /* */ /* MBC_Cleanup */ /* */ /* DESCRIPTION */ /* */ /* This function is responsible for removing a suspension block */ /* from a mailbox. It is not called unless a timeout or a task */ /* terminate is in progress. Note that protection is already in */ /* effect - the same protection at suspension time. */ /* */ /* CALLED BY */ /* */ /* TCC_Timeout Task timeout */ /* TCC_Terminate Task terminate */ /* */ /* CALLS */ /* */ /* CSC_Remove_From_List Remove suspend block from */ /* the suspension list */ /* */ /* INPUTS */ /* */ /* information Pointer to suspend block */ /* */ /* OUTPUTS */ /* */ /* None */ /* */ /* HISTORY */ /* */ /* DATE REMARKS */ /* */ /* 03-01-1993 Created initial version 1.0 */ /* 04-19-1993 Verified version 1.0 */ /* */ /*************************************************************************/ VOID MBC_Cleanup(VOID *information) { MB_SUSPEND *suspend_ptr; /* Suspension block pointer */ NU_SUPERV_USER_VARIABLES /* Switch to supervisor mode */ NU_SUPERVISOR_MODE(); /* Use the information pointer as a suspend pointer. */ suspend_ptr = (MB_SUSPEND *) information; /* By default, indicate that the service timed-out. It really does not matter if this function is called from a terminate request since the task does not resume. */ suspend_ptr -> mb_return_status = NU_TIMEOUT; /* Decrement the number of tasks waiting counter. */ (suspend_ptr -> mb_mailbox) -> mb_tasks_waiting--; /* Unlink the suspend block from the suspension list. */ CSC_Remove_From_List((CS_NODE **) &((suspend_ptr -> mb_mailbox) -> mb_suspension_list), &(suspend_ptr -> mb_suspend_link)); /* Return to user mode */ NU_USER_MODE(); }