FreeCalypso > hg > fc-tourmaline
diff src/nucleus/mbc.c @ 0:4e78acac3d88
src/{condat,cs,gpf,nucleus}: import from Selenite
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Fri, 16 Oct 2020 06:23:26 +0000 |
| parents | |
| children |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/nucleus/mbc.c Fri Oct 16 06:23:26 2020 +0000 @@ -0,0 +1,992 @@ +/*************************************************************************/ +/* */ +/* 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(); +} + + + + + + +