📄 os_mbox.lst
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C51 COMPILER V7.02b OS_MBOX 11/29/2006 14:48:13 PAGE 1
C51 COMPILER V7.02b, COMPILATION OF MODULE OS_MBOX
OBJECT MODULE PLACED IN .\obj\OS_MBOX.obj
COMPILER INVOKED BY: C:\Keil\C51\BIN\C51.EXE uCosii\OS_MBOX.C LARGE BROWSE DEBUG OBJECTEXTEND PRINT(.\lst\OS_MBOX.lst) O
-BJECT(.\obj\OS_MBOX.obj)
stmt level source
1 /*
2 *********************************************************************************************************
3 * uC/OS-II
4 * The Real-Time Kernel
5 * MESSAGE MAILBOX MANAGEMENT
6 *
7 * (c) Copyright 1992-2001, Jean J. Labrosse, Weston, FL
8 * All Rights Reserved
9 *
10 * File : OS_MBOX.C
11 * By : Jean J. Labrosse
12 *********************************************************************************************************
13 */
14
15 #ifndef OS_MASTER_FILE
16 #include "source\includes.h"
17 #endif
18
19 #if OS_MBOX_EN > 0
/*
*********************************************************************************************************
* ACCEPT MESSAGE FROM MAILBOX
*
* Description: This function checks the mailbox to see if a message is available. Unlike OSMboxPend(),
* OSMboxAccept() does not suspend the calling task if a message is not available.
*
* Arguments : pevent is a pointer to the event control block
*
* Returns : != (void *)0 is the message in the mailbox if one is available. The mailbox is cleared
* so the next time OSMboxAccept() is called, the mailbox will be empty.
* == (void *)0 if the mailbox is empty or,
* if 'pevent' is a NULL pointer or,
* if you didn't pass the proper event pointer.
*********************************************************************************************************
*/
#if OS_MBOX_ACCEPT_EN > 0
void *OSMboxAccept (OS_EVENT *pevent) reentrant
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
void *msg;
#if OS_ARG_CHK_EN > 0
if (pevent == (OS_EVENT *)0) { /* Validate 'pevent' */
return ((void *)0);
}
if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) { /* Validate event block type */
return ((void *)0);
}
#endif
OS_ENTER_CRITICAL();
C51 COMPILER V7.02b OS_MBOX 11/29/2006 14:48:13 PAGE 2
msg = pevent->OSEventPtr;
pevent->OSEventPtr = (void *)0; /* Clear the mailbox */
OS_EXIT_CRITICAL();
return (msg); /* Return the message received (or NULL) */
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* CREATE A MESSAGE MAILBOX
*
* Description: This function creates a message mailbox if free event control blocks are available.
*
* Arguments : msg is a pointer to a message that you wish to deposit in the mailbox. If
* you set this value to the NULL pointer (i.e. (void *)0) then the mailbox
* will be considered empty.
*
* Returns : != (OS_EVENT *)0 is a pointer to the event control clock (OS_EVENT) associated with the
* created mailbox
* == (OS_EVENT *)0 if no event control blocks were available
*********************************************************************************************************
*/
OS_EVENT *OSMboxCreate (void *msg) reentrant
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
OS_EVENT *pevent;
if (OSIntNesting > 0) { /* See if called from ISR ... */
return ((OS_EVENT *)0); /* ... can't CREATE from an ISR */
}
OS_ENTER_CRITICAL();
pevent = OSEventFreeList; /* Get next free event control block */
if (OSEventFreeList != (OS_EVENT *)0) { /* See if pool of free ECB pool was empty */
OSEventFreeList = (OS_EVENT *)OSEventFreeList->OSEventPtr;
}
OS_EXIT_CRITICAL();
if (pevent != (OS_EVENT *)0) {
pevent->OSEventType = OS_EVENT_TYPE_MBOX;
pevent->OSEventPtr = msg; /* Deposit message in event control block */
OS_EventWaitListInit(pevent);
}
return (pevent); /* Return pointer to event control block */
}
/*$PAGE*/
/*
*********************************************************************************************************
* DELETE A MAIBOX
*
* Description: This function deletes a mailbox and readies all tasks pending on the mailbox.
*
* Arguments : pevent is a pointer to the event control block associated with the desired
* mailbox.
*
* opt determines delete options as follows:
* opt == OS_DEL_NO_PEND Delete the mailbox ONLY if no task pending
* opt == OS_DEL_ALWAYS Deletes the mailbox even if tasks are waiting.
* In this case, all the tasks pending will be readied.
*
C51 COMPILER V7.02b OS_MBOX 11/29/2006 14:48:13 PAGE 3
* err is a pointer to an error code that can contain one of the following values:
* OS_NO_ERR The call was successful and the mailbox was deleted
* OS_ERR_DEL_ISR If you attempted to delete the mailbox from an ISR
* OS_ERR_INVALID_OPT An invalid option was specified
* OS_ERR_TASK_WAITING One or more tasks were waiting on the mailbox
* OS_ERR_EVENT_TYPE If you didn't pass a pointer to a mailbox
* OS_ERR_PEVENT_NULL If 'pevent' is a NULL pointer.
*
* Returns : pevent upon error
* (OS_EVENT *)0 if the mailbox was successfully deleted.
*
* Note(s) : 1) This function must be used with care. Tasks that would normally expect the presence of
* the mailbox MUST check the return code of OSMboxPend().
* 2) OSMboxAccept() callers will not know that the intended mailbox has been deleted unless
* they check 'pevent' to see that it's a NULL pointer.
* 3) This call can potentially disable interrupts for a long time. The interrupt disable
* time is directly proportional to the number of tasks waiting on the mailbox.
* 4) Because ALL tasks pending on the mailbox will be readied, you MUST be careful in
* applications where the mailbox is used for mutual exclusion because the resource(s)
* will no longer be guarded by the mailbox.
*********************************************************************************************************
*/
#if OS_MBOX_DEL_EN > 0
OS_EVENT *OSMboxDel (OS_EVENT *pevent, INT8U opt, INT8U *err) reentrant
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
BOOLEAN tasks_waiting;
if (OSIntNesting > 0) { /* See if called from ISR ... */
*err = OS_ERR_DEL_ISR; /* ... can't DELETE from an ISR */
return (pevent);
}
#if OS_ARG_CHK_EN > 0
if (pevent == (OS_EVENT *)0) { /* Validate 'pevent' */
*err = OS_ERR_PEVENT_NULL;
return (pevent);
}
if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) { /* Validate event block type */
*err = OS_ERR_EVENT_TYPE;
return (pevent);
}
#endif
OS_ENTER_CRITICAL();
if (pevent->OSEventGrp != 0x00) { /* See if any tasks waiting on mailbox */
tasks_waiting = TRUE; /* Yes */
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