📄 os_q.lst
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C51 COMPILER V7.10 OS_Q 05/10/2005 00:01:49 PAGE 1
C51 COMPILER V7.10, COMPILATION OF MODULE OS_Q
OBJECT MODULE PLACED IN OS_Q.OBJ
COMPILER INVOKED BY: D:\Keil\C51\BIN\C51.EXE OS_Q.C LARGE OPTIMIZE(6,SIZE) BROWSE NOINTPROMOTE DEBUG OBJECTEXTEND
line level source
1 /*
2 *********************************************************************************************************
3 * uC/OS-II
4 * The Real-Time Kernel
5 * MESSAGE QUEUE MANAGEMENT
6 *
7 * (c) Copyright 1992-1998, Jean J. Labrosse, Plantation, FL
8 * All Rights Reserved
9 *
10 * V2.00
11 *
12 * File : OS_Q.C
13 * By : Jean J. Labrosse
14 *********************************************************************************************************
15 */
16
17 #ifndef OS_MASTER_FILE
18 #include "includes.h"
19 #endif
20
21 #if OS_Q_EN && (OS_MAX_QS >= 2)
/*
*********************************************************************************************************
* LOCAL DATA TYPES
*********************************************************************************************************
*/
typedef struct os_q { /* QUEUE CONTROL BLOCK */
struct os_q *OSQPtr; /* Link to next queue control block in list of free blocks */
void **OSQStart; /* Pointer to start of queue data */
void **OSQEnd; /* Pointer to end of queue data */
void **OSQIn; /* Pointer to where next message will be inserted in the Q */
void **OSQOut; /* Pointer to where next message will be extracted from the Q */
INT16U OSQSize; /* Size of queue (maximum number of entries) */
INT16U OSQEntries; /* Current number of entries in the queue */
} OS_Q;
/*
*********************************************************************************************************
* LOCAL GLOBAL VARIABLES
*********************************************************************************************************
*/
static OS_Q *OSQFreeList; /* Pointer to list of free QUEUE control blocks */
static OS_Q OSQTbl[OS_MAX_QS]; /* Table of QUEUE control blocks */
/*$PAGE*/
/*
*********************************************************************************************************
* ACCEPT MESSAGE FROM QUEUE
*
* Description: This function checks the queue to see if a message is available. Unlike OSQPend(),
* OSQAccept() does not suspend the calling task if a message is not available.
*
* Arguments : pevent is a pointer to the event control block
C51 COMPILER V7.10 OS_Q 05/10/2005 00:01:49 PAGE 2
*
* Returns : != (void *)0 is the message in the queue if one is available. The message is removed
* from the so the next time OSQAccept() is called, the queue will contain
* one less entry.
* == (void *)0 if the queue is empty
* if you passed an invalid event type
*********************************************************************************************************
*/
#if OS_Q_Accept_EN
void *OSQAccept (OS_EVENT *pevent)reentrant
{
void *msg;
OS_Q *pq;
OS_ENTER_CRITICAL();
if (pevent->OSEventType != OS_EVENT_TYPE_Q) { /* Validate event block type */
OS_EXIT_CRITICAL();
return ((void *)0);
}
pq = pevent->OSEventPtr; /* Point at queue control block */
if (pq->OSQEntries != 0) { /* See if any messages in the queue */
msg = *pq->OSQOut++; /* Yes, extract oldest message from the queue */
pq->OSQEntries--; /* Update the number of entries in the queue */
if (pq->OSQOut == pq->OSQEnd) { /* Wrap OUT pointer if we are at the end of the queue */
pq->OSQOut = pq->OSQStart;
}
} else {
msg = (void *)0; /* Queue is empty */
}
OS_EXIT_CRITICAL();
return (msg); /* Return message received (or NULL) */
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* CREATE A MESSAGE QUEUE
*
* Description: This function creates a message queue if free event control blocks are available.
*
* Arguments : start is a pointer to the base address of the message queue storage area. The
* storage area MUST be declared as an array of pointers to 'void' as follows
*
* void *MessageStorage[size]
*
* size is the number of elements in the storage area
*
* Returns : != (void *)0 is a pointer to the event control clock (OS_EVENT) associated with the
* created queue
* == (void *)0 if no event control blocks were available
*********************************************************************************************************
*/
#if OS_Q_Create_EN
OS_EVENT *OSQCreate (void **start, INT16U size)reentrant
{
OS_EVENT *pevent;
OS_Q *pq;
OS_ENTER_CRITICAL();
pevent = OSEventFreeList; /* Get next free event control block */
C51 COMPILER V7.10 OS_Q 05/10/2005 00:01:49 PAGE 3
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) { /* See if we have an event control block */
OS_ENTER_CRITICAL(); /* Get a free queue control block */
pq = OSQFreeList;
if (OSQFreeList != (OS_Q *)0) {
OSQFreeList = OSQFreeList->OSQPtr;
}
OS_EXIT_CRITICAL();
if (pq != (OS_Q *)0) { /* See if we were able to get a queue control block */
pq->OSQStart = start; /* Yes, initialize the queue */
pq->OSQEnd = &start[size];
pq->OSQIn = start;
pq->OSQOut = start;
pq->OSQSize = size;
pq->OSQEntries = 0;
pevent->OSEventType = OS_EVENT_TYPE_Q;
pevent->OSEventPtr = pq;
OSEventWaitListInit(pevent);
} else { /* No, since we couldn't get a queue control block */
OS_ENTER_CRITICAL(); /* Return event control block on error */
pevent->OSEventPtr = (void *)OSEventFreeList;
OSEventFreeList = pevent;
OS_EXIT_CRITICAL();
pevent = (OS_EVENT *)0;
}
}
return (pevent);
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* FLUSH QUEUE
*
* Description : This function is used to flush the contents of the message queue.
*
* Arguments : none
*
* Returns : OS_NO_ERR upon success
* OS_ERR_EVENT_TYPE If you didn't pass a pointer to a queue
*********************************************************************************************************
*/
#if OS_Q_Flush_EN
INT8U OSQFlush (OS_EVENT *pevent)reentrant
{
OS_Q *pq;
OS_ENTER_CRITICAL();
if (pevent->OSEventType != OS_EVENT_TYPE_Q) { /* Validate event block type */
OS_EXIT_CRITICAL();
return (OS_ERR_EVENT_TYPE);
}
pq = pevent->OSEventPtr; /* Point to queue storage structure */
pq->OSQIn = pq->OSQStart;
pq->OSQOut = pq->OSQStart;
pq->OSQEntries = 0;
OS_EXIT_CRITICAL();
return (OS_NO_ERR);
C51 COMPILER V7.10 OS_Q 05/10/2005 00:01:49 PAGE 4
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* QUEUE MODULE INITIALIZATION
*
* Description : This function is called by uC/OS-II to initialize the message queue module. Your
* application MUST NOT call this function.
*
* Arguments : none
*
* Returns : none
*********************************************************************************************************
*/
void OSQInit (void)reentrant
{
INT16U i;
for (i = 0; i < (OS_MAX_QS - 1); i++) { /* Init. list of free QUEUE control blocks */
OSQTbl[i].OSQPtr = &OSQTbl[i+1];
}
OSQTbl[OS_MAX_QS - 1].OSQPtr = (OS_Q *)0;
OSQFreeList = &OSQTbl[0];
}
/*$PAGE*/
/*
*********************************************************************************************************
* PEND ON A QUEUE FOR A MESSAGE
*
* Description: This function waits for a message to be sent to a queue
*
* Arguments : pevent is a pointer to the event control block associated with the desired queue
*
* timeout is an optional timeout period (in clock ticks). If non-zero, your task will
* wait for a message to arrive at the queue up to the amount of time
* specified by this argument. If you specify 0, however, your task will wait
* forever at the specified queue or, until a message arrives.
*
* err is a pointer to where an error message will be deposited. Possible error
* messages are:
*
* OS_NO_ERR The call was successful and your task received a message.
* OS_TIMEOUT A message was not received within the specified timeout
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