?? os_q.lst
字號:
C51 COMPILER V8.02 OS_Q 05/22/2008 18:01:52 PAGE 1
C51 COMPILER V8.02, COMPILATION OF MODULE OS_Q
OBJECT MODULE PLACED IN OS_Q.obj
COMPILER INVOKED BY: C:\Keil\C51\BIN\C51.EXE ucos\OS_Q.C LARGE BROWSE INCDIR(.\dataflash;.\lcd;.\task;.\uart;.\ucos;.\ke
-y) DEBUG OBJECTEXTEND PRINT(.\OS_Q.lst) OBJECT(OS_Q.obj)
line level source
1 /*
2 *********************************************************************************************************
3 * uC/OS-II
4 * The Real-Time Kernel
5 * MESSAGE QUEUE MANAGEMENT
6 *
7 * (c) Copyright 1992-2002, Jean J. Labrosse, Weston, FL
8 * All Rights Reserved
9 *
10 * File : OS_Q.C
11 * By : Jean J. Labrosse
12 *********************************************************************************************************
13 */
14
15 #ifndef OS_MASTER_FILE
16 #include "includes.h"
17 #endif
18
19 #if (OS_Q_EN > 0) && (OS_MAX_QS > 0)
20 /*
21 *********************************************************************************************************
22 * ACCEPT MESSAGE FROM QUEUE
23 *
24 * Description: This function checks the queue to see if a message is available. Unlike OSQPend(),
25 * OSQAccept() does not suspend the calling task if a message is not available.
26 *
27 * Arguments : pevent is a pointer to the event control block
28 *
29 * Returns : != (void *)0 is the message in the queue if one is available. The message is removed
30 * from the so the next time OSQAccept() is called, the queue will contain
31 * one less entry.
32 * == (void *)0 if the queue is empty or,
33 * if 'pevent' is a NULL pointer or,
34 * if you passed an invalid event type
35 *********************************************************************************************************
36 */
37
38 #if OS_Q_ACCEPT_EN > 0
39 void *OSQAccept (OS_EVENT *pevent) KCREENTRANT
40 {
41 1 #if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
42 1 OS_CPU_SR cpu_sr;
43 1 #endif
44 1 void *msg;
45 1 OS_Q *pq;
46 1
47 1
48 1 #if OS_ARG_CHK_EN > 0
49 1 if (pevent == (OS_EVENT *)0) { /* Validate 'pevent' */
50 2 return ((void *)0);
51 2 }
52 1 if (pevent->OSEventType != OS_EVENT_TYPE_Q) {/* Validate event block type */
53 2 return ((void *)0);
54 2 }
C51 COMPILER V8.02 OS_Q 05/22/2008 18:01:52 PAGE 2
55 1 #endif
56 1 OS_ENTER_CRITICAL();
57 1 pq = (OS_Q *)pevent->OSEventPtr; /* Point at queue control block */
58 1 if (pq->OSQEntries > 0) { /* See if any messages in the queue */
59 2 msg = *pq->OSQOut++; /* Yes, extract oldest message from the queue */
60 2 pq->OSQEntries--; /* Update the number of entries in the queue */
61 2 if (pq->OSQOut == pq->OSQEnd) { /* Wrap OUT pointer if we are at the end of the queue */
62 3 pq->OSQOut = pq->OSQStart;
63 3 }
64 2 } else {
65 2 msg = (void *)0; /* Queue is empty */
66 2 }
67 1 OS_EXIT_CRITICAL();
68 1 return (msg); /* Return message received (or NULL) */
69 1 }
70 #endif
71 /*$PAGE*/
72 /*
73 *********************************************************************************************************
74 * CREATE A MESSAGE QUEUE
75 *
76 * Description: This function creates a message queue if free event control blocks are available.
77 *
78 * Arguments : start is a pointer to the base address of the message queue storage area. The
79 * storage area MUST be declared as an array of pointers to 'void' as follows
80 *
81 * void *MessageStorage[size]
82 *
83 * size is the number of elements in the storage area
84 *
85 * Returns : != (OS_EVENT *)0 is a pointer to the event control clock (OS_EVENT) associated with the
86 * created queue
87 * == (OS_EVENT *)0 if no event control blocks were available or an error was detected
88 *********************************************************************************************************
89 */
90
91 OS_EVENT *OSQCreate (void **start, INT16U size) KCREENTRANT
92 {
93 1 #if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
94 1 OS_CPU_SR cpu_sr;
95 1 #endif
96 1 OS_EVENT *pevent;
97 1 OS_Q *pq;
98 1
99 1
100 1 if (OSIntNesting > 0) { /* See if called from ISR ... */
101 2 return ((OS_EVENT *)0); /* ... can't CREATE from an ISR */
102 2 }
103 1 OS_ENTER_CRITICAL();
104 1 pevent = OSEventFreeList; /* Get next free event control block */
105 1 if (OSEventFreeList != (OS_EVENT *)0) { /* See if pool of free ECB pool was empty */
106 2 OSEventFreeList = (OS_EVENT *)OSEventFreeList->OSEventPtr;
107 2 }
108 1 OS_EXIT_CRITICAL();
109 1 if (pevent != (OS_EVENT *)0) { /* See if we have an event control block */
110 2 OS_ENTER_CRITICAL();
111 2 pq = OSQFreeList; /* Get a free queue control block */
112 2 if (pq != (OS_Q *)0) { /* Were we able to get a queue control block ? */
113 3 OSQFreeList = OSQFreeList->OSQPtr; /* Yes, Adjust free list pointer to next free*/
114 3 OS_EXIT_CRITICAL();
115 3 pq->OSQStart = start; /* Initialize the queue */
116 3 pq->OSQEnd = &start[size];
C51 COMPILER V8.02 OS_Q 05/22/2008 18:01:52 PAGE 3
117 3 pq->OSQIn = start;
118 3 pq->OSQOut = start;
119 3 pq->OSQSize = size;
120 3 pq->OSQEntries = 0;
121 3 pevent->OSEventType = OS_EVENT_TYPE_Q;
122 3 pevent->OSEventCnt = 0;
123 3 pevent->OSEventPtr = pq;
124 3 OS_EventWaitListInit(pevent); /* Initalize the wait list */
125 3 } else {
126 3 pevent->OSEventPtr = (void *)OSEventFreeList; /* No, Return event control block on error */
127 3 OSEventFreeList = pevent;
128 3 OS_EXIT_CRITICAL();
129 3 pevent = (OS_EVENT *)0;
130 3 }
131 2 }
132 1 return (pevent);
133 1 }
134 /*$PAGE*/
135 /*
136 *********************************************************************************************************
137 * DELETE A MESSAGE QUEUE
138 *
139 * Description: This function deletes a message queue and readies all tasks pending on the queue.
140 *
141 * Arguments : pevent is a pointer to the event control block associated with the desired
142 * queue.
143 *
144 * opt determines delete options as follows:
145 * opt == OS_DEL_NO_PEND Delete the queue ONLY if no task pending
146 * opt == OS_DEL_ALWAYS Deletes the queue even if tasks are waiting.
147 * In this case, all the tasks pending will be readied.
148 *
149 * err is a pointer to an error code that can contain one of the following values:
150 * OS_NO_ERR The call was successful and the queue was deleted
151 * OS_ERR_DEL_ISR If you tried to delete the queue from an ISR
152 * OS_ERR_INVALID_OPT An invalid option was specified
153 * OS_ERR_TASK_WAITING One or more tasks were waiting on the queue
154 * OS_ERR_EVENT_TYPE If you didn't pass a pointer to a queue
155 * OS_ERR_PEVENT_NULL If 'pevent' is a NULL pointer.
156 *
157 * Returns : pevent upon error
158 * (OS_EVENT *)0 if the queue was successfully deleted.
159 *
160 * Note(s) : 1) This function must be used with care. Tasks that would normally expect the presence of
161 * the queue MUST check the return code of OSQPend().
162 * 2) OSQAccept() callers will not know that the intended queue has been deleted unless
163 * they check 'pevent' to see that it's a NULL pointer.
164 * 3) This call can potentially disable interrupts for a long time. The interrupt disable
165 * time is directly proportional to the number of tasks waiting on the queue.
166 * 4) Because ALL tasks pending on the queue will be readied, you MUST be careful in
167 * applications where the queue is used for mutual exclusion because the resource(s)
168 * will no longer be guarded by the queue.
169 * 5) If the storage for the message queue was allocated dynamically (i.e. using a malloc()
170 * type call) then your application MUST release the memory storage by call the counterpart
171 * call of the dynamic allocation scheme used. If the queue storage was created statically
172 * then, the storage can be reused.
173 *********************************************************************************************************
174 */
175
176 #if OS_Q_DEL_EN > 0
177 OS_EVENT *OSQDel (OS_EVENT *pevent, INT8U opt, INT8U *err) KCREENTRANT
178 {
C51 COMPILER V8.02 OS_Q 05/22/2008 18:01:52 PAGE 4
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