📄 os_q.lst
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C51 COMPILER V7.50 OS_Q 12/14/2007 08:25:37 PAGE 1
C51 COMPILER V7.50, COMPILATION OF MODULE OS_Q
OBJECT MODULE PLACED IN OS_Q.OBJ
COMPILER INVOKED BY: C:\Keil\C51\BIN\C51.EXE OS_Q.C LARGE BROWSE DEBUG OBJECTEXTEND
line level source
1 /*
2 *********************************************************************************************************
3 * uC/OS-II
4 * The Real-Time Kernel
5 * MESSAGE QUEUE MANAGEMENT
6 *
7 * (c) Copyright 1992-2007, Jean J. Labrosse, Weston, FL
8 * All Rights Reserved
9 *
10 * File : OS_Q.C
11 * By : Jean J. Labrosse
12 * Version : V2.85
13 *
14 * LICENSING TERMS:
15 * ---------------
16 * uC/OS-II is provided in source form for FREE evaluation, for educational use or for peaceful research.
-
17 * If you plan on using uC/OS-II in a commercial product you need to contact Micri祄 to properly license
18 * its use in your product. We provide ALL the source code for your convenience and to help you experience
19 * uC/OS-II. The fact that the source is provided does NOT mean that you can use it without paying a
20 * licensing fee.
21 *********************************************************************************************************
22 */
23
24 #ifndef OS_MASTER_FILE
25 #include <ucos_ii.h>
26 #endif
27
28 #if (OS_Q_EN > 0) && (OS_MAX_QS > 0)
29 /*
30 *********************************************************************************************************
31 * ACCEPT MESSAGE FROM QUEUE
32 *
33 * Description: This function checks the queue to see if a message is available. Unlike OSQPend(),
34 * OSQAccept() does not suspend the calling task if a message is not available.
35 *
36 * Arguments : pevent is a pointer to the event control block
37 *
38 * perr is a pointer to where an error message will be deposited. Possible error
39 * messages are:
40 *
41 * OS_ERR_NONE The call was successful and your task received a
42 * message.
43 * OS_ERR_EVENT_TYPE You didn't pass a pointer to a queue
44 * OS_ERR_PEVENT_NULL If 'pevent' is a NULL pointer
45 * OS_ERR_Q_EMPTY The queue did not contain any messages
46 *
47 * Returns : != (void *)0 is the message in the queue if one is available. The message is removed
48 * from the so the next time OSQAccept() is called, the queue will contain
49 * one less entry.
50 * == (void *)0 if you received a NULL pointer message
51 * if the queue is empty or,
52 * if 'pevent' is a NULL pointer or,
53 * if you passed an invalid event type
54 *
C51 COMPILER V7.50 OS_Q 12/14/2007 08:25:37 PAGE 2
55 * Note(s) : As of V2.60, you can now pass NULL pointers through queues. Because of this, the argument
56 * 'perr' has been added to the API to tell you about the outcome of the call.
57 *********************************************************************************************************
58 */
59
60 #if OS_Q_ACCEPT_EN > 0
61 void *OSQAccept (OS_EVENT *pevent, INT8U *perr) reentrant
62 {
63 1 void *pmsg;
64 1 OS_Q *pq;
65 1 #if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr = 0;
#endif
68 1
69 1
70 1
71 1 #if OS_ARG_CHK_EN > 0
if (perr == (INT8U *)0) { /* Validate 'perr' */
return ((void *)0);
}
if (pevent == (OS_EVENT *)0) { /* Validate 'pevent' */
*perr = OS_ERR_PEVENT_NULL;
return ((void *)0);
}
#endif
80 1 if (pevent->OSEventType != OS_EVENT_TYPE_Q) {/* Validate event block type */
81 2 *perr = OS_ERR_EVENT_TYPE;
82 2 return ((void *)0);
83 2 }
84 1 OS_ENTER_CRITICAL();
85 1 pq = (OS_Q *)pevent->OSEventPtr; /* Point at queue control block */
86 1 if (pq->OSQEntries > 0) { /* See if any messages in the queue */
87 2 pmsg = *pq->OSQOut++; /* Yes, extract oldest message from the queue */
88 2 pq->OSQEntries--; /* Update the number of entries in the queue */
89 2 if (pq->OSQOut == pq->OSQEnd) { /* Wrap OUT pointer if we are at the end of the queue */
90 3 pq->OSQOut = pq->OSQStart;
91 3 }
92 2 *perr = OS_ERR_NONE;
93 2 } else {
94 2 *perr = OS_ERR_Q_EMPTY;
95 2 pmsg = (void *)0; /* Queue is empty */
96 2 }
97 1 OS_EXIT_CRITICAL();
98 1 return (pmsg); /* Return message received (or NULL) */
99 1 }
100 #endif
101 /*$PAGE*/
102 /*
103 *********************************************************************************************************
104 * CREATE A MESSAGE QUEUE
105 *
106 * Description: This function creates a message queue if free event control blocks are available.
107 *
108 * Arguments : start is a pointer to the base address of the message queue storage area. The
109 * storage area MUST be declared as an array of pointers to 'void' as follows
110 *
111 * void *MessageStorage[size]
112 *
113 * size is the number of elements in the storage area
114 *
115 * Returns : != (OS_EVENT *)0 is a pointer to the event control clock (OS_EVENT) associated with the
116 * created queue
C51 COMPILER V7.50 OS_Q 12/14/2007 08:25:37 PAGE 3
117 * == (OS_EVENT *)0 if no event control blocks were available or an error was detected
118 *********************************************************************************************************
119 */
120
121 OS_EVENT *OSQCreate (void **start, INT16U size) reentrant
122 {
123 1 OS_EVENT *pevent;
124 1 OS_Q *pq;
125 1 #if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr = 0;
#endif
128 1
129 1
130 1
131 1 if (OSIntNesting > 0) { /* See if called from ISR ... */
132 2 return ((OS_EVENT *)0); /* ... can't CREATE from an ISR */
133 2 }
134 1 OS_ENTER_CRITICAL();
135 1 pevent = OSEventFreeList; /* Get next free event control block */
136 1 if (OSEventFreeList != (OS_EVENT *)0) { /* See if pool of free ECB pool was empty */
137 2 OSEventFreeList = (OS_EVENT *)OSEventFreeList->OSEventPtr;
138 2 }
139 1 OS_EXIT_CRITICAL();
140 1 if (pevent != (OS_EVENT *)0) { /* See if we have an event control block */
141 2 OS_ENTER_CRITICAL();
142 2 pq = OSQFreeList; /* Get a free queue control block */
143 2 if (pq != (OS_Q *)0) { /* Were we able to get a queue control block ? */
144 3 OSQFreeList = OSQFreeList->OSQPtr; /* Yes, Adjust free list pointer to next free*/
145 3 OS_EXIT_CRITICAL();
146 3 pq->OSQStart = start; /* Initialize the queue */
147 3 pq->OSQEnd = &start[size];
148 3 pq->OSQIn = start;
149 3 pq->OSQOut = start;
150 3 pq->OSQSize = size;
151 3 pq->OSQEntries = 0;
152 3 pevent->OSEventType = OS_EVENT_TYPE_Q;
153 3 pevent->OSEventCnt = 0;
154 3 pevent->OSEventPtr = pq;
155 3 #if OS_EVENT_NAME_SIZE > 1
156 3 pevent->OSEventName[0] = '?'; /* Unknown name */
157 3 pevent->OSEventName[1] = OS_ASCII_NUL;
158 3 #endif
159 3 OS_EventWaitListInit(pevent); /* Initalize the wait list */
160 3 } else {
161 3 pevent->OSEventPtr = (void *)OSEventFreeList; /* No, Return event control block on error */
162 3 OSEventFreeList = pevent;
163 3 OS_EXIT_CRITICAL();
164 3 pevent = (OS_EVENT *)0;
165 3 }
166 2 }
167 1 return (pevent);
168 1 }
169 /*$PAGE*/
170 /*
171 *********************************************************************************************************
172 * DELETE A MESSAGE QUEUE
173 *
174 * Description: This function deletes a message queue and readies all tasks pending on the queue.
175 *
176 * Arguments : pevent is a pointer to the event control block associated with the desired
177 * queue.
178 *
C51 COMPILER V7.50 OS_Q 12/14/2007 08:25:37 PAGE 4
179 * opt determines delete options as follows:
180 * opt == OS_DEL_NO_PEND Delete the queue ONLY if no task pending
181 * opt == OS_DEL_ALWAYS Deletes the queue even if tasks are waiting.
182 * In this case, all the tasks pending will be readied.
183 *
184 * perr is a pointer to an error code that can contain one of the following values:
185 * OS_ERR_NONE The call was successful and the queue was deleted
186 * OS_ERR_DEL_ISR If you tried to delete the queue from an ISR
187 * OS_ERR_INVALID_OPT An invalid option was specified
188 * OS_ERR_TASK_WAITING One or more tasks were waiting on the queue
189 * OS_ERR_EVENT_TYPE If you didn't pass a pointer to a queue
190 * OS_ERR_PEVENT_NULL If 'pevent' is a NULL pointer.
191 *
192 * Returns : pevent upon error
193 * (OS_EVENT *)0 if the queue was successfully deleted.
194 *
195 * Note(s) : 1) This function must be used with care. Tasks that would normally expect the presence of
196 * the queue MUST check the return code of OSQPend().
197 * 2) OSQAccept() callers will not know that the intended queue has been deleted unless
198 * they check 'pevent' to see that it's a NULL pointer.
199 * 3) This call can potentially disable interrupts for a long time. The interrupt disable
200 * time is directly proportional to the number of tasks waiting on the queue.
201 * 4) Because ALL tasks pending on the queue will be readied, you MUST be careful in
202 * applications where the queue is used for mutual exclusion because the resource(s)
203 * will no longer be guarded by the queue.
204 * 5) If the storage for the message queue was allocated dynamically (i.e. using a malloc()
205 * type call) then your application MUST release the memory storage by call the counterpart
206 * call of the dynamic allocation scheme used. If the queue storage was created statically
207 * then, the storage can be reused.
208 *********************************************************************************************************
209 */
210
211 #if OS_Q_DEL_EN > 0
212 OS_EVENT *OSQDel (OS_EVENT *pevent, INT8U opt, INT8U *perr) reentrant
213 {
214 1 BOOLEAN tasks_waiting;
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