?? os_mutex.lst
字號(hào):
C51 COMPILER V7.06 OS_MUTEX 07/18/2003 11:06:01 PAGE 1
C51 COMPILER V7.06, COMPILATION OF MODULE OS_MUTEX
OBJECT MODULE PLACED IN .\os_mutex.obj
COMPILER INVOKED BY: C:\KEIL\C51\BIN\C51.EXE ..\keilc51\os_mutex.c LARGE BROWSE DEBUG OBJECTEXTEND PRINT(.\os_mutex.lst)
- OBJECT(.\os_mutex.obj)
stmt level source
1 /*
2 *********************************************************************************************************
3 * uC/OS-II
4 * The Real-Time Kernel
5 * MUTUAL EXCLUSION SEMAPHORE MANAGEMENT
6 *
7 * (c) Copyright 1992-2002, Jean J. Labrosse, Weston, FL
8 * All Rights Reserved
9 *
10 * File : OS_MUTEX.C
11 * By : Jean J. Labrosse
12 *********************************************************************************************************
13 */
14
15 #ifndef OS_MASTER_FILE
16 #include "includes.h"
17 #endif
18
19 /*
20 *********************************************************************************************************
21 * LOCAL CONSTANTS
22 *********************************************************************************************************
23 */
24
25 #define OS_MUTEX_KEEP_LOWER_8 0x00FF
26 #define OS_MUTEX_KEEP_UPPER_8 0xFF00
27
28 #define OS_MUTEX_AVAILABLE 0x00FF
29
30
31 #if OS_MUTEX_EN > 0
32 /*
33 *********************************************************************************************************
34 * ACCEPT MUTUAL EXCLUSION SEMAPHORE
35 *
36 * Description: This function checks the mutual exclusion semaphore to see if a resource is available.
37 * Unlike OSMutexPend(), OSMutexAccept() does not suspend the calling task if the resource is
38 * not available or the event did not occur.
39 *
40 * Arguments : pevent is a pointer to the event control block
41 *
42 * err is a pointer to an error code which will be returned to your application:
43 * OS_NO_ERR if the call was successful.
44 * OS_ERR_EVENT_TYPE if 'pevent' is not a pointer to a mutex
45 * OS_ERR_PEVENT_NULL 'pevent' is a NULL pointer
46 * OS_ERR_PEND_ISR if you called this function from an ISR
47 *
48 * Returns : == 1 if the resource is available, the mutual exclusion semaphore is acquired
49 * == 0 a) if the resource is not available
50 * b) you didn't pass a pointer to a mutual exclusion semaphore
51 * c) you called this function from an ISR
52 *
53 * Warning(s) : This function CANNOT be called from an ISR because mutual exclusion semaphores are
54 * intended to be used by tasks only.
C51 COMPILER V7.06 OS_MUTEX 07/18/2003 11:06:01 PAGE 2
55 *********************************************************************************************************
56 */
57
58 #if OS_MUTEX_ACCEPT_EN > 0
59 INT8U OSMutexAccept (OS_EVENT *pevent, INT8U *err) reentrant //using 0
60 {
61 1 #if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
62 1 OS_CPU_SR cpu_sr;
63 1 #endif
64 1
65 1
66 1 if (OSIntNesting > 0) { /* Make sure it's not called from an ISR */
67 2 *err = OS_ERR_PEND_ISR;
68 2 return (0);
69 2 }
70 1 #if OS_ARG_CHK_EN > 0
71 1 if (pevent == (OS_EVENT *)0) { /* Validate 'pevent' */
72 2 *err = OS_ERR_PEVENT_NULL;
73 2 return (0);
74 2 }
75 1 #endif
76 1 if (pevent->OSEventType != OS_EVENT_TYPE_MUTEX) { /* Validate event block type */
77 2 *err = OS_ERR_EVENT_TYPE;
78 2 return (0);
79 2 }
80 1 OS_ENTER_CRITICAL(); /* Get value (0 or 1) of Mutex */
81 1 if ((pevent->OSEventCnt & OS_MUTEX_KEEP_LOWER_8) == OS_MUTEX_AVAILABLE) {
82 2 pevent->OSEventCnt &= OS_MUTEX_KEEP_UPPER_8; /* Mask off LSByte (Acquire Mutex) */
83 2 pevent->OSEventCnt |= OSTCBCur->OSTCBPrio; /* Save current task priority in LSByte */
84 2 pevent->OSEventPtr = (void *)OSTCBCur; /* Link TCB of task owning Mutex */
85 2 OS_EXIT_CRITICAL();
86 2 *err = OS_NO_ERR;
87 2 return (1);
88 2 }
89 1 OS_EXIT_CRITICAL();
90 1 *err = OS_NO_ERR;
91 1 return (0);
92 1 }
93 #endif
94
95 /*$PAGE*/
96 /*
97 *********************************************************************************************************
98 * CREATE A MUTUAL EXCLUSION SEMAPHORE
99 *
100 * Description: This function creates a mutual exclusion semaphore.
101 *
102 * Arguments : prio is the priority to use when accessing the mutual exclusion semaphore. In
103 * other words, when the semaphore is acquired and a higher priority task
104 * attempts to obtain the semaphore then the priority of the task owning the
105 * semaphore is raised to this priority. It is assumed that you will specify
106 * a priority that is LOWER in value than ANY of the tasks competing for the
107 * mutex.
108 *
109 * err is a pointer to an error code which will be returned to your application:
110 * OS_NO_ERR if the call was successful.
111 * OS_ERR_CREATE_ISR if you attempted to create a MUTEX from an ISR
112 * OS_PRIO_EXIST if a task at the priority inheritance priority
113 * already exist.
114 * OS_ERR_PEVENT_NULL No more event control blocks available.
115 * OS_PRIO_INVALID if the priority you specify is higher that the
116 * maximum allowed (i.e. > OS_LOWEST_PRIO)
C51 COMPILER V7.06 OS_MUTEX 07/18/2003 11:06:01 PAGE 3
117 *
118 * Returns : != (void *)0 is a pointer to the event control clock (OS_EVENT) associated with the
119 * created mutex.
120 * == (void *)0 if an error is detected.
121 *
122 * Note(s) : 1) The LEAST significant 8 bits of '.OSEventCnt' are used to hold the priority number
123 * of the task owning the mutex or 0xFF if no task owns the mutex.
124 * 2) The MOST significant 8 bits of '.OSEventCnt' are used to hold the priority number
125 * to use to reduce priority inversion.
126 *********************************************************************************************************
127 */
128
129 OS_EVENT *OSMutexCreate (INT8U prio, INT8U *err) reentrant //using 0
130 {
131 1 #if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
132 1 OS_CPU_SR cpu_sr;
133 1 #endif
134 1 OS_EVENT *pevent;
135 1
136 1
137 1 if (OSIntNesting > 0) { /* See if called from ISR ... */
138 2 *err = OS_ERR_CREATE_ISR; /* ... can't CREATE mutex from an ISR */
139 2 return ((OS_EVENT *)0);
140 2 }
141 1 #if OS_ARG_CHK_EN > 0
142 1 if (prio >= OS_LOWEST_PRIO) { /* Validate PIP */
143 2 *err = OS_PRIO_INVALID;
144 2 return ((OS_EVENT *)0);
145 2 }
146 1 #endif
147 1 OS_ENTER_CRITICAL();
148 1 if (OSTCBPrioTbl[prio] != (OS_TCB *)0) { /* Mutex priority must not already exist */
149 2 OS_EXIT_CRITICAL(); /* Task already exist at priority ... */
150 2 *err = OS_PRIO_EXIST; /* ... inheritance priority */
151 2 return ((OS_EVENT *)0);
152 2 }
153 1 OSTCBPrioTbl[prio] = (OS_TCB *)1; /* Reserve the table entry */
154 1 pevent = OSEventFreeList; /* Get next free event control block */
155 1 if (pevent == (OS_EVENT *)0) { /* See if an ECB was available */
156 2 OSTCBPrioTbl[prio] = (OS_TCB *)0; /* No, Release the table entry */
157 2 OS_EXIT_CRITICAL();
158 2 *err = OS_ERR_PEVENT_NULL; /* No more event control blocks */
159 2 return (pevent);
160 2 }
161 1 OSEventFreeList = (OS_EVENT *)OSEventFreeList->OSEventPtr; /* Adjust the free list */
162 1 OS_EXIT_CRITICAL();
163 1 pevent->OSEventType = OS_EVENT_TYPE_MUTEX;
164 1 pevent->OSEventCnt = ((INT16U)prio << 8) | OS_MUTEX_AVAILABLE; /* Resource is available */
165 1 pevent->OSEventPtr = (void *)0; /* No task owning the mutex */
166 1 #if OS_EVENT_NAME_SIZE > 0
167 1 (void)strcpy(pevent->OSEventName, "?");
168 1 #endif
169 1 OS_EventWaitListInit(pevent);
170 1 *err = OS_NO_ERR;
171 1 return (pevent);
172 1 }
173
174 /*$PAGE*/
175 /*
176 *********************************************************************************************************
177 * DELETE A MUTEX
178 *
C51 COMPILER V7.06 OS_MUTEX 07/18/2003 11:06:01 PAGE 4
179 * Description: This function deletes a mutual exclusion semaphore and readies all tasks pending on the it.
180 *
181 * Arguments : pevent is a pointer to the event control block associated with the desired mutex.
182 *
183 * opt determines delete options as follows:
184 * opt == OS_DEL_NO_PEND Delete mutex ONLY if no task pending
185 * opt == OS_DEL_ALWAYS Deletes the mutex even if tasks are waiting.
186 * In this case, all the tasks pending will be readied.
187 *
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