?? os_mbox.lst
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C51 COMPILER V7.20 OS_MBOX 06/15/2006 16:15:50 PAGE 1
C51 COMPILER V7.20, COMPILATION OF MODULE OS_MBOX
OBJECT MODULE PLACED IN OS_MBOX.OBJ
COMPILER INVOKED BY: d:\Keil\C51\BIN\C51.EXE OS_MBOX.C LARGE BROWSE DEBUG OBJECTEXTEND
line level source
1 /*
2 *********************************************************************************************************
3 * uC/OS-II
4 * The Real-Time Kernel
5 * MESSAGE MAILBOX MANAGEMENT
6 *
7 * (c) Copyright 1992-2002, 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 "ucos_ii.h"
17 #endif
18
19 #if OS_MBOX_EN > 0
20 /*
21 *********************************************************************************************************
22 * ACCEPT MESSAGE FROM MAILBOX
23 *
24 * Description: This function checks the mailbox to see if a message is available. Unlike OSMboxPend(),
25 * OSMboxAccept() 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 mailbox if one is available. The mailbox is cleared
30 * so the next time OSMboxAccept() is called, the mailbox will be empty.
31 * == (void *)0 if the mailbox is empty or,
32 * if 'pevent' is a NULL pointer or,
33 * if you didn't pass the proper event pointer.
34 *********************************************************************************************************
35 */
36
37 #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();
msg = pevent->OSEventPtr;
C51 COMPILER V7.20 OS_MBOX 06/15/2006 16:15:50 PAGE 2
pevent->OSEventPtr = (void *)0; /* Clear the mailbox */
OS_EXIT_CRITICAL();
return (msg); /* Return the message received (or NULL) */
}
#endif
61 /*$PAGE*/
62 /*
63 *********************************************************************************************************
64 * CREATE A MESSAGE MAILBOX
65 *
66 * Description: This function creates a message mailbox if free event control blocks are available.
67 *
68 * Arguments : msg is a pointer to a message that you wish to deposit in the mailbox. If
69 * you set this value to the NULL pointer (i.e. (void *)0) then the mailbox
70 * will be considered empty.
71 *
72 * Returns : != (OS_EVENT *)0 is a pointer to the event control clock (OS_EVENT) associated with the
73 * created mailbox
74 * == (OS_EVENT *)0 if no event control blocks were available
75 *********************************************************************************************************
76 */
77 #if OS_MBOX_CREATE_EN>0
78 OS_EVENT *OSMboxCreate (void *msg) reentrant
79 {
80 1 #if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
83 1 OS_EVENT *pevent;
84 1
85 1
86 1 if (OSIntNesting > 0) { /* See if called from ISR ... */
87 2 return ((OS_EVENT *)0); /* ... can't CREATE from an ISR */
88 2 }
89 1 OS_ENTER_CRITICAL();
90 1 pevent = OSEventFreeList; /* Get next free event control block */
91 1 if (OSEventFreeList != (OS_EVENT *)0) { /* See if pool of free ECB pool was empty */
92 2 OSEventFreeList = (OS_EVENT *)OSEventFreeList->OSEventPtr;
93 2 }
94 1 OS_EXIT_CRITICAL();
95 1 if (pevent != (OS_EVENT *)0) {
96 2 pevent->OSEventType = OS_EVENT_TYPE_MBOX;
97 2 pevent->OSEventCnt = 0;
98 2 pevent->OSEventPtr = msg; /* Deposit message in event control block */
99 2 OS_EventWaitListInit(pevent);
100 2 }
101 1 return (pevent); /* Return pointer to event control block */
102 1 }
103 #endif
104 /*$PAGE*/
105 /*
106 *********************************************************************************************************
107 * DELETE A MAIBOX
108 *
109 * Description: This function deletes a mailbox and readies all tasks pending on the mailbox.
110 *
111 * Arguments : pevent is a pointer to the event control block associated with the desired
112 * mailbox.
113 *
114 * opt determines delete options as follows:
115 * opt == OS_DEL_NO_PEND Delete the mailbox ONLY if no task pending
116 * opt == OS_DEL_ALWAYS Deletes the mailbox even if tasks are waiting.
117 * In this case, all the tasks pending will be readied.
C51 COMPILER V7.20 OS_MBOX 06/15/2006 16:15:50 PAGE 3
118 *
119 * err is a pointer to an error code that can contain one of the following values:
120 * OS_NO_ERR The call was successful and the mailbox was deleted
121 * OS_ERR_DEL_ISR If you attempted to delete the mailbox from an ISR
122 * OS_ERR_INVALID_OPT An invalid option was specified
123 * OS_ERR_TASK_WAITING One or more tasks were waiting on the mailbox
124 * OS_ERR_EVENT_TYPE If you didn't pass a pointer to a mailbox
125 * OS_ERR_PEVENT_NULL If 'pevent' is a NULL pointer.
126 *
127 * Returns : pevent upon error
128 * (OS_EVENT *)0 if the mailbox was successfully deleted.
129 *
130 * Note(s) : 1) This function must be used with care. Tasks that would normally expect the presence of
131 * the mailbox MUST check the return code of OSMboxPend().
132 * 2) OSMboxAccept() callers will not know that the intended mailbox has been deleted!
133 * 3) This call can potentially disable interrupts for a long time. The interrupt disable
134 * time is directly proportional to the number of tasks waiting on the mailbox.
135 * 4) Because ALL tasks pending on the mailbox will be readied, you MUST be careful in
136 * applications where the mailbox is used for mutual exclusion because the resource(s)
137 * will no longer be guarded by the mailbox.
138 *********************************************************************************************************
139 */
140
141 #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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