os_mbox.src

uCOS-II_2.52在51上的移植程序

; .\OS_MBOX.SRC generated from: OS_MBOX.C
; COMPILER INVOKED BY:
;        C:\Keil\C51\BIN\C51.EXE OS_MBOX.C LARGE BROWSE ORDER NOAREGS DEBUG OBJECTEXTEND SRC(.\OS_MBOX.SRC)

$NOMOD51

NAME	OS_MBOX

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TL1	DATA	08BH
TH0	DATA	08CH
TH1	DATA	08DH
IE	DATA	0A8H
IP	DATA	0B8H
SCON	DATA	098H
SBUF	DATA	099H
CY	BIT	0D0H.7
AC	BIT	0D0H.6
F0	BIT	0D0H.5
RS1	BIT	0D0H.4
RS0	BIT	0D0H.3
OV	BIT	0D0H.2
P	BIT	0D0H.0
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TR1	BIT	088H.6
TF0	BIT	088H.5
TR0	BIT	088H.4
IE1	BIT	088H.3
IT1	BIT	088H.2
IE0	BIT	088H.1
IT0	BIT	088H.0
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ES	BIT	0A8H.4
ET1	BIT	0A8H.3
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ET0	BIT	0A8H.1
EX0	BIT	0A8H.0
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PT1	BIT	0B8H.3
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PT0	BIT	0B8H.1
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INT0	BIT	0B0H.2
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RXD	BIT	0B0H.0
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SM1	BIT	098H.6
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TI	BIT	098H.1
RI	BIT	098H.0
; /*
; *********************************************************************************************************
; *                                                uC/OS-II
; *                                          The Real-Time Kernel
; *                                       MESSAGE MAILBOX MANAGEMENT
; *
; *                          (c) Copyright 1992-2002, Jean J. Labrosse, Weston, FL
; *                                           All Rights Reserved
; *
; * File : OS_MBOX.C
; * By   : Jean J. Labrosse
; *********************************************************************************************************
; */
; 
; #ifndef  OS_MASTER_FILE
; #include "includes.h"
; #endif
; 
; #if OS_MBOX_EN > 0
; /*
; *********************************************************************************************************
; *                                     ACCEPT MESSAGE FROM MAILBOX
; *
; * Description: This function checks the mailbox to see if a message is available.  Unlike OSMboxPend(),
; *              OSMboxAccept() does not suspend the calling task if a message is not available.
; *
; * Arguments  : pevent        is a pointer to the event control block
; *
; * Returns    : != (void *)0  is the message in the mailbox if one is available.  The mailbox is cleared
; *                            so the next time OSMboxAccept() is called, the mailbox will be empty.
; *              == (void *)0  if the mailbox is empty or,
; *                            if 'pevent' is a NULL pointer or,
; *                            if you didn't pass the proper event pointer.
; *********************************************************************************************************
; */
; 
; #if OS_MBOX_ACCEPT_EN > 0
; void  *OSMboxAccept (OS_EVENT *pevent)
; {
;    
;     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;
;     pevent->OSEventPtr = (void *)0;                       /* Clear the mailbox                         */
;     OS_EXIT_CRITICAL();
;     return (msg);                                         /* Return the message received (or NULL)     */
; }
; #endif
; /*$PAGE*/
; /*
; *********************************************************************************************************
; *                                        CREATE A MESSAGE MAILBOX
; *
; * Description: This function creates a message mailbox if free event control blocks are available.
; *
; * Arguments  : msg           is a pointer to a message that you wish to deposit in the mailbox.  If
; *                            you set this value to the NULL pointer (i.e. (void *)0) then the mailbox
; *                            will be considered empty.
; *
; * Returns    : != (OS_EVENT *)0  is a pointer to the event control clock (OS_EVENT) associated with the
; *                                created mailbox
; *              == (OS_EVENT *)0  if no event control blocks were available
; *********************************************************************************************************
; */
; 
; OS_EVENT  *OSMboxCreate (void *msg)
; {  
;     OS_EVENT  *pevent;
; 
; 
;     if (OSIntNesting > 0) {                      /* See if called from ISR ...                         */
;         return ((OS_EVENT *)0);                  /* ... can't CREATE from an ISR                       */
;     }
;     OS_ENTER_CRITICAL();
;     pevent = OSEventFreeList;                    /* Get next free event control block                  */
;     if (OSEventFreeList != (OS_EVENT *)0) {      /* See if pool of free ECB pool was empty             */
;         OSEventFreeList = (OS_EVENT *)OSEventFreeList->OSEventPtr;
;     }
;     OS_EXIT_CRITICAL();
;     if (pevent != (OS_EVENT *)0) {
;         pevent->OSEventType = OS_EVENT_TYPE_MBOX;
;         pevent->OSEventCnt  = 0;
;         pevent->OSEventPtr  = msg;               /* Deposit message in event control block             */
;         OS_EventWaitListInit(pevent);
;     }
;     return (pevent);                             /* Return pointer to event control block              */
; }
; /*$PAGE*/
; /*
; *********************************************************************************************************
; *                                         DELETE A MAIBOX
; *
; * Description: This function deletes a mailbox and readies all tasks pending on the mailbox.
; *
; * Arguments  : pevent        is a pointer to the event control block associated with the desired
; *                            mailbox.
; *
; *              opt           determines delete options as follows:
; *                            opt == OS_DEL_NO_PEND   Delete the mailbox ONLY if no task pending
; *                            opt == OS_DEL_ALWAYS    Deletes the mailbox even if tasks are waiting.
; *                                                    In this case, all the tasks pending will be readied.
; *
; *              err           is a pointer to an error code that can contain one of the following values:
; *                            OS_NO_ERR               The call was successful and the mailbox was deleted
; *                            OS_ERR_DEL_ISR          If you attempted to delete the mailbox from an ISR
; *                            OS_ERR_INVALID_OPT      An invalid option was specified
; *                            OS_ERR_TASK_WAITING     One or more tasks were waiting on the mailbox
; *                            OS_ERR_EVENT_TYPE       If you didn't pass a pointer to a mailbox
; *                            OS_ERR_PEVENT_NULL      If 'pevent' is a NULL pointer.
; *
; * Returns    : pevent        upon error
; *              (OS_EVENT *)0 if the mailbox was successfully deleted.
; *
; * Note(s)    : 1) This function must be used with care.  Tasks that would normally expect the presence of
; *                 the mailbox MUST check the return code of OSMboxPend().
; *              2) OSMboxAccept() callers will not know that the intended mailbox has been deleted!
; *              3) This call can potentially disable interrupts for a long time.  The interrupt disable
; *                 time is directly proportional to the number of tasks waiting on the mailbox.
; *              4) Because ALL tasks pending on the mailbox will be readied, you MUST be careful in
; *                 applications where the mailbox is used for mutual exclusion because the resource(s)
; *                 will no longer be guarded by the mailbox.
; *********************************************************************************************************
; */
; 
; #if OS_MBOX_DEL_EN > 0
; OS_EVENT  *OSMboxDel (OS_EVENT *pevent, INT8U opt, INT8U *err)
; {
;    
;     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                                      */
;     } else {
;         tasks_waiting = FALSE;                             /* No                                       */
;     }
;     switch (opt) {
;         case OS_DEL_NO_PEND:                               /* Delete mailbox only if no task waiting   */
;              if (tasks_waiting == FALSE) {
;                  pevent->OSEventType = OS_EVENT_TYPE_UNUSED;
;                  pevent->OSEventPtr  = OSEventFreeList;    /* Return Event Control Block to free list  */
;                  OSEventFreeList     = pevent;             /* Get next free event control block        */
;                  OS_EXIT_CRITICAL();
;                  *err = OS_NO_ERR;
;                  return ((OS_EVENT *)0);                   /* Mailbox has been deleted                 */
;              } else {
;                  OS_EXIT_CRITICAL();
;                  *err = OS_ERR_TASK_WAITING;
;                  return (pevent);
;              }
; 
;         case OS_DEL_ALWAYS:                                /* Always delete the mailbox                */
;              while (pevent->OSEventGrp != 0x00) {          /* Ready ALL tasks waiting for mailbox      */
;                  OS_EventTaskRdy(pevent, (void *)0, OS_STAT_MBOX);
;              }
;              pevent->OSEventType = OS_EVENT_TYPE_UNUSED;
;              pevent->OSEventPtr  = OSEventFreeList;        /* Return Event Control Block to free list  */
;              OSEventFreeList     = pevent;                 /* Get next free event control block        */
;              OS_EXIT_CRITICAL();
;              if (tasks_waiting == TRUE) {                  /* Reschedule only if task(s) were waiting  */
;                  OS_Sched();                               /* Find highest priority task ready to run  */
;              }
;              *err = OS_NO_ERR;
;              return ((OS_EVENT *)0);                       /* Mailbox has been deleted                 */
; 
;         default:
;              OS_EXIT_CRITICAL();
;              *err = OS_ERR_INVALID_OPT;
;              return (pevent);
;     }
; }
; #endif
; 
; /*$PAGE*/
; /*
; *********************************************************************************************************
; *                                      PEND ON MAILBOX FOR A MESSAGE
; *
; * Description: This function waits for a message to be sent to a mailbox
; *
; * Arguments  : pevent        is a pointer to the event control block associated with the desired mailbox