os_sem.src

uCOS-II_2.52在51上的移植程序

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

$NOMOD51

NAME	OS_SEM

P0	DATA	080H
P1	DATA	090H
P2	DATA	0A0H
P3	DATA	0B0H
PSW	DATA	0D0H
ACC	DATA	0E0H
B	DATA	0F0H
SP	DATA	081H
DPL	DATA	082H
DPH	DATA	083H
PCON	DATA	087H
TCON	DATA	088H
TMOD	DATA	089H
TL0	DATA	08AH
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
TF1	BIT	088H.7
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
EA	BIT	0A8H.7
ES	BIT	0A8H.4
ET1	BIT	0A8H.3
EX1	BIT	0A8H.2
ET0	BIT	0A8H.1
EX0	BIT	0A8H.0
PS	BIT	0B8H.4
PT1	BIT	0B8H.3
PX1	BIT	0B8H.2
PT0	BIT	0B8H.1
PX0	BIT	0B8H.0
RD	BIT	0B0H.7
WR	BIT	0B0H.6
T1	BIT	0B0H.5
T0	BIT	0B0H.4
INT1	BIT	0B0H.3
INT0	BIT	0B0H.2
TXD	BIT	0B0H.1
RXD	BIT	0B0H.0
SM0	BIT	098H.7
SM1	BIT	098H.6
SM2	BIT	098H.5
REN	BIT	098H.4
TB8	BIT	098H.3
RB8	BIT	098H.2
TI	BIT	098H.1
RI	BIT	098H.0
; /*
; *********************************************************************************************************
; *                                                uC/OS-II
; *                                          The Real-Time Kernel
; *                                          SEMAPHORE MANAGEMENT
; *
; *                          (c) Copyright 1992-2002, Jean J. Labrosse, Weston, FL
; *                                           All Rights Reserved
; *
; * File : OS_SEM.C
; * By   : Jean J. Labrosse
; *********************************************************************************************************
; */
; 
; #ifndef  OS_MASTER_FILE
; #include "includes.h"
; #endif
; 
; #if OS_SEM_EN > 0
; /*
; *********************************************************************************************************
; *                                           ACCEPT SEMAPHORE
; *
; * Description: This function checks the semaphore to see if a resource is available or, if an event
; *              occurred.  Unlike OSSemPend(), OSSemAccept() does not suspend the calling task if the
; *              resource is not available or the event did not occur.
; *
; * Arguments  : pevent     is a pointer to the event control block
; *
; * Returns    : >  0       if the resource is available or the event did not occur the semaphore is
; *                         decremented to obtain the resource.
; *              == 0       if the resource is not available or the event did not occur or,
; *                         if 'pevent' is a NULL pointer or,
; *                         if you didn't pass a pointer to a semaphore
; *********************************************************************************************************
; */
; 
; #if OS_SEM_ACCEPT_EN > 0
; INT16U  OSSemAccept (OS_EVENT *pevent)
; {
;    
;     INT16U     cnt;
; 
; 
; #if OS_ARG_CHK_EN > 0
;     if (pevent == (OS_EVENT *)0) {                    /* Validate 'pevent'                             */
;         return (0);
;     }
;     if (pevent->OSEventType != OS_EVENT_TYPE_SEM) {   /* Validate event block type                     */
;         return (0);
;     }
; #endif
;     OS_ENTER_CRITICAL();
;     cnt = pevent->OSEventCnt;
;     if (cnt > 0) {                                    /* See if resource is available                  */
;         pevent->OSEventCnt--;                         /* Yes, decrement semaphore and notify caller    */
;     }
;     OS_EXIT_CRITICAL();
;     return (cnt);                                     /* Return semaphore count                        */
; }
; #endif    
; 
; /*$PAGE*/
; /*
; *********************************************************************************************************
; *                                           CREATE A SEMAPHORE
; *
; * Description: This function creates a semaphore.
; *
; * Arguments  : cnt           is the initial value for the semaphore.  If the value is 0, no resource is
; *                            available (or no event has occurred).  You initialize the semaphore to a
; *                            non-zero value to specify how many resources are available (e.g. if you have
; *                            10 resources, you would initialize the semaphore to 10).
; *
; * Returns    : != (void *)0  is a pointer to the event control clock (OS_EVENT) associated with the
; *                            created semaphore
; *              == (void *)0  if no event control blocks were available
; *********************************************************************************************************
; */
; 
; OS_EVENT  *OSSemCreate (INT16U cnt)
; {
;    
;     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) {                         /* Get an event control block               */
;         pevent->OSEventType = OS_EVENT_TYPE_SEM;
;         pevent->OSEventCnt  = cnt;                         /* Set semaphore value                      */
;         pevent->OSEventPtr  = (void *)0;                   /* Unlink from ECB free list                */
;         OS_EventWaitListInit(pevent);                      /* Initialize to 'nobody waiting' on sem.   */
;     }
;     return (pevent);
; }
; 
; /*$PAGE*/
; /*
; *********************************************************************************************************
; *                                         DELETE A SEMAPHORE
; *
; * Description: This function deletes a semaphore and readies all tasks pending on the semaphore.
; *
; * Arguments  : pevent        is a pointer to the event control block associated with the desired
; *                            semaphore.
; *
; *              opt           determines delete options as follows:
; *                            opt == OS_DEL_NO_PEND   Delete semaphore ONLY if no task pending
; *                            opt == OS_DEL_ALWAYS    Deletes the semaphore 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 semaphore was deleted
; *                            OS_ERR_DEL_ISR          If you attempted to delete the semaphore from an ISR
; *                            OS_ERR_INVALID_OPT      An invalid option was specified
; *                            OS_ERR_TASK_WAITING     One or more tasks were waiting on the semaphore
; *                            OS_ERR_EVENT_TYPE       If you didn't pass a pointer to a semaphore
; *                            OS_ERR_PEVENT_NULL      If 'pevent' is a NULL pointer.
; *
; * Returns    : pevent        upon error
; *              (OS_EVENT *)0 if the semaphore was successfully deleted.
; *
; * Note(s)    : 1) This function must be used with care.  Tasks that would normally expect the presence of
; *                 the semaphore MUST check the return code of OSSemPend().
; *              2) OSSemAccept() callers will not know that the intended semaphore has been deleted unless
; *                 they check 'pevent' to see that it's a NULL pointer.
; *              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 semaphore.
; *              4) Because ALL tasks pending on the semaphore will be readied, you MUST be careful in
; *                 applications where the semaphore is used for mutual exclusion because the resource(s)
; *                 will no longer be guarded by the semaphore.
; *********************************************************************************************************
; */
; 
; #if OS_SEM_DEL_EN > 0
; OS_EVENT  *OSSemDel (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_SEM) {        /* 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 semaphore    */
;         tasks_waiting = TRUE;                              /* Yes                                      */
;     } else {
;         tasks_waiting = FALSE;                             /* No                                       */
;     }