单片机模块化程序: μCOS-II中内存管理程序使用说明

2020 年 2 月 16 日
筆記

前言

　　环形队列,链表,内存管理,这些典型的数据缓存处理方式

　　作为一个开发者是应该掌握的知识点

　　由于后面的文章涉及到了内存管理

　　故,这节先说一下内存管理

uCOSII中的内存管理源码

　　我把uCOS中的内存管理程序拷贝出来了

　　OS_MEM.C

/*  *********************************************************************************************************  *                                                uC/OS-II  *                                          The Real-Time Kernel  *                                            MEMORY MANAGEMENT  *  *                        (c) Copyright 1992-1998, Jean J. Labrosse, Plantation, FL  *                                           All Rights Reserved  *  *                                                  V2.00  *  * File : OS_MEM.C  * By   : Jean J. Labrosse  *********************************************************************************************************  */    #define  OS_MEM_C_  #include "OS_MEM.h"      //#if OS_MEM_EN && OS_MAX_MEM_PART >= 2  /*  *********************************************************************************************************  *                                         LOCAL GLOBAL VARIABLES  *********************************************************************************************************  */    static  OS_MEM      *OSMemFreeList;            /* Pointer to free list of memory partitions            */  static  OS_MEM       OSMemTbl[OS_MAX_MEM_PART];/* Storage for memory partition manager                 */  /*$PAGE*/      /*  *********************************************************************************************************  *                                        CREATE A MEMORY PARTITION  *  * Description : Create a fixed-sized memory partition that will be managed by uC/OS-II.  *  * Arguments   : addr     is the starting address of the memory partition  *  *               nblks    is the number of memory blocks to create from the partition.  *  *               blksize  is the size (in bytes) of each block in the memory partition.  *  *               err      is a pointer to a variable containing an error message which will be set by  *                        this function to either:  *  *                        OS_NO_ERR            if the memory partition has been created correctly.  *                        OS_MEM_INVALID_PART  no free partitions available  *                        OS_MEM_INVALID_BLKS  user specified an invalid number of blocks (must be >= 2)  *                        OS_MEM_INVALID_SIZE  user specified an invalid block size  *                                             (must be greater than the size of a pointer)  * Returns    : != (OS_MEM *)0  is the partition was created  *              == (OS_MEM *)0  if the partition was not created because of invalid arguments or, no  *                              free partition is available.  *********************************************************************************************************  */    OS_MEM *OSMemCreate (void *addr, INT32U nblks, INT32U blksize, INT8U *err)  {      OS_MEM  *pmem;      INT8U   *pblk;      void   **plink;      INT32U   i;      //注意这里 (INT8U *)addr 和 (INT8U)*addr 完全不同啊啊，前者 addr是指向的一个地址，而这个地址内数据不知道是什么类型的      //所以(INT8U *)说明这个地址的内容是INT8U型的，(INT8U *)addr 表示的是一个新的  addr，而后面(INT8U)*addr 表示把 *addr转换成      //一个八位的无符号整形数据        if (nblks < 2) {                                  /* Must have at least 2 blocks per partition      */          *err = OS_MEM_INVALID_BLKS;          return ((OS_MEM *)0);      }      if (blksize < sizeof(void *)) {                   /* Must contain space for at least a pointer      */          *err = OS_MEM_INVALID_SIZE;          return ((OS_MEM *)0);      }  //    OS_ENTER_CRITICAL();      pmem = OSMemFreeList;                             /* Get next free memory partition                */      if (OSMemFreeList != (OS_MEM *)0) {               /* See if pool of free partitions was empty      */          OSMemFreeList = (OS_MEM *)OSMemFreeList->OSMemFreeList;      }  //    OS_EXIT_CRITICAL();      if (pmem == (OS_MEM *)0) {                        /* See if we have a memory partition             */          *err = OS_MEM_INVALID_PART;          return ((OS_MEM *)0);      }        plink = (void **)addr;                            /* Create linked list of free memory blocks      */        pblk  = (INT8U *)addr + blksize;      for (i = 0; i < (nblks - 1); i++) {          *plink = (void *)pblk;          plink  = (void **)pblk;          pblk   = pblk + blksize;      }      *plink = (void *)0;                               /* Last memory block points to NULL              */  //    OS_ENTER_CRITICAL();      pmem->OSMemAddr     = addr;                       /* Store start address of memory partition       */      pmem->OSMemFreeList = addr;                       /* Initialize pointer to pool of free blocks     */      pmem->OSMemNFree    = nblks;                      /* Store number of free blocks in MCB            */      pmem->OSMemNBlks    = nblks;      pmem->OSMemBlkSize  = blksize;                    /* Store block size of each memory blocks        */  //    OS_EXIT_CRITICAL();      *err   = OS_NO_ERR;      return (pmem);  }  /*$PAGE*/  /*  *********************************************************************************************************  *                                          GET A MEMORY BLOCK  *  * Description : Get a memory block from a partition  *  * Arguments   : pmem    is a pointer to the memory partition control block  *  *               err     is a pointer to a variable containing an error message which will be set by this  *                       function to either:  *  *                       OS_NO_ERR           if the memory partition has been created correctly.  *                       OS_MEM_NO_FREE_BLKS if there are no more free memory blocks to allocate to caller  *  * Returns     : A pointer to a memory block if no error is detected  *               A pointer to NULL if an error is detected  *********************************************************************************************************  */    void *OSMemGet (OS_MEM *pmem, INT8U *err)  {      void    *pblk;    //    OS_ENTER_CRITICAL();      if (pmem->OSMemNFree > 0) {                       /* See if there are any free memory blocks       */          pblk                = pmem->OSMemFreeList;    /* Yes, point to next free memory block          */          pmem->OSMemFreeList = *(void **)pblk;         /*      Adjust pointer to new free list          */          pmem->OSMemNFree--;                           /*      One less memory block in this partition  */  //        OS_EXIT_CRITICAL();          *err = OS_NO_ERR;                             /*      No error                                 */          return (pblk);                                /*      Return memory block to caller            */      } else {  //        OS_EXIT_CRITICAL();          *err = OS_MEM_NO_FREE_BLKS;                   /* No,  Notify caller of empty memory partition  */          return ((void *)0);                           /*      Return NULL pointer to caller            */      }  }  /*$PAGE*/  /*  *********************************************************************************************************  *                                    INITIALIZE MEMORY PARTITION MANAGER  *  * Description : This function is called by uC/OS-II to initialize the memory partition manager.  Your  *               application MUST NOT call this function.  *  * Arguments   : none  *  * Returns     : none  *********************************************************************************************************  */    void OSMemInit (void)  {      OS_MEM  *pmem;      INT16U   i;          pmem = (OS_MEM *)&OSMemTbl[0];                    /* Point to memory control block (MCB)           */      for (i = 0; i < (OS_MAX_MEM_PART - 1); i++) {     /* Init. list of free memory partitions          */          pmem->OSMemFreeList = (void *)&OSMemTbl[i+1]; /* Chain list of free partitions                 */          pmem->OSMemAddr     = (void *)0;              /* Store start address of memory partition       */          pmem->OSMemNFree    = 0;                      /* No free blocks                                */          pmem->OSMemNBlks    = 0;                      /* No blocks                                     */          pmem->OSMemBlkSize  = 0;                      /* Zero size                                     */          pmem++;      }      OSMemTbl[OS_MAX_MEM_PART - 1].OSMemFreeList = (void *)0;      OSMemFreeList                               = (OS_MEM *)&OSMemTbl[0];  }  /*$PAGE*/  /*  *********************************************************************************************************  *                                         RELEASE A MEMORY BLOCK  *  * Description : Returns a memory block to a partition  *  * Arguments   : pmem    is a pointer to the memory partition control block  *  *               pblk    is a pointer to the memory block being released.  *  * Returns     : OS_NO_ERR         if the memory block was inserted into the partition  *               OS_MEM_FULL       if you are returning a memory block to an already FULL memory partition  *                                 (You freed more blocks than you allocated!)  *********************************************************************************************************  */    INT8U OSMemPut (OS_MEM  *pmem, void *pblk)  {  //    OS_ENTER_CRITICAL();      if (pmem->OSMemNFree >= pmem->OSMemNBlks) {  /* Make sure all blocks not already returned          */  //        OS_EXIT_CRITICAL();          return (OS_MEM_FULL);      }      *(void **)pblk      = pmem->OSMemFreeList;   /* Insert released block into free block list         */      pmem->OSMemFreeList = pblk;      pmem->OSMemNFree++;                          /* One more memory block in this partition            */  //    OS_EXIT_CRITICAL();      return (OS_NO_ERR);                          /* Notify caller that memory block was released       */  }  /*$PAGE*/  /*  *********************************************************************************************************  *                                          QUERY MEMORY PARTITION  *  * Description : This function is used to determine the number of free memory blocks and the number of  *               used memory blocks from a memory partition.  *  * Arguments   : pmem    is a pointer to the memory partition control block  *  *               pdata   is a pointer to a structure that will contain information about the memory  *                       partition.  *  * Returns     : OS_NO_ERR         Always returns no error.  *********************************************************************************************************  */    INT8U OSMemQuery (OS_MEM *pmem, OS_MEM_DATA *ppdata)  {  //    OS_ENTER_CRITICAL();      ppdata->OSAddr     = pmem->OSMemAddr;      ppdata->OSFreeList = pmem->OSMemFreeList;      ppdata->OSBlkSize  = pmem->OSMemBlkSize;      ppdata->OSNBlks    = pmem->OSMemNBlks;      ppdata->OSNFree    = pmem->OSMemNFree;  //    OS_EXIT_CRITICAL();      ppdata->OSNUsed    = ppdata->OSNBlks - ppdata->OSNFree;      return (OS_NO_ERR);  }  //#endif

　　OS_MEM.h

#ifndef OS_MEM_H_  #define OS_MEM_H_  #include "stm32f10x.h"    #ifndef OS_MEM_C_  #define OS_MEM_Cx_  extern  #else  #define OS_MEM_Cx_  #endif    #define OS_MAX_MEM_PART           4      #define OS_NO_ERR                 0  #define OS_MEM_INVALID_PART     110  #define OS_MEM_INVALID_BLKS     111  #define OS_MEM_INVALID_SIZE     112  #define OS_MEM_NO_FREE_BLKS     113  #define OS_MEM_FULL             114      typedef unsigned char  INT8U;         //无符号8位数  typedef unsigned int   INT16U;        //无符号16位数  typedef unsigned long  INT32U;        //无符号32位数      typedef struct {                       /* MEMORY CONTROL BLOCK                                         */      void   *OSMemAddr;                 /* Pointer to beginning of memory partition                     */      void   *OSMemFreeList;             /* Pointer to list of free memory blocks                        */      INT32U  OSMemBlkSize;              /* Size (in bytes) of each block of memory                      */      INT32U  OSMemNBlks;                /* Total number of blocks in this partition                     */      INT32U  OSMemNFree;                /* Number of memory blocks remaining in this partition          */  } OS_MEM;      typedef struct {      void   *OSAddr;                    /* Pointer to the beginning address of the memory partition     */      void   *OSFreeList;                /* Pointer to the beginning of the free list of memory blocks   */      INT32U  OSBlkSize;                 /* Size (in bytes) of each memory block                         */      INT32U  OSNBlks;                   /* Total number of blocks in the partition                      */      INT32U  OSNFree;                   /* Number of memory blocks free                                 */      INT32U  OSNUsed;                   /* Number of memory blocks used                                 */  } OS_MEM_DATA;      OS_MEM *OSMemCreate (void *addr, INT32U nblks, INT32U blksize, INT8U *err);  void *OSMemGet (OS_MEM *pmem, INT8U *err);  void OSMemInit (void);  INT8U OSMemPut (OS_MEM  *pmem, void *pblk);  INT8U OSMemQuery (OS_MEM *pmem, OS_MEM_DATA *ppdata);        #endif