/***********************************************************************************************************                                                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**********************************************************************************************************/#ifndef  OS_MASTER_FILE#include "includes.h"#endif#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;    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 *pdata){    OS_ENTER_CRITICAL();    pdata->OSAddr     = pmem->OSMemAddr;    pdata->OSFreeList = pmem->OSMemFreeList;    pdata->OSBlkSize  = pmem->OSMemBlkSize;    pdata->OSNBlks    = pmem->OSMemNBlks;    pdata->OSNFree    = pmem->OSMemNFree;    OS_EXIT_CRITICAL();    pdata->OSNUsed    = pdata->OSNBlks - pdata->OSNFree;    return (OS_NO_ERR);                         }#endif