tool/mbed/mbed-sdk/libraries/rtos/rtx/TARGET_CORTEX_A/rt_Memory.c

   1 /*----------------------------------------------------------------------------
   2  *      RL-ARM - RTX
   3  *----------------------------------------------------------------------------
   4  *      Name:    RT_MEMORY.C
   5  *      Purpose: Interface functions for Dynamic Memory Management System
   6  *      Rev.:    V4.60
   7  *----------------------------------------------------------------------------
   8  *
   9  * Copyright (c) 1999-2009 KEIL, 2009-2012 ARM Germany GmbH
  10  * All rights reserved.
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions are met:
  13  *  - Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  *  - Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *  - Neither the name of ARM  nor the names of its contributors may be used
  19  *    to endorse or promote products derived from this software without
  20  *    specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  23  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDERS AND CONTRIBUTORS BE
  26  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  27  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  28  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  29  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  30  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  31  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  32  * POSSIBILITY OF SUCH DAMAGE.
  33  *---------------------------------------------------------------------------*/
  34
  35 #include "rt_TypeDef.h"
  36 #include "rt_Memory.h"
  37
  38
  39 /* Functions */
  40
  41 // Initialize Dynamic Memory pool
  42 //   Parameters:
  43 //     pool:    Pointer to memory pool
  44 //     size:    Size of memory pool in bytes
  45 //   Return:    0 - OK, 1 - Error
  46
  47 int rt_init_mem (void *pool, U32 size) {
  48   MEMP *ptr;
  49
  50   if ((pool == NULL) || (size < sizeof(MEMP))) return (1);
  51
  52   ptr = (MEMP *)pool;
  53   ptr->next = (MEMP *)((U32)pool + size - sizeof(MEMP *));
  54   ptr->next->next = NULL;
  55   ptr->len = 0;
  56
  57   return (0);
  58 }
  59
  60 // Allocate Memory from Memory pool
  61 //   Parameters:
  62 //     pool:    Pointer to memory pool
  63 //     size:    Size of memory in bytes to allocate
  64 //   Return:    Pointer to allocated memory
  65
  66 void *rt_alloc_mem (void *pool, U32 size) {
  67   MEMP *p, *p_search, *p_new;
  68   U32   hole_size;
  69
  70   if ((pool == NULL) || (size == 0)) return NULL;
  71
  72   /* Add header offset to 'size' */
  73   size += sizeof(MEMP);
  74   /* Make sure that block is 4-byte aligned  */
  75   size = (size + 3) & ~3;
  76
  77   p_search = (MEMP *)pool;
  78   while (1) {
  79     hole_size  = (U32)p_search->next - (U32)p_search;
  80     hole_size -= p_search->len;
  81     /* Check if hole size is big enough */
  82     if (hole_size >= size) break;
  83     p_search = p_search->next;
  84     if (p_search->next == NULL) {
  85       /* Failed, we are at the end of the list */
  86       return NULL;
  87     }
  88   }
  89
  90   if (p_search->len == 0) {
  91     /* No block is allocated, set the Length of the first element */
  92     p_search->len = size;
  93     p = (MEMP *)(((U32)p_search) + sizeof(MEMP));
  94   } else {
  95     /* Insert new list element into the memory list */
  96     p_new       = (MEMP *)((U32)p_search + p_search->len);
  97     p_new->next = p_search->next;
  98     p_new->len  = size;
  99     p_search->next = p_new;
 100     p = (MEMP *)(((U32)p_new) + sizeof(MEMP));
 101   }
 102
 103   return (p);
 104 }
 105
 106 // Free Memory and return it to Memory pool
 107 //   Parameters:
 108 //     pool:    Pointer to memory pool
 109 //     mem:     Pointer to memory to free
 110 //   Return:    0 - OK, 1 - Error
 111
 112 int rt_free_mem (void *pool, void *mem) {
 113   MEMP *p_search, *p_prev, *p_return;
 114
 115   if ((pool == NULL) || (mem == NULL)) return (1);
 116
 117   p_return = (MEMP *)((U32)mem - sizeof(MEMP));
 118
 119   /* Set list header */
 120   p_prev = NULL;
 121   p_search = (MEMP *)pool;
 122   while (p_search != p_return) {
 123     p_prev   = p_search;
 124     p_search = p_search->next;
 125     if (p_search == NULL) {
 126       /* Valid Memory block not found */
 127       return (1);
 128     }
 129   }
 130
 131   if (p_prev == NULL) {
 132     /* First block to be released, only set length to 0 */
 133     p_search->len = 0;
 134   } else {
 135     /* Discard block from chain list */
 136     p_prev->next = p_search->next;
 137   }
 138
 139   return (0);
 140 }