stm32 内存管理

分块式内存管理

举例

#define MEM1 0 //内部SRAM#define MEM2 1 //外部SRAM#define MEM1_BLOCK_SIZE     32 //内存块大小 32字节#define MEM2_BLOCK_SIZE     32#define MEM1_MAX_SIZE       10 * 1024 //10K#define MEM2_MAX_SIZE       40 * 1024#define MEM1_TABLE_SIZE     MEM1_MAX_SIZE / MEM1_BLOCK_SIZE#define MEM2_TABLE_SIZE     MEM2_MAX_SIZE / MEM2_BLOCK_SIZEu8 mem1_pool_base[MEM1_MAX_SIZE];u8 mem2_pool_base[MEM2_MAX_SIZE] __attribute__((at(0x68000000)));u8 mem1_table_base[MEM1_TABLE_SIZE];u8 mem2_table_base[MEM2_TABLE_SIZE];typedef struct{    u8 block_size;    u16 table_size;    u8 *mem_pool; //内存池    u8 *mem_table; //内存管理表}malloc_t;malloc_t mal[2] = {    {MEM1_BLOCK_SIZE, MEM1_TABLE_SIZE, mem1_pool_base, mem1_table_base},    {MEM2_BLOCK_SIZE, MEM2_TABLE_SIZE, mem2_pool_base, mem2_table_base}};void *memset(void *s, u8 c, u32 n) //清0{    u32 i = 0;    u8 *p = s;    for(i = 0; i < n; i++)    {        *(p + i) = c;    }    return s;}void mem_init(u8 i){    memset(&mal[i].mem_pool, 0, sizeof(mal[i].mem_pool));    memset(&mal[i].mem_table, 0, sizeof(mal[i].mem_table)); }u32 mem_malloc(u8 i, u32 size){    u16 num = 0;    u16 tmp = 0;    int o = 0;    u16 j = 0;    num = size / mal[i].block_size; //整块数量    if(size % mal[i].block_size > 0)    {        num++;     }    for(o = mal[i].table_size - 1; o >= 0; o--)    {        if(mal[i].mem_table[o] == 0) //连续空内存块        {            tmp++;        }        else        {            tmp = 0;        }        if(tmp == num)        {            for(j = 0; j < num; j++)            {                mal[i].mem_table[o + j] = num; //标记非空块            }            return (o * mal[i].block_size); //返回偏移地址        }    }    return 0xFF;}void* malloc(u8 i, u32 size){    u32 offset;    offset = mem_malloc(i, size);    if(offset != 0xFF)    {        return (void*)((u32)mal[i].mem_pool + offset);    }    else    {        return NULL;    }}void mem_free(u8 i, u32 offset){    u16 num = 0;    u16 o = 0;    u16 j = 0;    o = offset / mal[i].block_size; //首块偏移    num = mal[i].mem_table[o];    for(j = 0; j < num; j++)    {        mal[i].mem_table[o + j] = 0; //块标记清0    }}void free(u8 i, void *addr){    u32 offset = 0;    offset = (u32)addr - (u32)mal[i].mem_pool;    mem_free(i, offset);}u8 mem_used(u8 i) //内存块使用率{    u16 used = 0;    u16 j = 0;    for(j = 0; j < mal[i].table_size; j++)    {        if(mal[i].mem_table[j] != 0)        {            used++;        }    }    return (used * 100 / mal[i].table_size);}