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184 lines (162 loc) · 4.2 KB
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/**
*************************************************************************
*
* memory.c
* 2016-02-17 by zlq
*
*------------------------------------------------------------------------
* @brief 本文件包含了关于内存管理的函数
*
* @attention
*
*
*************************************************************************
*/
#include <asm/io.h>
#include <miniOS/memory.h>
#define EFLAGS_AC_BIT 0x00040000
#define CR0_CACHE_DISABLE 0x60000000
#define MEM_FREES 4096
/**
* @brief 内存测试函数，并获取内存大小
*
* @param[in] start,开始地址
* @param[in] end,结束地址
* @return 内存容量
*/
unsigned int memtest(unsigned int start, unsigned int end)
{
char flg486 = 0;
unsigned int eflg,cr0,i;
//确认是386 or 486以上的
eflg = io_load_eflags();
eflg |= EFLAGS_AC_BIT;
io_store_eflags(eflg);
eflg = io_load_eflags();
if((eflg & EFLAGS_AC_BIT) != 0){
flg486 = 1;
}
eflg &= ~EFLAGS_AC_BIT;
io_store_eflags(eflg);
if(flg486 != 0){
cr0 = load_cr0();
cr0 |= CR0_CACHE_DISABLE;
store_cr0(cr0);
}
i = memtest_sub(start,end);
if(flg486 != 0){
cr0 = load_cr0();
cr0 &= ~CR0_CACHE_DISABLE;
store_cr0(cr0);
}
return i;
}
/**
* @brief 内存初始化
*
* @param[in] start,开始地址
* @param[in] end,结束地址
* @return 内存容量
*/
void memory_init(Memory_structure *mem)
{
mem->frees = 0;
mem->maxfrees = 0;
mem->lostsize = 0;
mem->losts = 0;
return;
}
unsigned int memory_total(Memory_structure *mem)
{
unsigned int i,total = 0;
for(i = 0; i < mem->frees; i++){
total += mem->free[i].size;
}
return total;
}
unsigned int mem_alloc(Memory_structure *mem,unsigned int size)
{
unsigned int i,addr;
for(i=0; i < mem->frees; i++){
if(mem->free[i].size > size){
addr = mem->free[i].addr;
mem->free[i].addr+=size;
mem->free[i].size -= size;
if(mem->free[i].size == 0){
mem->frees--;
for(; i<mem->frees; i++){
mem->free[i] = mem->free[i +1];
}
}
return addr;
}
}
return 0;
}
int mem_free(Memory_structure *mem, unsigned int addr, unsigned int size)
{
int i,j;
//寻找存放地址
for(i = 0; i< mem->frees;i++){
if(mem->free[i].addr > addr){
break;
}
}
/* free[i - 1].addr < addr < free[i].addr*/
if(i > 0){
//前面有可用的内存
if(mem->free[i-1].addr + mem->free[i-1].size == addr){
//可与和前面的内存合在一起
mem->free[i-1].size += size;
if(i < mem->frees){
//后面有可用的内存
if(addr + size == mem->free[i].addr){
//也可以和后面的内存结合在一起
mem->free[i - 1].size += mem->free[i].size;
mem->frees--;
for(;i<mem->frees;i++){
mem->free[i] = mem->free[i+1];
}
}
}
return 0;
}
}
if(i< mem->frees){
if(addr + size == mem->free[i].addr){
mem->free[i].addr = addr;
mem->free[i].size = size;
return 0;
}
}
if(mem->frees < MEM_FREES){
for(j = mem->frees; j > i; j--){
mem->free[j] = mem->free[j-1];
}
mem->frees++;
if(mem->maxfrees>mem->frees){
mem->maxfrees = mem->frees;
}
mem->free[i].addr = addr;
mem->free[i].size = size;
return 0;
}
//不能向后移动
mem->losts++;
mem->lostsize += size;
return -1;
}
unsigned int mem_alloc_4k(Memory_structure *mem, unsigned int size)
{
unsigned int a;
size = (size + 0xff) & 0xffffff00;
a = mem_alloc(mem,size);
return a;
}
int mem_free_4k(Memory_structure *mem, unsigned int addr, unsigned int size)
{
int i;
size = (size + 0xff) & 0xffffff00;
i = mem_free(mem,addr,size);
return i;
}