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挑战内存管理

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Yourtion
2016-04-12 13:38:29 +08:00
parent 49287c1505
commit e620e5e6ed
1 changed files with 130 additions and 4 deletions
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134
09_day/bootpack.c
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@@ -3,14 +3,33 @@
#include "bootpack.h"
#include <stdio.h>
#define MEMMAN_FREES 4090 /* 大约是32KB*/
struct FREEINFO { /* 可用信息 */
unsigned int addr, size;
};
struct MEMMAN { /* 内存管理 */
int frees, maxfrees, lostsize, losts;
struct FREEINFO free[MEMMAN_FREES];
};
unsigned int memtest(unsigned int start, unsigned int end);
void memman_init(struct MEMMAN *man);
unsigned int memman_total(struct MEMMAN *man);
unsigned int memman_alloc(struct MEMMAN *man, unsigned int size);
int memman_free(struct MEMMAN *man, unsigned int addr, unsigned int size);
#define MEMMAN_ADDR 0x003c0000
void HariMain(void)
{
struct BOOTINFO *binfo = (struct BOOTINFO *) ADR_BOOTINFO;
char s[40], mcursor[256], keybuf[32], mousebuf[128];
int mx, my, i;
struct MOUSE_DEC mdec;
struct MOUSE_DEC mdec;
unsigned int memtotal;
struct MEMMAN *memman = (struct MEMMAN *) MEMMAN_ADDR;
init_gdtidt();
init_pic();
@@ -23,6 +42,10 @@ void HariMain(void)
init_keyboard();
enable_mouse(&mdec);
memtotal = memtest(0x00400000, 0xbfffffff);
memman_init(memman);
memman_free(memman, 0x00001000, 0x0009e000); /* 0x00001000 - 0x0009efff */
memman_free(memman, 0x00400000, memtotal - 0x00400000);
init_palette();
init_screen8(binfo->vram, binfo->scrnx, binfo->scrny);
@@ -33,8 +56,7 @@ void HariMain(void)
sprintf(s, "(%d, %d)", mx, my);
putfonts8_asc(binfo->vram, binfo->scrnx, 0, 0, COL8_FFFFFF, s);
i = memtest(0x00400000, 0xbfffffff) / (1024 * 1024);
sprintf(s, "memory %dMB", i);
sprintf(s, "memory %dMB free : %dKB", memtotal / (1024 * 1024), memman_total(memman) / 1024);
putfonts8_asc(binfo->vram, binfo->scrnx, 0, 32, COL8_FFFFFF, s);
for (;;) {
@@ -52,7 +74,7 @@ void HariMain(void)
i = fifo8_get(&mousefifo);
io_sti();
if (mouse_decode(&mdec, i) != 0) {
/* 3字节都凑齐了，所以把它们显示出来*/
/* 3字节都凑齐了，所以把它们显示出来*/
sprintf(s, "[lcr %4d %4d]", mdec.x, mdec.y);
if ((mdec.btn & 0x01) != 0) {
s[1] = 'L';
@@ -128,3 +150,107 @@ unsigned int memtest(unsigned int start, unsigned int end)
return i;
}
void memman_init(struct MEMMAN *man){
man->frees = 0; /* 可用信息数目 */
man->maxfrees = 0; /* 用于观察可用状况：frees的最大值 */
man->lostsize = 0; /* 释放失败的内存的大小总和 */
man->losts = 0; /* 释放失败次数 */
return;
}
unsigned int memman_total(struct MEMMAN *man)
/* 报告空余内存大小的合计 */
{
unsigned int i, t = 0;
for (i = 0; i < man->frees; i++) {
t += man->free[i].size;
}
return t;
}
unsigned int memman_alloc(struct MEMMAN *man, unsigned int size)
/* 分配 */
{
unsigned int i, a;
for (i = 0; i < man->frees; i++) {
if (man->free[i].size >= size) {
/* 找到了足够大的内存 */
a = man->free[i].addr;
man->free[i].addr += size;
man->free[i].size -= size;
if (man->free[i].size == 0) {
/* 如果free[i]变成了0，就减掉一条可用信息 */
man->frees--;
for (; i < man->frees; i++) {
man->free[i] = man->free[i + 1]; /* 代入结构体 */
}
}
return a;
}
}
return 0; /* 没有可用空间 */
}
int memman_free(struct MEMMAN *man, unsigned int addr, unsigned int size)
/* 释放 */
{
int i, j;
/* 为便于归纳内存，将free[]按照addr的顺序排列 */
/* 所以，先决定应该放在哪里 */
for (i = 0; i < man->frees; i++) {
if (man->free[i].addr > addr) {
break;
}
}
/* free[i - 1].addr < addr < free[i].addr */
if (i > 0) {
/* 前面有可用内存 */
if (man->free[i - 1].addr + man->free[i - 1].size == addr) {
/* 可以与前面的可用内存归纳到一起 */
man->free[i - 1].size += size;
if (i < man->frees) {
/* 后面也有 */
if (addr + size == man->free[i].addr) {
/* 也可以与后面的可用内存归纳到一起 */
man->free[i - 1].size += man->free[i].size;
/* man->free[i]删除 */
/* free[i]变成0后归纳到前面去 */
man->frees--;
for (; i < man->frees; i++) {
man->free[i] = man->free[i + 1]; /* 结构体赋值 */
}
}
}
return 0; /* 成功完成 */
}
}
/* 不能与前面的可用空间归纳到一起 */
if (i < man->frees) {
/* 后面还有 */
if (addr + size == man->free[i].addr) {
/* 可以与后面的内容归纳到一起 */
man->free[i].addr = addr;
man->free[i].size += size;
return 0; /* 成功完成 */
}
}
/* 既不能与前面归纳到一起，也不能与后面归纳到一起 */
if (man->frees < MEMMAN_FREES) {
/* free[i]之后的，向后移动，腾出一点可用空间 */
for (j = man->frees; j > i; j--) {
man->free[j] = man->free[j - 1];
}
man->frees++;
if (man->maxfrees < man->frees) {
man->maxfrees = man->frees; /* 更新最大值 */
}
man->free[i].addr = addr;
man->free[i].size = size;
return 0; /* 成功完成 */
}
/* 不能往后移动 */
man->losts++;
man->lostsize += size;
return -1; /* 失败 */
}