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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,145 @@ | ||
| /* 内存管理 */ | ||
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| #include "bootpack.h" | ||
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| #define EFLAGS_AC_BIT 0x00040000 | ||
| #define CR0_CACHE_DISABLE 0x60000000 | ||
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| unsigned int memtest(unsigned int start, unsigned int end) | ||
| { | ||
| char flg486 = 0; | ||
| unsigned int eflg, cr0, i; | ||
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| /* 确认CPU是386还是486以上的 */ | ||
| eflg = io_load_eflags(); | ||
| eflg |= EFLAGS_AC_BIT; /* AC-bit = 1 */ | ||
| io_store_eflags(eflg); | ||
| eflg = io_load_eflags(); | ||
| if ((eflg & EFLAGS_AC_BIT) != 0) { | ||
| /* 如果是386，即使设定AC=1，AC的值还会自动回到0 */ | ||
| flg486 = 1; | ||
| } | ||
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| eflg &= ~EFLAGS_AC_BIT; /* AC-bit = 0 */ | ||
| io_store_eflags(eflg); | ||
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| if (flg486 != 0) { | ||
| cr0 = load_cr0(); | ||
| cr0 |= CR0_CACHE_DISABLE; /* 禁止缓存 */ | ||
| store_cr0(cr0); | ||
| } | ||
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| i = memtest_sub(start, end); | ||
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| if (flg486 != 0) { | ||
| cr0 = load_cr0(); | ||
| cr0 &= ~CR0_CACHE_DISABLE; /* 允许缓存 */ | ||
| store_cr0(cr0); | ||
| } | ||
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| return i; | ||
| } | ||
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| 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; | ||
| } | ||
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| 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; | ||
| } | ||
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| 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 */ | ||
| } | ||
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| 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 */ | ||
| } |