backup/30dayMakeOS
1
0
Fork 1
mirror of https://github.com/yourtion/30dayMakeOS.git synced 2026-02-02 17:49:01 +08:00
Code Issues Packages Projects Releases Wiki Activity

内存容量检查（2）

Browse Source
This commit is contained in:
Yourtion
2016-04-12 11:22:46 +08:00
parent 1b0cdedaf0
commit 49287c1505
2 changed files with 34 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
09_day/bootpack.c
View File

@@ -4,7 +4,6 @@
#include <stdio.h>
unsigned int memtest(unsigned int start, unsigned int end);
unsigned int memtest_sub(unsigned int start, unsigned int end);
void HariMain(void)
{
@@ -129,28 +128,3 @@ unsigned int memtest(unsigned int start, unsigned int end)
return i;
}
unsigned int memtest_sub(unsigned int start, unsigned int end)
{
unsigned int i, *p, old, pat0 = 0xaa55aa55, pat1 = 0x55aa55aa;
for (i = start; i <= end; i += 0x1000) {
p = (unsigned int *) (i + 0xffc);
old = *p; /* 先记住修改前的值 */
*p = pat0; /* 试写 */
*p ^= 0xffffffff; /* 反转 */
if (*p != pat1) {
/* 检查反转结果 */
not_memory:
*p = old;
break;
}
*p ^= 0xffffffff; /* 再次反转 */
if (*p != pat0) {
/* 检查值是否恢复 */
goto not_memory;
}
*p = old; /* 恢复为修改前的值 */
}
return i;
}

34
09_day/naskfunc.nas
View File

@@ -13,6 +13,7 @@
GLOBAL _load_gdtr, _load_idtr
GLOBAL _load_cr0, _store_cr0
GLOBAL _asm_inthandler21, _asm_inthandler27, _asm_inthandler2c
GLOBAL _memtest_sub
EXTERN _inthandler21, _inthandler27, _inthandler2c
[SECTION .text]
@@ -148,3 +149,36 @@ _asm_inthandler2c:
POP DS
POP ES
IRETD
_memtest_sub: ; unsigned int memtest_sub(unsigned int start, unsigned int end)
PUSH EDI ; （由于还要使用EBX, ESI, EDI）
PUSH ESI
PUSH EBX
MOV ESI,0xaa55aa55 ; pat0 = 0xaa55aa55;
MOV EDI,0x55aa55aa ; pat1 = 0x55aa55aa;
MOV EAX,[ESP+12+4] ; i = start;
mts_loop:
MOV EBX,EAX
ADD EBX,0xffc ; p = i + 0xffc;
MOV EDX,[EBX] ; old = *p;
MOV [EBX],ESI ; *p = pat0;
XOR DWORD [EBX],0xffffffff ; *p ^= 0xffffffff;
CMP EDI,[EBX] ; if (*p != pat1) goto fin;
JNE mts_fin
XOR DWORD [EBX],0xffffffff ; *p ^= 0xffffffff;
CMP ESI,[EBX] ; if (*p != pat0) goto fin;
JNE mts_fin
MOV [EBX],EDX ; *p = old;
ADD EAX,0x1000 ; i += 0x1000;
CMP EAX,[ESP+12+8] ; if (i <= end) goto mts_loop;
JBE mts_loop
POP EBX
POP ESI
POP EDI
RET
mts_fin:
MOV [EBX],EDX ; *p = old;
POP EBX
POP ESI
POP EDI
RET