4G Memory Access （谁能帮我改下，能在VC6.0下编译通过）

[qq506664095]

2.4.1 程序的意义
此程序具有如下功能：

Ø 不需要在保护模式状态下就可以直接把386的4GB内存读出来；

Ø 利用此程序可直接在DOS中做物理设备的检测；

Ø 理解GDT表的对应关系后，所谓386 32位模式也就很容易理解；

Ø 在DOS下，可根据此类方法将中断向量表移到任意位置，达到反跟踪或其他等目的。

2.4.2 程序代码
程序代码如下所示。

#include <dos.h>

////////////////////////////////////////////////////////////////

// 4G Memory Access

// This Program Can Access 4G Bytes in DOS Real

//Mode,Needn't in Protection Mode It Works.

// The Program Enter 32 Bit Flat Mode a moment and

//Only Load FS a 32 Bit Flat Mode Selector,Then Return

//Real Mode.

// Used The FS Can Access All 4G Memory till It be

//reloaded.

//

///////////////////////////////////////////////////////////////



unsigned long GDT_Table[]=

{ 0, 0, //NULL - 00H

0x0000FFFF, 0x00CF9A00, //Code32 - 08H Base=0

//Limit=4G-1 Size=4G

0x0000FFFF, 0x00CF9200 //Data32 - 10H Base=0

//Limit=4G-1 Size=4G

};



//Save The IDTR before Enter Protect Mode.

unsigned char OldIDT[6]={0};



//NULL The IDTR,IDTR's Limit=0 will disable all

//Interrupts,include NMI.

unsigned char pdescr_tmp[6]={0};



#define KeyWait() {while(inportb(0x64)&2);}

void A20Enable(void)

{

KeyWait();

outportb(0x64,0xD1);

KeyWait();

outportb(0x60,0xDF); //Enable A20 with 8042.

KeyWait();

outportb(0x64,0xFF);

KeyWait();

}





void LoadFSLimit4G(void)

{

A20Enable(); //Enable A20



//**************************************

//* Disable ints & Null IDT *

//**************************************

asm {

CLI //Disable inerrupts

SIDT OldIDT //Save OLD IDTR

LIDT pdescr_tmp //Set up empty IDT.Disable any

//interrupts,

} //Include NMI.

//***************************************

//* Load GDTR *

//***************************************

asm {



//The right Code is Real,But BC++'s Linker NOT Work

//with 32-bits Code.

db 0x66 //32 bit Operation Prefix in 16 Bit DOS.

MOV CX,DS //MOV ECX,DS

db 0x66 //Get Data segment physical Address

SHL CX,4 //SHL ECX,4

MOV word ptr pdescr_tmp[0],(3*8-1)

//MOV word ptr pdescr_tmp[0],(3*8-1)

db 0x66

XOR AX,AX //XOR EAX,EAX

MOV AX,offset GDT_Table

//MOV AX,offset GDT_Table

db 0x66

ADD AX,CX //ADD EAX,ECX

MOV word ptr pdescr_tmp[2],AX

//GDTR Base high16 bits

db 0x66

SHR AX,16 //SHR EAX,16

MOV word ptr pdescr_tmp[4],AX

//GDTR Base high16 bits

LGDT pdescr_tmp //Load GDTR

}

//**************************************

//* Enter 32 bit Flat Protected Mode *

//**************************************

// Set CR0 Bit-0 to 1 Enter 32 Bit Protection

//Mode,And NOT Clear machine perform cache,It Meaning

//the after Code HAD Ready To RUN in 32 Bit Flat Mode,

//Then Load Flat Selector to FS and Description into it's

//Shadow register,After that,ShutDown Protection Mode

//And ReEnter Real Mode immediately.

// The FS holds Base=0 Size=4G Description and

//it can Work in Real Mode as same as Pretect Mode,

//untill FS be reloaded.

// In that time All the other Segment Registers are

//Not Changed,except FS.(They are ERROR Value holded in CPU).

asm {

MOV DX,0x10 //The Data32 Selector

db 0x66,0x0F,0x20,0xC0 //MOV EAX,CR0

db 0x66

MOV BX,AX //MOV EBX,EAX

OR AX,1

db 0x66,0x0F,0x22,0xC0 //MOV CR0,EAX

//Set Protection enable bit

JMP Flush

} //Clear machine perform cache.

Flush: //Now In Flat Mode,But The

//CS is Real Mode Value.

asm { //And it's attrib is 16-Bit Code

//Segment.

db 0x66

MOV AX,BX //MOV EAX,EBX

db 0x8E,0xE2 //MOV FS,DX //Load FS now

db 0x66,0x0F,0x22,0xC0

//MOV CR0,EAX

//Return Real Mode.Now FS's Base=0 Size=4G

LIDT OldIDT

//LIDT OldIDT Restore IDTR

STI //STI Enable INTR

}

}

//With FS can Access All 4G Memory Now.But if FS be reloaded

//in Real Mode It's Limit will Be Set to FFFFh(Size=64K),

//then Can not used it

// to Access 4G bytes Memory Again,Because FS is Segment:Offset

//Memory type after that.

//If Use it to Access large than 64K will generate Execption 0D.

//unsigned char ReadByte(unsigned long Address)

{

asm db 0x66

asm mov di,word ptr Address //MOV EDI,Address

asm db 0x67 //32 bit Address Prefix

asm db 0x64 //FS:

asm mov al,byte ptr [BX] //=MOV AL,FS:[EDI]

return _AL;

}

unsigned char WriteByte(unsigned long Address)

{

asm db 0x66

asm mov di,word ptr Address //MOV EDI,Address

asm db 0x67 //32 bit Address Prefix

asm db 0x64 //FS:

asm mov byte ptr [BX],al //=MOV FS:[EDI],AL

return _AL;

}

///////////////// Don't Touch Above Code /////////////

#include <stdio.h>

/////////////////////////////////////////////////////////////

//打印出Address指向的内存中的数据

///////////////////////////////////////////////////////////

void Dump4G(unsigned long Address)

{

int i;

int j;

for(i=0;i<20;i++)

{

printf("%08lX: ",(Address+i*16));

for(j=0;j<16;j++)

printf("%02X ",ReadByte(Address+i*16+j));

printf(" ");

for(j=0;j<16;j++)

{

if(ReadByte(Address+i*16+j)<0x20) printf(".");

else printf("%c",ReadByte(Address+i*16+j));

}

printf("\n");

}

}

main()

{

char KeyBuffer[256];

unsigned long Address=0;

unsigned long tmp;



LoadFSLimit4G();

printf("====Designed By Southern.1995.7.17====\n");

printf("Now you can Access The Machine All 4G Memory.\n");

printf("Input the Start Memory Physical to DUMP.\n");

printf("Press D to Cuntinue DUMP,0 to End & Quit.\n");

do {

printf("-");

gets(KeyBuffer);

sscanf(KeyBuffer,"%lX",&tmp);

if(KeyBuffer[0]=='q') break;

if(KeyBuffer[0]=='d') Address+=(20*16);

else Address=tmp;

Dump4G(Address);

}while(Address!=0);

return 0;

}

程序运行后，等用户从键盘输入一个字符。当输入“Q”字符时，整个程序将退出，当输入“D”时，将在屏幕上显示一屏内存的数据，最左边为绝对地址，其后一列显示的是以十六进制位表示的内存的数据，后一列是数据所对应的ASCII码。

我要使上面的程序能在VC6.0编译通过，要怎么改?

还有:

#define KeyWait() {while(inportb(0x64)&2);}

的inportb是做什么用的？

[mLee79]

inportb == _inp , 从一个端口读一个字节...
vc6 就表想了,跑不了的...