直接上代码, 能看懂就理解了

记录一下

#include <windows.h>

#include <stdio.h>



BYTE GDT[6]={0};

DWORD dwH2GValue;



void __declspec(naked) GetRegister()

{

	__asm{

		pushad

		pushfd

			

			mov eax,0x8003f00c	//读取高2G内存

			mov ebx,[eax]

			mov dwH2GValue,ebx

			sgdt GDT;	//读取GDT



		popfd

		popad



		retf	//注意返回，不能是ret

	}

}





void PrintRegister()

{

		DWORD GDT_ADDR = *(PDWORD)(&GDT[2]);

		WORD GDT_LIMIT = *(PWORD)(&GDT[0]);



		printf("%x %x %x \n",dwH2GValue,GDT_ADDR,GDT_LIMIT);

}



int main(int argc, char* argv[])

{

	__asm

	{

		mov ebx,ebx

		mov ebx,ebx

	}



	char buff[6];

	

	*(DWORD*)&buff[0] = 0x12345678;

	*(WORD*)&buff[4] = 0x48;



	__asm

	{

		call fword ptr[buff]

	}



	PrintRegister();

	getchar();



	return 0;

	//return 0;

}