1、全局描述符表试验.MODEL TINY.386.STACK 100.DATAGDT DB 1000H DUP(0) ;存放读取的全局描述符表bPAE DB 0 ;操作系统是 Winxp SP2 或更新COUNT DW 0COUNT1 DW 0buffer DB 80 DUP(0)sCode DB 4,CodesData DB 4,DatasTSS32 DB 6,TSS32 s32 DB 2,32s16 DB 2,16sDPL DB 4,DPL:.CODESTART: MOV AH,00HMOV AL,03HINT 10H ;清屏LEAEDI,GDTMOV AH,0FEHMOV AL,00HIN
2、T 21H ;读 GDT SGDT EDILEAEBX,GDTMOV CX,EBXINC CX ;CX: 全局描述符表长度MOV COUNT,CXMOV EBX,EBX+2;EBX: 全局描述符表在系统中的地址 (逻辑地址)LEAEDI,GDT ;EDI: 存放读取的全局描述符表首地址MOV AH,0FEHMOV AL,01HINT 21H ;读取数据MOV CX,COUNTSHRCX,3LEAESI,GDTSTART1: MOV EAX,ESIOR EAX,ESI+4JNZ START3ADD ESI,8START2: INC COUNT1LOOP START1START17: CALL I
3、fExitJZ START17JMP EXITSTART3: LEAEDI,BUFFERMOV AX,COUNT1CALL DisplayWordMOV AL,:STOSBMOV AL, STOSBPUSH ECXMOV ECX,8START4: LODSBCALL DisplayByteMOV AL, STOSBLOOP START4MOV AL,:STOSBMOV AL, STOSBPUSH ESIMOV DL,ESI-3MOV DH,ESI-2TEST DL,10HJZ START7LEASI,sCode ;代码段TEST DL,08HJNZ START5LEASI,sData ;数据段
4、或堆栈段START5: CALL CopyStrLEASI,s32TEST DH,40HJNZ START6LEASI,s16JMP START6START7: LEASI,sTSS32 ;系统段START6: CALL CopyStrMOV AL, STOSBPOP ESIMOV AL,ESI-1 ;显示段基地址CALL DisplayByteMOV AL,ESI-4CALL DisplayByteMOV AL,ESI-5CALL DisplayByteMOV AL,ESI-6CALL DisplayByteMOV AL, STOSBTEST DH,80H ;显示结束地址JZ START8M
5、OV AL,DHAND AL,0FHCALL ToASCIISTOSBMOV AX,ESI-8CALL DisplayWordMOV AL,FSTOSBSTOSBSTOSBJMP START9START8: MOV AL,0STOSBSTOSBSTOSBMOV AL,DHAND AL,0FHCALL ToASCIISTOSBMOV AX,ESI-8CALL DisplayWordSTART9: MOV AL, STOSBPUSH ESILEASI,sDPL ;显示 DPLCALL CopyStrPOP ESIMOV AL,60HAND AL,DLROR AL,5OR AL,0STOSBMOV
6、AL, STOSBTEST DL,80HJZ START10MOV AL,PSTOSBMOV AL, STOSBJMP START11START10: MOV AL,NSTOSBMOV AL,PSTOSBSTART11: MOV AL, STOSBTEST DL,10HJZ START16TEST DL,08HJZ START14;代码段TEST DL,04HJZ START12MOV AL,CSTOSBSTART12: TEST DL,02HJZ START13MOV AL,RSTOSBJMP START13;数据段或堆栈段START14: TEST DL,04HJZ START15MOV
7、AL,ESTOSBSTART15: MOV AL,RSTOSBTEST DL,02HJZ START13MOV AL,WSTOSBJMP START13START16:;系统段MOV AL, STOSBMOV AL,0FHAND AL,DLCALL ToASCIISTOSBSTART13: MOV AL,0DHSTOSBMOV AL,0AHSTOSBMOV AL,$STOSBLEADX,bufferMOV AH,09HINT 21HPOP ECXJMP START2ToASCII PROC NEAROR AL,30HCMP AL,3AHJB ToASCII1ADD AL,07HToASCII1
8、: RETToASCII ENDPDisplayByte PROC NEARPUSH AXAND AL,0F0HROR AL,4CALL ToASCIISTOSBPOP AXAND AL,0FHCALL ToASCIISTOSBRETDisplayByte ENDPDisplayWord PROC NEARXCHG AL,AHCALL DisplayByteXCHG AL,AHCALL DisplayByteRETDisplayWord ENDPCopyStr PROC NEARLODSBXOR AH,AHMOV CX,AXREP MOVSBRETCopyStr ENDPIfExit PROC NEARPUSH AXPUSH DXMOV AH,06HMOV DL,0FFHINT 21HPOP DXPOP AXRETIfExit ENDPExit: MOV AH,4CHINT 21HEND START
