???????:??IP(?CS)????

1
3.3.5 ??????

• ????????
• ????
• ??????
• ???????
• ????

2
1.????

• ?????????IP(?CS)????
• ??????????????
• ???????????????

3
(1) ??????? - JMP ????????????????,???????????????
???CS?IP???,JMP????4???? ? ?????? JMP disp
??????8/16???????IP?CS????? ? ??????
JMP reg/mem reg/mem??16??????IP?CS?????
? ?????? JMP segmentoffset
??????16????16????????CS?IP? ? ?????? JMP
mem32 mem32??16????16????????CS?IP?
4
? ??????

• ??????????????????????????????????IP????
• ??? ???? ???????
• 8? -128127 JMP SHORT OPRD
• 16? -3276832767 JMP NEAR PTR OPRD
• ?JMP 0120H ????0120H
• JMP SHORT LP ??LP
• JMP NEAR PTR BBB ??BBB
• ???????,????CS??????

5

• ???????
• ??????????????????????
• ?1JMP SI
• ?(SI)1200H,??????,(IP)1200H,????????????1200H???
  ???
• ????????????????,??????IP????,??????16??????

6

• ?2JMP BXDI
• ??????
• (DS)3000H,(BX)1300H,
• (DI)1200H,(32500H)2350H
• ??????(IP)2350H
• ??????,??????????
• JMP WORD PTRBXDI
• ???????????????

7

• ???????
• ????????????????????????
• ?JMP 2000H1000H
• ???,(IP)?1000H,(CS)?2000H
• ???????????,????????????????????FAR PTR?
• ?JMP FAR PTR far_label
• ???far_label????????

8
???????

• ???????(????)???????????????
• JMP DWORD PTRSI
• ??????(DS)4000H,(SI)1212H,
• (41212H)1000H,(41214H)4A00H
• ??????(IP)1000H,(CS)4A00H
• ????4B000H????????
• ???DWORD PTR????????????

9
JMP DWORD PTR SI????
11111111
11101100
DSSI
4000
DS
1212
)
SI
41212
41212 41213 41214 41215
00
1000
IP
10
00
4A00
CS
4A
???????????
10
(2)?????? - JXX

• ?????????????????
• ??????????????????????????
• ??
• JXX label xx???????
• ????????-128127???
• ???????????p142?3-7?

11

• ? ????????????????
• JB/JC ??,?CF1,???
• JNB/JNC/JAE ?????,?CF0,???
• JP/JPE ????PF1(?),???
• JNP/JPO ????PF0(?),???
• JZ/JE ????(ZF1),???
• JNZ/JNE ?????(ZF0),???
• JS SF1,???
• JNS SF0,???
• JO OF1,???
• JNO OF0,???

12
? ???????????????

• ????????????????????????
• CMP dist,src ??
• Jxx label ????????
• ?????????
• JA ?????(distgtsrc)
• ????? CF0?ZF0
• JNA/JBE ????????(distsrc)
• ????? CF1?ZF1

13
?????????

• JG ?????(distgtsrc)
• ????? (SF?OF0)?ZF0
• JGE ????????(distsrc)
• ????? (SF?OF0)?ZF1
• JL ?????(distltsrc)
• ????? (SF?OF1)?ZF0
• JLE ????????(distsrc)
• ????? (SF?OF1)?ZF1

14

• ???CX??????????????
• JCXZ label
• ?(CX)0,????label??????

15

• ??????????????????BX?????
• MOV BX, 1234H
• MOV CH, 4 CH??????
• ROT MOV CL, 4 CL??????
• ROL BX, CL ???4????4?
• MOV AL, BL
• AND AL, 0FH ???4?
• ADD AL, 30H ???ASCII?
• CMP AL, 39H ? 9 ??
• JBE DISP ?(AL)9, ????
• ADD AL, 7 ?(AL)gt9, ??7??A-F
• DISP MOV DL, AL (DL)???
• MOV AH, 2
• INT 21H ????
• DEC CH 4???????????
• JNZ ROT ??, ??
• MOV DL, 48H H
• MOV AH, 2
• INT 21H ????H

16
2.??????

• ??????????????????
• ????????CX??
• ????????????-128127??????
• ?????????????

17

• (1)LOOP
• ??LOOP label
• ??(CX)-1?CX
• ?(CX)?0,???label???
• ??????,??LOOP??????
• ?LOOP???????????
• DEC CX
• JNZ label

18

• (2)LOOPZ (LOOPE)
• ??LOOPZ label
• ??(CX)-1?CX
• ?(CX)?0?ZF1,???label???
• ??????,??LOOP??????
• (3)LOOPNZ (LOOPNE)
• ??LOOPNZ label
• ??(CX)-1?CX
• ?(CX)?0?ZF0,???label???
• ??????,??LOOP??????

19

• ?1?1A000H???256????????1,? ????????0???????,?????
  ???1??????(?????1A000H)
• MOV AX, 1A00H
• MOV DS, AX
  1A00H?
• MOV DI, -1
• MOV CX, 256
• GOON INC DI
• DEC BYTE PTRDI
• LOOPNZ GOON
  
• HLT

20

• ?2?8000H??????1000??????? ??S,???,?????????A
  DDR?,??ADDR????0FFFFH?
• MOV DI, 8000H
• MOV CX, 1000
• MOV AL, S
• MOV ADDR, 0FFFFH
• GOON SCASB
• LOOPNZ GOON
• JNZ DONE
• DEC DI
• MOV ADDR,DI
• DONE HLT

21
3. ?????????

• ??(???)
• ?????????,?????????????
• ??
• ??????,IP(CS)??????????????????,??????????IP(CS)?
• ???????????????????
• ????,????
• ??????,?????????
• ??
• ?????,????,??????????????
• ??????
• ??????? CALL
• ??????? RET

22
(1)????CALL

• ????CALL sub sub???????
• ????????????,?????????
• ???????
• ???????????CALL?????
• ??CALL near_proc
• CALL???,????IP????,??????????????IP??
• ??????????????CALL???????????
• ?CALL 0120H ????????????

23

• ????????????????,???
• CS0102 CALL 0120H 3??
• CS0105
• ????? 0120-0105H001BH
• ??CALL 0120H?????E8 1B 00
• CS0102 E8
• CS0103 1B CALL 0120H
• CS0104 00
• CS0105

24
???????

• ??????????????????
• ??CALL mem16/reg16
• CALL???,????IP????,?????????/????????IP?
• ?
• CALL BX ??????BX??
• CALL WORD PTRSI ??????????

25
CALL WORD PTR SI??????? ??(DS) 8000H,(SI)
1200H
???
IPH IPL
81200H
81201H
???
26
???????

• ???????????????CALL?????
• ??CALL far_proc far_proc???????
• ??????
• ? CS????
• ? IP????
• ? CS????
• ? IP?????
• ?CALL 2000H1000H
• CALL TIMER TIMER????

27
???????

• ?????????????????4????????
• ??CALL mem32
• ??????
• SP?(SP)-2
• ((SP)1,(SP))?(CS) CS??
• CS?(mem322)
• SP?(SP)-2
• ((SP)1,(SP))?(IP) IP??
• IP?(mem32)
• ?CALL DWORD PTRDI
• ?????DI,DI1,DI2,DI3?????????????????,??
  ???????

28
CALL DWORD PTRDI
CALL
???
IPH IPL
DI
DI1
DI2
???
DI3
CSH CSL
?????????
29

• ?????????,(AX)? (DX)?
• CS2000H MOV AX, 2012H
• 2003H MOV CX, 200CH
• 2006H PUSH CX
• 2007H CALL 4000H
• 200AH ADD AX, BX
• 200CH ADD AX, DX
• 200EH HLT
• CS4000H MOV BX, 200AH
• POP DX
• RET

30
(2)????RET

• ??????RET????
• ????????IP????
• ??????RET????
• ????????IP?CS????
• ????????????? RET n ,??n???,???????????????????
  
• ?RET 4 ?????????4???

31
4.????

• 8086/8088 CPU???????????????????????,?????????,???
  ??????????????????????????????????
• ????????
• (1)INT n ????n???????,N0255
• (2)INTO ?????????????
• (3)IRET ?????????????

32
(1) INT n
????? n 0?255

• ??
• INT n
• ??
• n4 ??????????????????????????(???),???????
  ?????

??
0000 n4
XXH
XXH
?????????????(IP)
YYH
YYH
????
????????????(CS)
33

• INT?????
• ?FLAGS????
• ?INT????????????(??CS?IP?????)
• ?????????????CS?IP?
• INT?????IF?TF, ?????????
• INT?????????????,?INT 21H

34
INT??????
????

• INT 21H

??
IPL
SP11FA
IPH
??INT 21H???
CSL
CSH
FLAGSL
FLAGSH
SP1200
??INT 21H???
35
INT??????(?)

• ??INT 21H???, CS? IP?
• ??n21H,??n484H?
• ???,(00084H)2000H1123H
• ?? CS2000H IP1123H

00000084H
23H
0000 21H4
11H
IP
00H
20H
CS
36
(2)????INTO

• INTO??????OF,??OF1,???????4???????OF0,?????
  ??
• ??INTO???????????????????
• IMUL DX
• INTO ???,???INT 4, ??????
• MOV RESULT,AX
• MOV RESULT2,DX

37
(3)??????IRET

• ??????????????????IRET??????(CS?IP)???????????
• ??????????????????,?????????,?????IRET???IRET????
  ????
• ????????IP
• ????????CS
• ????????FLAG

38
3.3.6 ???????

• 1.??????
• ???????????
• (1)CF????
• CLC 0?CF
• STC 1?CF
• CMC CF??
• (2)DF????
• CLD 0?DF (??????????????)
• STD 1?DF (??????????????)
• (3)IF????
• CLI 0?IF (??INTR??)
• STI 1?IF (??INTR??)

39
2. ??????
(1)????HLT

• ??HLT???,CPU??????,???????????????
• ????(??IF1?????????INTR????????NMI)???????CPU??
  ?????
• HLT???????

40
(2)?????NOP

• NOP????????????,???3?????,??????????
• ????????????(???)?

41
??

• P152
• 3.3, 3.6, 3.12, 3.15