![1. Direct Addressing Mode
PA = SBR or (SR) : EA
= : + +
CS
DS
ES
SS
BX
BP
SI
DI
8-BIT or
16-BIT Displacement
= :
CS
DS
ES
SS
Direct Address
Examples:
AND AL,[1234h]
AND CX,[0FEDBh]
AND BL,ES:[52DBh]](https://image.slidesharecdn.com/busesandaddressingmodes-230318175237-4cba98d2/85/Buses-and-Addressing-Modes-ppt-11-320.jpg)
![0
7
SEGMENT
64KB
00000h
FFFFFh
1234h
15 0
DS
15 0
0h
PA=SBA:EA=DS:1234h
19 0
Adder
EA
SBA PA
DS:0000h
DS:1234h
=
1234h
+
1. Direct Addressing Mode
Examples: AND AL,[1234h]](https://image.slidesharecdn.com/busesandaddressingmodes-230318175237-4cba98d2/85/Buses-and-Addressing-Modes-ppt-12-320.jpg)
![2. Register Indirect Addressing Mode
PA = SBR or (SR) : EA
= : + +
CS
DS
ES
SS
SI
DI
8-BIT or
16-BIT Displacement
= :
CS
DS
ES
SS
Examples:
AND AL,[SI]
AND CX,[DI]
AND BL,ES:[BX]
BX
BP
SI
DI](https://image.slidesharecdn.com/busesandaddressingmodes-230318175237-4cba98d2/85/Buses-and-Addressing-Modes-ppt-13-320.jpg)
![0
7
SEGMENT
64KB
00000h
FFFFFh
Let BX=ABCDh
15 0
ES
15 0
0h
PA=SBA:EA=ES:ABCDh
19 0
Adder
EA
SBA PA
ES:0000h
ES:ABCDh
=
ABCDh
+
2. Register Indirect Addressing Mode
EXAMPLE: AND BL,ES:[BX]](https://image.slidesharecdn.com/busesandaddressingmodes-230318175237-4cba98d2/85/Buses-and-Addressing-Modes-ppt-14-320.jpg)
![3. Based Addressing Mode
PA = SBR or (SR) : EA
= : + +
CS
DS
ES
SS
BX
BP
SI
DI
8-BIT or
16-BIT Displacement
Examples:
AND AL,[BX]+1234h
AND CX,[BP] [1234]
AND BL,ES:[BX+12FEh]
= : +
CS
DS
ES
SS
BX
BP
8-BIT or
16-BIT Displacement](https://image.slidesharecdn.com/busesandaddressingmodes-230318175237-4cba98d2/85/Buses-and-Addressing-Modes-ppt-15-320.jpg)
![0
7
SEGMENT
64KB
00000h
FFFFFh
EA=1236h
15 0
SS
15 0
0h
PA=SBA:EA=SS:1236h
19 0
Adder
EA
SBA PA
SS:0000h
=
1236h
+
3. Based Addressing Mode
EXAMPLE: AND CX,[BP] [1234h]
OFFSET=1234h
Let BP=0002h
=
+
SS:1236h
SS:1237h](https://image.slidesharecdn.com/busesandaddressingmodes-230318175237-4cba98d2/85/Buses-and-Addressing-Modes-ppt-16-320.jpg)
![4. Indexed Addressing Mode
PA = SBR or (SR) : EA
= : + +
CS
DS
ES
SS
BX
BP
SI
DI
8-BIT or
16-BIT Displacement
= : +
CS
DS
ES
SS
Examples:
AND AL,[SI] [50]
AND CX,[SI] [1234h]
AND BL,ES:[DI+12FEh]
DI
SI
8-BIT or
16-BIT Displacement](https://image.slidesharecdn.com/busesandaddressingmodes-230318175237-4cba98d2/85/Buses-and-Addressing-Modes-ppt-17-320.jpg)
![0
7
SEGMENT
64KB
00000h
FFFFFh
EA=234Ah
15 0
DS
15 0
0h
PA=SBA:EA=DS:234Ah
19 0
Adder
EA
SBA PA
DS:0000h
=
234Ah
+
4. Indexed Addressing Mode
EXAMPLE: AND CX,[SI] [2345h]
OFFSET=2345h
Let SI=0005h
=
+
DS:234Ah
DS:234Bh](https://image.slidesharecdn.com/busesandaddressingmodes-230318175237-4cba98d2/85/Buses-and-Addressing-Modes-ppt-18-320.jpg)
![5. Based Indexed Addressing Mode
PA = SBR or (SR) : EA
= : + +
CS
DS
ES
SS
BX
BP
SI
DI
8-BIT or
16-BIT Displacement
Examples:
AND AL,[SI]+[BX]+[1234h]
AND CX,[DI] [BP] [1234h]
AND BL,CS:[BX+DI+12FEh]](https://image.slidesharecdn.com/busesandaddressingmodes-230318175237-4cba98d2/85/Buses-and-Addressing-Modes-ppt-19-320.jpg)
![0
7
SEGMENT
64KB
00000h
FFFFFh
EA=0236h
15 0
DS
15 0
0h
PA=SBA:EA=DS:0236h
19 0
Adder
EA
SBA PA
DS:0000h
=
0236h
+
5. Based Indexed Addressing Mode
EXAMPLE: AND CX,[SI] [BX] [1230h]
OFFSET=0230h
Let SI=0004h
=
+
DS:0236h
DS:0237h
Let BX=0002h
+](https://image.slidesharecdn.com/busesandaddressingmodes-230318175237-4cba98d2/85/Buses-and-Addressing-Modes-ppt-20-320.jpg)
Buses and Addressing Modes.ppt
- 3. peripherals peripherals peripherals peripherals Peripherals or Memory Data BUS (16 bit) 8086 CPU Address BUS (20 bit) Control BUS
- 5. 0 7 15 8 0 7 Address BUS (20 bit) Address BUS (20 bit) Data BUS (16 bit) Data BUS (16 bit) (D8-D15) (D0-D7) 1MB 512KB 512KB Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5
- 8. OFFSET VALUE 15 0 Effective Address EA SEGMENT REGISTER 15 0 Segment Base Register SBA 0000 20-BIT 19 0 Physical Memory Address PA Adder
- 9. 0 7 SEGMENT 64KB 00000h FFFFFh 0022h 15 0 1234h 15 0 0h SBA+EA=12340+0022=12362 19 0 Adder EA SBA PA 12340h 12362h = 22 +
- 10. PA = SBR or (SR) : EA = : + + The Operand resides in an internal Register. Examples: AND AL,DH AND BX,CX The Operand is a part of the Instruction. Examples: AND AL,80h AND 0800h,BX Direct Add. Register indirect Add. Based Add. Indexed Add. Based Indexed Add. CS DS ES SS BX BP SI DI 8-BIT or 16-BIT Displacement It is a method for specifying an Operand
- 11. 1. Direct Addressing Mode PA = SBR or (SR) : EA = : + + CS DS ES SS BX BP SI DI 8-BIT or 16-BIT Displacement = : CS DS ES SS Direct Address Examples: AND AL,[1234h] AND CX,[0FEDBh] AND BL,ES:[52DBh]
- 12. 0 7 SEGMENT 64KB 00000h FFFFFh 1234h 15 0 DS 15 0 0h PA=SBA:EA=DS:1234h 19 0 Adder EA SBA PA DS:0000h DS:1234h = 1234h + 1. Direct Addressing Mode Examples: AND AL,[1234h]
- 13. 2. Register Indirect Addressing Mode PA = SBR or (SR) : EA = : + + CS DS ES SS SI DI 8-BIT or 16-BIT Displacement = : CS DS ES SS Examples: AND AL,[SI] AND CX,[DI] AND BL,ES:[BX] BX BP SI DI
- 14. 0 7 SEGMENT 64KB 00000h FFFFFh Let BX=ABCDh 15 0 ES 15 0 0h PA=SBA:EA=ES:ABCDh 19 0 Adder EA SBA PA ES:0000h ES:ABCDh = ABCDh + 2. Register Indirect Addressing Mode EXAMPLE: AND BL,ES:[BX]
- 15. 3. Based Addressing Mode PA = SBR or (SR) : EA = : + + CS DS ES SS BX BP SI DI 8-BIT or 16-BIT Displacement Examples: AND AL,[BX]+1234h AND CX,[BP] [1234] AND BL,ES:[BX+12FEh] = : + CS DS ES SS BX BP 8-BIT or 16-BIT Displacement
- 16. 0 7 SEGMENT 64KB 00000h FFFFFh EA=1236h 15 0 SS 15 0 0h PA=SBA:EA=SS:1236h 19 0 Adder EA SBA PA SS:0000h = 1236h + 3. Based Addressing Mode EXAMPLE: AND CX,[BP] [1234h] OFFSET=1234h Let BP=0002h = + SS:1236h SS:1237h
- 17. 4. Indexed Addressing Mode PA = SBR or (SR) : EA = : + + CS DS ES SS BX BP SI DI 8-BIT or 16-BIT Displacement = : + CS DS ES SS Examples: AND AL,[SI] [50] AND CX,[SI] [1234h] AND BL,ES:[DI+12FEh] DI SI 8-BIT or 16-BIT Displacement
- 18. 0 7 SEGMENT 64KB 00000h FFFFFh EA=234Ah 15 0 DS 15 0 0h PA=SBA:EA=DS:234Ah 19 0 Adder EA SBA PA DS:0000h = 234Ah + 4. Indexed Addressing Mode EXAMPLE: AND CX,[SI] [2345h] OFFSET=2345h Let SI=0005h = + DS:234Ah DS:234Bh
- 19. 5. Based Indexed Addressing Mode PA = SBR or (SR) : EA = : + + CS DS ES SS BX BP SI DI 8-BIT or 16-BIT Displacement Examples: AND AL,[SI]+[BX]+[1234h] AND CX,[DI] [BP] [1234h] AND BL,CS:[BX+DI+12FEh]
- 20. 0 7 SEGMENT 64KB 00000h FFFFFh EA=0236h 15 0 DS 15 0 0h PA=SBA:EA=DS:0236h 19 0 Adder EA SBA PA DS:0000h = 0236h + 5. Based Indexed Addressing Mode EXAMPLE: AND CX,[SI] [BX] [1230h] OFFSET=0230h Let SI=0004h = + DS:0236h DS:0237h Let BX=0002h +
- 21. Try to calculate the physical address for the examples and the related assignments of TEXT BOOK / chapter two.
- 23. 16 – bit 2 Bytes Lower Byte D0 –D7 Upper Byte D8 –D15 Used to transfer DATA between CPU and Memory.
- 24. 20 – bit One way BUS from CPU to Memory Addresses up to 1M Byte of Memory Generated by CPU to locate a specific Byte or Word in Memory Physical Address (PA) : Physical Byte address in Memory Effective Address (EA) : a number added to Segment Register contents and gives PA Segment Register is either CS, DS, ES or SS i.e. : PA(20-bit) = SR(16-bit) + EA(16-bit)
- 25. Digital signals generated either by CPU or by other Supporting ICs They manages the whole CPU operations Some of them called Control signals, the others called Status signals Control signals direction is from CPU to Memory and other Supporting ICs. Status signals direction is from Supporting ICs to CPU.