Addressing Modes of 8085 Notes | EduRev

: Addressing Modes of 8085 Notes | EduRev

 Page 1


Gursharan Singh
Maninder Kaur
12-Dec-11
www.eazynotes.com 1
ADDRESSING MODES ADDRESSING MODES 
OF 8085 OF 8085
Gursharan Singh
mailme@gursharansingh.in
Maninder Kaur
mailme@maninderkaur.in
www.eazynotes.com
Addressing Modes of 8085 Addressing Modes of 8085
? T o perform any operation, we have to give 
the corresponding instructions to the 
microprocessor.
? In each instruction, programmer has to 
specify 3 things:
? Operation to be performed.
? Address of source of data.
? Address of destination of result.
2 12-Dec-11
Gursharan Singh
Maninder Kaur
www.eazynotes.com
Addressing Modes of 8085 Addressing Modes of 8085
? The method by which the address of 
source of data or the address of 
destination of result is given in the 
instruction is called Addressing Modes.
? The term addressing mode refers to the 
way in which the operand of the 
instruction is specified.
3 12-Dec-11
Gursharan Singh
Maninder Kaur www.eazynotes.com
T ypes of Addressing Modes T ypes of Addressing Modes
? Intel 8085 uses the following addressing 
modes:
1. Direct Addressing Mode
2. Register Addressing Mode
3. Register Indirect Addressing Mode
4. Immediate Addressing Mode
5. Implicit Addressing Mode
4 12-Dec-11
Gursharan Singh
Maninder Kaur
www.eazynotes.com
Direct Addressing Mode Direct Addressing Mode
? In this mode, the address of the operand 
is given in the instruction itself.
? LDA is the operation.
? 2500 H is the address of source.
? Accumulator is the destination.
5
LDA 2500 H Load the contents of memory 
location 2500 H in accumulator.
12-Dec-11
Gursharan Singh
Maninder Kaur www.eazynotes.com
Register Addressing Mode Register Addressing Mode
? In this mode, the operand is in general 
purpose register.
? MOV is the operation.
? B is the source of data.
? A is the destination.
6
MOV A, B Move the contents of register B to A.
12-Dec-11
Gursharan Singh
Maninder Kaur
Page 2


Gursharan Singh
Maninder Kaur
12-Dec-11
www.eazynotes.com 1
ADDRESSING MODES ADDRESSING MODES 
OF 8085 OF 8085
Gursharan Singh
mailme@gursharansingh.in
Maninder Kaur
mailme@maninderkaur.in
www.eazynotes.com
Addressing Modes of 8085 Addressing Modes of 8085
? T o perform any operation, we have to give 
the corresponding instructions to the 
microprocessor.
? In each instruction, programmer has to 
specify 3 things:
? Operation to be performed.
? Address of source of data.
? Address of destination of result.
2 12-Dec-11
Gursharan Singh
Maninder Kaur
www.eazynotes.com
Addressing Modes of 8085 Addressing Modes of 8085
? The method by which the address of 
source of data or the address of 
destination of result is given in the 
instruction is called Addressing Modes.
? The term addressing mode refers to the 
way in which the operand of the 
instruction is specified.
3 12-Dec-11
Gursharan Singh
Maninder Kaur www.eazynotes.com
T ypes of Addressing Modes T ypes of Addressing Modes
? Intel 8085 uses the following addressing 
modes:
1. Direct Addressing Mode
2. Register Addressing Mode
3. Register Indirect Addressing Mode
4. Immediate Addressing Mode
5. Implicit Addressing Mode
4 12-Dec-11
Gursharan Singh
Maninder Kaur
www.eazynotes.com
Direct Addressing Mode Direct Addressing Mode
? In this mode, the address of the operand 
is given in the instruction itself.
? LDA is the operation.
? 2500 H is the address of source.
? Accumulator is the destination.
5
LDA 2500 H Load the contents of memory 
location 2500 H in accumulator.
12-Dec-11
Gursharan Singh
Maninder Kaur www.eazynotes.com
Register Addressing Mode Register Addressing Mode
? In this mode, the operand is in general 
purpose register.
? MOV is the operation.
? B is the source of data.
? A is the destination.
6
MOV A, B Move the contents of register B to A.
12-Dec-11
Gursharan Singh
Maninder Kaur
Gursharan Singh
Maninder Kaur
12-Dec-11
www.eazynotes.com 2
www.eazynotes.com
Register Indirect Addressing Register Indirect Addressing 
Mode Mode
? In this mode, the address of operand is 
specified by a register pair.
? MOV is the operation.
? M is the memory location specified by H-
L register pair.
? A is the destination.
7
MOV A, M Move data from memory location 
specified by H-L pair to accumulator.
12-Dec-11
Gursharan Singh
Maninder Kaur www.eazynotes.com
Immediate Addressing Mode Immediate Addressing Mode
? In this mode, the operand is specified 
within the instruction itself.
? MVI is the operation.
? 05 H is the immediate data (source).
? A is the destination.
8
MVI   A, 05 H Move 05 H in accumulator.
12-Dec-11
Gursharan Singh
Maninder Kaur
www.eazynotes.com
Implicit Addressing Mode Implicit Addressing Mode
? If address of source of data as well as 
address of destination of result is fixed, then 
there is no need to give any operand along 
with the instruction.
? CMA is the operation.
? A is the source.
? A is the destination.
9
CMA Complement accumulator.
12-Dec-11
Gursharan Singh
Maninder Kaur www.eazynotes.com 10 12-Dec-11
Gursharan Singh
Maninder Kaur
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