Arithmetic Instructions in 8085 Microprocessor

Arithmetic Instructions in 8085 Microprocessor

S.No
Instruction
Example
1.
Add register or memory to accumulator
ADD R
ADD M
ADD B
ADD M
‘Add register or memory to accumulator’ instruction set denotes:-
“The contents of the operand (memory or register) are added to the contents of the accumulator and the result is stored in the accumulator”.
2.
Add register to accumulator with carry
ADC R
ADC M
ADC B
ADC M
“Add register to accumulator with carry” instruction represents:-
The data of the operand (register or memory) and the Carry flag are summed (added) to the datas of the accumulator.
 The result is stored in the accumulator.
3.
Add immediate to accumulator
ADI 8-bit data
ADI 45H
‘Add immediate to accumulator’ instruction denotes:-
The 8-bit data (operand) is added to the data of the accumulator. The result is stored in the accumulator.
4.
Add immediate to accumulator with carry
ACI 8-bit data
ACI 45H
‘Add immediate to accumulator with carry’ instruction represents:-
The Carry flag and the 8-bit data are added to the data of the accumulator .
The result is stored in the accumulator.
5.
Add register pair to H and L registers
DAD Reg. pair
DAD H
‘Add register pair to H and L registers’ instruction represents:-
The 16-bit data of the specified register pair are added to the datas of the HL register .
 The sum is stored in the HL register.
6.
Subtract register or memory from accumulator
SUB R
SUB M
SUB B
SUB M
‘Subtract register or memory from accumulator’ instruction is used for:
The contents of the operand (memory or register ) are subtracted from the contents of the accumulator,.
The result is stored in the accumulator.
7.
Subtract source and borrow from accumulator
SBB R
SBB M
SBB B
SBB M
‘Subtract source and borrow from accumulator’ instruction represents:-
The contents of the operand (register or memory) and the Borrow (carry flag) are subtracted from the contents of the accumulator .
The result is placed in the accumulator.
8.
Subtract immediate from accumulator
SUI 8-bit data
SUI 45H
The instruction ‘Subtract immediate from accumulator’ represents:-
 The 8-bit data (operand) is subtracted from the datas of the accumulator.
The result is stored in the accumulator.
9.
Subtract immediate from accumulator with borrow
SBI 8-bit data
SBI 45H
The instruction ‘Subtract immediate from accumulator with borrow’ represents:-
 The 8-bit data (operand) and the Borrow (carry flag) are subtracted from the contents of the accumulator.
The result is stored in the accumulator.
10.
Increment register or memory by 1
INR R
INR M
INR B
INR M
The instruction ‘Increment register or memory by 1’ represents:-
 The content of the designated register or memory is incremented by 1 and the result is stored in the same place.
11.
Increment register pair by 1
INX Reg. pair
INX B
INX D
INX H


The instruction ‘Increment register pair by 1’ represents:-
The datas of the designated register pair gets incremented by 1.
The result is stored in the same place.
12.
Decrement register or memory by 1
DCR R
DCR M
DCR B
DCR M
‘Decrement register or memory by 1’ instruction represents:-
 The datas of the designated register or memory is decremented by 1 and the result is stored in the same place.
13.
Decrement register pair by 1
DCX Reg. pair
DCX B
DCX D
DCX H
‘Decrement register pair by 1:  DCX Reg. pair ‘ instruction set represents:
 The datas of the designated register pair gets decremented by 1.
 The result is stored in the same place.
14.
Decimal adjust accumulator
DAA
DAA
‘Decimal adjust accumulator’ instruction set represents:-
DAA The contents of the accumulator are changed from a binary value to two 4-bit binary coded decimal (BCD) digits.
 If AC flag is set  or the value of the low-order 4-bits in the accumulator is more than 9, the instruction adds 6 to the low-order four bits.   
 If the value of the high-order 4-bits in the accumulator is more than 9 or the Carry flag is set, the instruction adds 6 to the high-order four bits.















Sreejith Hrishikesan

Sreejith Hrishikesan is a ME post graduate and has been worked as an Assistant Professor in Electronics Department in KMP College of Engineering, Ernakulam. For Assignments and Projects, Whatsapp on 8289838099.

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