1. JAI NARAIN VYAS UNIVERSITY
2020-2021
TOPIC: CLASSIFICATION OF 8085
INSTRUCTION
PRESENTED TO:
PRESENTED BY:
DR. S.K. SHARMA PRANAY
PURI
2. INSTRUCTION
INSTRUCTION is a command to
microprocessor to perform a given task on
specified data.
>8085 up instruction set has 74 operation codes that
result in 246 instructions .
Each instruction has 2 parts.
>OPCODE: which operation to be performed.
>OPERAND: data to be operand on.
3. OPCODE FORMAT
CODE REGISTER ADD Reg. B
000 B HERE
001 C ADD : 10000
010 D Reg. B : 000
011 E BINARY INSTRUCTION :10000
000
100 H 80H =ADD Reg., B
00 BC
O1 DE
10 HL
4.
5.
6.
7.
8.
9. 1.DATA TRANSFER OPERATION
These operations simply COPY the data from
the source to the destination.
–MOV, MVI, LDA, and STA
They transfer :
>Data between registers.
Data Byte to a register or memory location.
Data between a memory location and a register.
Data between an IO Device and the
accumulator
10. 2.ARITHMETIC OPERATIONS
>Addition(ADD, ADI):Any 8-bit number.
The contents of a register.
The contents of a memory location.
•Can be added to the contents of the accumulator and the result is stored in
the accumulator.
>Subtraction(SUB, SUI):Any 8-bit number
The contents of a register
The contents of a memory location
•Can be subtracted from the contents of the accumulator. The result is
stored in the accumulator
Complement:1’s complement of the contents of the accumulator.
CMA No operand
11. CONT.
Increment (INR) and Decrement(DCR):The
8-bit contents of any memory location or any
register can be directly incremented or
decremented by 1.
No need to disturb the contents of the
accumulator
12. 3.LOGIC OPERATIONS
These instructions perform logic operations on
the contents of the accumulator. ANA,
ANI, ORA, ORI, XRA and XRI
Source: Accumulator and An 8-bit number
The contents of a register
The contents of a memory location.
Destination : Accumulator
13. CONT.
ANA R/M >AND Accumulator With Reg./Mem.
ANI # > AND Accumulator With an 8-bit
number
ORA R/M >OR Accumulator With Reg./Mem.
ORI # >OR Accumulator With an 8-bit
number
XRA R/M >XOR Accumulator With Reg./Mem.
XRI # >XOR Accumulator With an 8-bit no.
Complement:1’s complement of the contents
of the accumulator.
CMA No operand
14. 4.BRANCH OPERATION
Branch Operations
Two types :Unconditional branch .Go to a new
location no matter what.
Conditional branch .Go to a new location if the
condition is true.
15. 1)UNCONDITIONAL BRANCH
JMP > Jump to the address specified (Go to).
CALL > Jump to the address specified but
treat it as a subroutine.
RET >Return from a subroutine.
16. 2)CONDITIONAL BRANCH
Go to new location if a specified condition is met.
JZ
Go to address specified if the Zero flag is set.
JNZ
Go to address specified if the Zero flag is not set.
JC
Go to the address specified if the Carry flag is set.
JN
Go to the address specified if the Carry flag is not set.
JP
Go to the address specified if the Sign flag is not set
JM
Go to the address specified if the Sign flag is set.
17. 5.MACHINE CONTROL
HLT :Stop executing the program.
NOP :No operation
Exactly as it says, do nothing.
Usually used for delay or to replace
instructions. .
