8085:branching and logical instruction

GOVERNMENT ENGINEERING
COLLEGE GANDHINAGAR
SUB:- Microprocessor and Interfacing (2140304)
TOPIC:- 8085:branching & logical instruction
BY,
NEMISH V. BHOJANI 150130103017
BODAR BHAVIN A. 150130103018
DEVAL PURAN 150130103019
BIOMEDICAL DEPARTMENT
18085:branching & logical instruction

28085:branching & logical instruction
8085:branching instruction

8085:branching & logical instruction 3
Unconditional Branch Instructions :
In Unconditional control transfer instructions, the
execution control is transferred to the specified
location independent of any status or condition.
The CS and IP are unconditionally modified to the
new CS and IP.

CALL : Unconditional Call
This instruction is used to call a Subroutine (Procedure) from a main
program. Address of procedure may be specified directly or indirectly.
There are two types of procedure depending upon whether it is
available in the same segment or in another segment.
1> Near CALL
i.e., ±32K displacement.
2> For CALL
i.e., anywhere outside the segment.
On execution this instruction stores the incremented IP & CS onto the
stack and loads the CS & IP registers with segment and offset
addresses of the procedure to be called.

RET: Return from the Procedure.
At the end of the procedure, the RET instruction must be
executed. When it is executed, the previously stored
content of IP and CS along with Flags are retrieved into the
CS, IP and Flag registers from the stack and execution of
the main program continues further.

JMP: Unconditional Jump
This instruction unconditionally transfers the
control of execution to the specified address
using an 8-bit or 16-bit displacement. No Flags
are affected by this instruction.

IRET: Return from ISR
When it is executed, the values of IP, CS and Flags
are retrieved from the stack to continue the
execution of the main program.

LOOP : LOOP Unconditionally
This instruction executes the part of the program
from the Label or address specified in the instruction
upto the LOOP instruction CX number of times. At
each iteration, CX is decremented automatically and
JUMP IF NOT ZERO structure.
Example: MOV CX, 0004H
MOV BX, 7526H
Label 1 MOV AX, CODE
OR BX, AX
LOOP Label 1

Conditional Branch Instructions :
When this instruction is executed, execution control is
transferred to the address specified relatively in the
instruction, provided the condition implicit in the Opcode is
satisfied. Otherwise execution continues sequentially.

10
Jx

8085:logical instruction

• PSW (Program Status word)
• - Flag unaffected
• * affected
• 0 reset
• 1 set
• S Sign (Bit 7)
• Z Zero (Bit 6)
• AC Auxiliary Carry (Bit 4)
• P Parity (Bit 2)
• CY Carry (Bit 0)

8085:branching and logical instruction

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