Conditional and Unconditional JUMP instructions in 8085 Microprocessor

Microprocessor8085

In 8085 Instruction set,there are a set of jump instructions, which can transfer program control to a certain memory location. So after these branching mnemonics we shall have to mention 16-bit target address of the location. These jump instructions can be divided into two categories– 

  • Unconditional jump instructions and

  • Conditional jump instructions

Under unconditional jump instructions there is only one mnemonic i.e. JUMP. But under conditional Jump instructions we are having 8 different mnemonics. We know that there are 5 flag bits in 8085 Flag register. They are S, Z,P, Cy, AC. Out of them only on AC flag bit, there is no jump instruction. But for rest 4 flag bits, we are having 8 conditional jump instructions depending upon their 1 or 0 i.e. TRUE and FALSE values respectively. Here is the list of all branching instructions in the following table – 


Mnemonics, Operand
Opcode(in HEX)
Bytes
JC Label
DA
3
JM Label
FA
3
JMP Label
C3
3
JNC Label
D2
3
JNZ Label
C2
3
JP Label
F2
3
JPE Label
EA
3
JPO Label
E2
3
JZ Label
CA
3


The following table shows the list of Branching instructions with their meanings.

Opcode
Operand
Meaning
Explanation
JMP
16-bit address
Jump unconditionally
The program sequence is transferred to the memory address given in the operand.
Opcode
Description
Flag Status
JC
Jump on Carry
CY=1
JNC
Jump on no Carry
CY=0
JP
Jump on positive
S=0
JM
Jump on minus
S=1
JZ
Jump on zero
Z=1
JNZ
Jump on no zero
Z=0
JPE
Jump on parity even
P=1
JPO
Jump on parity odd
P=0



16-bit address
Jump conditionally
The program sequence is transferred to the memory address given in the operand based on the specified flag of the PSW.


raja
Published on 27-Dec-2018 15:36:24
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