Branching Group Instruction
The branching instruction instructs the processor to go to a different memory location and the microprocessor continues excluding machine code from the new location.
The branching instructions are the most powerful instructions because they allow the microprocessor to change the sequence of program either unconditionally or under certain test condition. The branching instructions are divided into following 3 groups:
a. JUMP instruction
b. CALL and RET instruction
c. RESTART instruction
The jump instruction specifies the memory location explicitly. They are 3 bytes instruction.
Jump instruction categories into unconditional and conditional.
1. Unconditional Jump: 8085 includes unconditional JUMP instruction loop without depending any types of conditions.
JMP 16-bit address
e.g. JMP 4000H
Memory location can also be specified with a label or name
2. Conditional Jump: The conditional JUMP instructions allow the microprocessor to make decision based on certain condition indicated by the flag. After logical and arithmetic operations flag are set or reset to reflect condition.
The four flags namely CY, P, Z and S are used by JUMP instructions.
MNEMONICS
|
DESCRIPTIONS
|
JC
16 bit address
|
Jump
on carry (CY=1)
|
JNC
16-bit address
|
Jump
on no carry (CY=0)
|
JZ
16-bit address
|
Jump
on zero (Z=1)
|
JNZ
16-bit address
|
Jump
on no zero (Z=0)
|
JP
16-bit address
|
Jump
on plus (S=0)
|
JM
16-bit address
|
Jump
on minus (S=1)
|
JPE
16-bit address
|
Jump
on parity even (P=1)
|
JPO
16-bit address
|
Jump
on parity odd (P=0)
|
No comments:
Post a Comment