Conditional branch instruction-microprocessor, Assembly Language

Conditional branch Instruction

When these type of instructions are executed, they transfer control of execution to the address mention relatively in the instruction, provided the condition implicit in the op code is satisfied, or else, the execution continues in sequence. Here, the conditions mean the status of condition code flags. These types of instructions remain unaffected from any flag. The address has to be mention in the instruction relatively in the terms of displacement which ought to be lie within range -80H to 7FH (or -128 to 127) bytes from the address of the branch instruction. In other terms, only short jumps may be implemented by using the conditional branch instructions.  A label can represent the displacement, if it lies within the above mention range. The different 8086/8088 conditional branch instructions and their operations are listed in the following Table.

2183_conditional branch instruction.jpg


Last four instructions are utilized in the case of on signed binary number and decisions based operations, while all the remaining instructions may be utilized for unsigned binary operations.  The  terms  below  and  above  are usually  utilized for unsigned  numbers, while the terms greater and less are utilized for signed  numbers. A conditional jump instruction that does not examine status flags for condition testing, is following:

JCXZ 'Label' Transfer execution control to address 'Label', if register CX is equal to zero.

The conditional LOOP instructions are shown in following table along with their meanings. These instructions can be used for implement structures like REPEAT_UNTIL, DO_WHILE etc.

1192_cli.jpg

                                         Figure: Conditional loop instructions

The ideas regarding all these instructions will be clearer with the programming practice. This topic is intended at introducing these instructions to the readers. Of course, the examples are quoted wherever possible but the LOOP and the JUMP instructions need a sequence of instructions for explanations and will be emphasized.

 

 

Posted Date: 10/12/2012 5:14:41 AM | Location : United States







Related Discussions:- Conditional branch instruction-microprocessor, Assignment Help, Ask Question on Conditional branch instruction-microprocessor, Get Answer, Expert's Help, Conditional branch instruction-microprocessor Discussions

Write discussion on Conditional branch instruction-microprocessor
Your posts are moderated
Related Questions
Multiply two numbers by using shift and rotate instruction

GROUP : Group the Related Segments:- The directive which is used to form logical groups of segments with same purpose or type. This isused to inform the assembler to form a log

I/O interface I/O  devices such as displays and keyboards  establish  communication of computer with outside world. Devices may be interfaced in 2 ways Memory mapped I/O and I/

XOR: Logical Exclusive OR: The XOR operation is again carried out in a similar way to the AND and OR operation. The constraint over operands are also similar. The XOR operation pr

Program is written but has errors returning values from the procedure.

Declare 1 constant. This can be done just below the prototype section. Put the following divider above the constant section. ;************************ Constants ****************

General Data Registers Given figure indicate the register organization of 8086. The registers DX, CX, BX and AX are the general purpose 16-bit registers. AX is behaved as 16-bi

1. Write a program that calculates the Fibonacci series: 1, 1, 2, 3, 5, 8, 13, ….. (Except for the first two numbers in the sequence, each number is the sum of the preceding two n

Flowchart for the sequence of 8251 Whether the control, mode or sync character register is selected depends on the accessing sequence.  A flowchart of the sequencing is given i

write a program that calculates the fibonacci series: except for the first two numbers in the sequence