How are comparisons done in 8086 assembly language, Computer Engineering

Assignment Help:

Q. How are comparisons done in 8086 assembly language?

There is a compare instruction CMP. Though this instruction just sets the flags on comparing two operands (both 16 bits and 8 bits). Compare instruction just subtracts value of source from destination without storing result however setting the flag at the time of the process. Normally only 3 comparisons are more important. These are:

Result of comparison    Flag(s) affected

Destination < source    Carry flag = 1

Destination = source    Zero flag = 1

Destination > source    Carry = 0, Zero = 0

Let us look at 3 illustration which show how flags are set when numbers are compared. In illustration 1 BL is less than 10 so carry flag is set. In illustration 2 the zero flag is set since both operands are equal. In illustration 3 the destination (BX) is greater than source so both zero and carry flags are clear.

Example 1: 

 MOV BL, 02h 

 CMP BL, 10h; Carry flag = 1

Example 2:

 MOV AX, F0F0h

 MOV DX, F0F0h

 CMP AX, DX; Zero flag = 1

Example 3:

MOV BX, 200H

CMP BX, 0; Zero and Carry flags = 0


Related Discussions:- How are comparisons done in 8086 assembly language

Define the object orientation and its analysis, Object Orientation and Anal...

Object Orientation and Analysis An Object is anything that exists within the problem domain that can be recognized by data and/or behaviour. An example of an object is a bike.

Functions of an operating system, Question a) In multitasking Operatin...

Question a) In multitasking Operating Systems, there are two kinds of multitasking such as the "Preemptive Multitasking" and the "Cooperative Multitasking". Explain the two me

Addition of array elements using two processors, Q. Addition of array eleme...

Q. Addition of array elements using two processors? In this example we have to find sum of all elements of an array A of size n. We will divide n elements in 2 groups of roughl

How do i publish an xml message, Follow these steps: 1. Produce XML from...

Follow these steps: 1. Produce XML from the DOM document tree. 2. Serialize the generated DOM document to a StringWriter. 3. Call toString on the StringWriter and pass it into

Discuss the concept of segmentation, Discuss the concept of segmentation? ...

Discuss the concept of segmentation? Segmentation is method for the non contiguous storage allocation. This is different from paging as this supports user's view of his program

Describe about modem language, Q. Describe about Modem Language? Modems...

Q. Describe about Modem Language? Modems understand a set of instructions known as Hayes Command Set or AT Command Set. These commands are used to communicate with Modem. At ti

What is verilog, What is Verilog Verilog  language  is  still  rooted  ...

What is Verilog Verilog  language  is  still  rooted  in  it's  native  interpretative  mode.  Compilation  is  a means of speeding up simulation however has not changed the or

Where time synchronization is necessary, Time synchronization is necessary ...

Time synchronization is necessary in? Time synchronization is essential in TDM.

What do you understand by a file system, Problem (a) What do you mean...

Problem (a) What do you meant by a file system? (b) Mention the five categories of data for a basic file system reference model. What is the use of such a reference model

Define general purpose register architecture, Q. Define General Purpose Reg...

Q. Define General Purpose Register Architecture? General Purpose Register (GPR) Architecture: A register is a word of internal memory similar to the accumulator. GPR architec

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd