Describe program control instructions, Computer Engineering

Assignment Help:

Q. Describe Program Control Instructions?

These instructions specify conditions for altering the sequence of program execution or we can say in other words that the content of PC (program counter) register.  PC points to memory location which holds the subsequent instruction to be executed. The alteration in value of PC as a result of execution of control instruction such as BRANCH or JUMP causes a break in sequential execution of instructions. The most common control instructions are as following:

JUMP and BRANCH may be unconditional or conditional. JUMP is an unconditional branch used to implement simple loops. JNE jump not equal is conditional branch instruction. The conditional branch instructions like BRP X and BRN X causes a branch to memory location X if the result of most recent operation is positive or negative correspondingly. If the condition is true PC is loaded with branch address X and next instruction is taken from X otherwise PC is not changed and the subsequent instruction is taken from location pointed by PC. Figure below displays an unconditional branch instruction and a conditional branch instruction if content of AC is zero.

MBR←0; Assign 0 to MBR register

X←2001; Assume X to be an address location 2001

READ X; Read a value from memory location 2001 into AC

BRZ 1007; Branch to location 1007 if AC is zero (Conditional branch on zero)

ADD MBR; add the content of MBR to AC and store result to AC

TRAS MBR; Transfer the contents of AC to MBR 

INC X; Increment X to point to next location 

JUMP 1001;Loop back for further processing.


Related Discussions:- Describe program control instructions

Explain non-folded network, Explain Non-Folded network Non-Folded Netw...

Explain Non-Folded network Non-Folded Network: In a switching network, every inlet/outlet connection may be utilized for inter exchange transmission. In this case, the .excha

History of e-commerce, In 1960: The purpose of e-commerce was to exchange t...

In 1960: The purpose of e-commerce was to exchange the electronic data. In 1970s: Electronic Fund Transfers or EFT was developed which considered as huge impact in the emerging

Define word length, Define word length?  Every group of n bits is refer...

Define word length?  Every group of n bits is referred to as a word of information and n is known as the word length.

Interpolation search, Interpolation Search The next task is to implemen...

Interpolation Search The next task is to implement a variable size decrease-and-conquer solution to search. See Levitin [2007] pp 190 for a detailed description of the interpol

Identify free memory areas in allocation and de-allocations, Name and expla...

Name and explain the popular techniques to identify free memory areas as a result of allocation and de-allocations in a heap. Two well-liked techniques to identify free memory

Seven segment decoder, A design for the seven segment decoder is required. ...

A design for the seven segment decoder is required. The decoder has four inputs which represent a number from 0 to 9 in binary and seven outputs which are connected to the seven

An example of the subscriber traffic in erlangs, A subscriber makes three p...

A subscriber makes three phone calls of 3 minutes, 4 minutes and 2 minutes duration in a one hour period. Calculate the subscriber traffic in erlangs, CCS and CM. Subscriber tr

Processes vs threads, One might argue that in general processes are more ?e...

One might argue that in general processes are more ?exible than threads. For one thing, they can live in two different machines, and communicate via sockets; they are easy to spawn

What is page fault, What is page fault? Its types? Page fault refers to...

What is page fault? Its types? Page fault refers to the situation of not having a page in the major memory when any process references it. There are two kinds of page fault :

Illustrate why does a tea kettle sing, Q. Illustrate why does a tea kettle ...

Q. Illustrate why does a tea kettle sing? Answer:- There is a little attachment with a hole in it which acts as a whistle. It is inserted into the spout of the kettle as w

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