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

How can we draw a circle with gimp, Ans) The simplest way is to make a new ...

Ans) The simplest way is to make a new selection with Ellipse Select tool and stroke it (Edit -> Stroke Selection...). We welcome patches that add tools to draw geometric primitive

What do you understand by electronic funds transfer, What do you understand...

What do you understand by Electronic Funds Transfer?  Electronic Funds Transfer: It's an electronic payment method that transfers the money value from one bank account to

Explain the message passing interface, Q. Explain the Message Passing Inter...

Q. Explain the Message Passing Interface? The Message Passing Interface (MPI) is a universal benchmark for providing communication among multiple simultaneous processes on a di

What are the graphics adapters, Graphics adapters: Video card converts...

Graphics adapters: Video card converts digital output from computer into an analog video signal and transmits the signal through a cable to monitor also known as a graphics ca

Illustrate role of world wide web in field of e-commerce, Illustrate the ro...

Illustrate the role of World Wide Web into the field of e-commerce. In the 1990 year, the advent of the World Wide Web upon the Internet represented a turning point into e-com

Explain interface, What is an Interface? An interface is not a class. I...

What is an Interface? An interface is not a class. It is an entity that is explained by the word Interface. An interface has no implementation; it only has the signature or in

Salient points about addressing mode, Salient points about addressing mode ...

Salient points about addressing mode are:  This addressing mode is employed to initialise value of a variable. Benefit of this mode is that no extra memory accesses are

What is meant by hotspots, What is meant by hotspots? A Hotspot is a l...

What is meant by hotspots? A Hotspot is a list area where the mouse pointer appears as an upright hand symbol. When a user points to that area (and the hand cursor is active),

Load sharing facility resource management, The primary aims/details of Load...

The primary aims/details of Load Sharing Facility Resource Management Software(LSFRMS) are good resource utilization by routing the task to the most appropriate system and good uti

Describe type library and what is its purpose, Type libraries are files tha...

Type libraries are files that explicitly explain some or all of the contents of components. This haves information about the methods, properties, constants, and other members expos

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