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

Design a logic circuit, Ask questDesign a logic circuit with 4 inputs A, B,...

Ask questDesign a logic circuit with 4 inputs A, B, C & D that will produce output ‘1’ only whenever two adjacent input variables are 1’s. A & D are also to be treated as adjacent,

Explain the terms topology used in lans, Explain the terms topology used in...

Explain the terms topology used in LANs. (i) LAN topologies: This network topology is a physical schematic that shows interconnection of the several users. There are four fun

Cascade delete options, Create a relationship among Employee and Sales tabl...

Create a relationship among Employee and Sales tables using Emp No. Enforce referential integrity and select both cascade update and cascade delete options. Save the relationship.

Overview of the dreamweaver work area, Q. Overview of the Dreamweaver work ...

Q. Overview of the Dreamweaver work area? Let's start with a brief overview of the Dreamweaver work area. If you haven't already launched Dreamweaver, double-click Dreamweaver

Kirchoff''s voltage law , Kirc hoff's Voltage Law   The sum ...

Kirc hoff's Voltage Law   The sum of all the voltage drops around a closed circuit loop will add to zero  V1+(-V2)+(-V3)+(-V4)= 0

How to correctly apply the graphics patches in matlab, Open a LOCAL MACHINE...

Open a LOCAL MACHINE window and type: xhost +ashland # Add the following code sequence just before the plot command that was giving you problems: figure; set(gcf,'renderer','zbuffe

Explain how viewstate is being formed, Explain how Viewstate is being forme...

Explain how Viewstate is being formed and how it is keeps on client. The type of ViewState is System.Web.UI.StateBag, which is a dictionary that keeps name/value pairs. View St

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),

Code density and smaller faster programs, Q. Code Density and Smaller Faste...

Q. Code Density and Smaller Faster Programs? Memory was very expensive in older computer. So there was a need of less memory utilization, which is it was cost effective to have

What is the scope of public members in all classes, What is the Scope of pu...

What is the Scope of public/private/friend/protected/protected friend?    Scope of public/private/friend/protected/protected friend. Visual Basic/Visual C# Public/pub

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