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

Determine the return loss and round trip delay for echo, In a national tran...

In a national transmission system, the characteristic impedances of the 4-wire circuit and the 2-wire circuit are 1200 ? and 1000 ? respectively. The average phase velocity of the

Hard disk technology - computer architecture, Hard Disk Technology: Fi...

Hard Disk Technology: Figure of a computer hard disk drive           HDDs record data by magnetizing ferromagnetic material directionally, to represent

Quantity amounts (data type quan), A field containing quantity amounts (dat...

A field containing quantity amounts (data type QUAN) must be assigned to a reference table and a reference field. Explain? As a reference table, a system table having all the v

What are the components of i-way infrastructure, What are the components of...

What are the components of I-way Infrastructure? There are three components of the I-way infrastructure: • Consumer access equipment • Local on-Ramps • Global informat

Sound and complete, Dictator Dim wants to replace counting, in particular, ...

Dictator Dim wants to replace counting, in particular, counting the population of his land. To keep an accurate population count, Dictator Dim has instructed his secretary to add o

Interpolation algorithm, Design two matlab algorithms for enlarging the 256...

Design two matlab algorithms for enlarging the 256x256 images into 512x512 images by using bilinear and bicubic interpolations   a)  Evaluate the interpolated images with the

What are the functions of passes used in two-pass assembler, What are the f...

What are the functions of passes used in two-pass assembler? In an assembly language program, two pass translations can handle forward references early. The subsequent task

Design a xnor gate and define its work, N number of XNOR gates is linked in...

N number of XNOR gates is linked in series that is the N inputs (A0, A1, A2......) are specified in the subsequently way: A0 and A1 to first XNOR gate and A2 and O/P of First XNOR

Difference between abstract class and interface, Abstract class: Abstract c...

Abstract class: Abstract classes are the class where one or more methods are abstract but not essentially all method has to be abstract. Abstract methods are the methods, which are

Variable or compound expression - unification algorithm, Variable or compou...

Variable or compound expression - Unification algorithm: Here some things to note regarding this method are:  (i) There if really trying to match a constant to a different

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