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

Program accept decimal number and convert it into given base, Q Develop a p...

Q Develop a program that accepts decimal number and converts it into given base. Fractional numbers are allowed and negative numbers are not allowed. Also check that entered number

Explain vector-scalar instructions, Vector-Scalar Instructions In this ...

Vector-Scalar Instructions In this category, when combination of vector and scalar are fetched and stored in vector register. These instructions are referred with the subsequen

What are the requirements of the user, This step of systems examination is ...

This step of systems examination is one of the most difficult. In this stage systems specifications are identified by asking what, who, when, where and how. A few questions address

What is message passing libraries, Q. What is Message Passing Libraries? ...

Q. What is Message Passing Libraries? In this part we will consider about message passing libraries. Traditionally a range of message passing libraries have been available ever

What is a binary tree, What is a binary tree? A binary tree 'T' is desc...

What is a binary tree? A binary tree 'T' is described as A finite set of elements, known as nodes, such that: either (i) or (ii) happens: (i) T is empty (known as the 'nu

Target_parent, TARGET = "_parent" "_parent" is used in a situation whe...

TARGET = "_parent" "_parent" is used in a situation where a frameset file is nested inside another frameset file. A link in one of the inner frameset documents that uses "_par

Advantages and disadvantages of public-key cryptography, Advantages and Dis...

Advantages and Disadvantages of Public-key cryptography Advantages (i) Enhanced security and convenience  (ii) Electronic records may be authenticated by affixing

Determine about selective set- logic micro operations, Selective set Th...

Selective set The selective-set operation sets to 1 bits in register A where there can corresponding 1's  in  register  B.  It  does  not  affect  bit  positions  which  have

Webforms application and to an mvc application, What is the difference amon...

What is the difference among adding routes, to a webforms application and to an mvc application? Ans) To add routes to a webforms application, we use MapPageRoute() process of

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