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

What are the functions of virtual file system, What are the functions of vi...

What are the functions of virtual file system (VFS)? a. It splits file-system-generic operations from their implementation explaining a clean VFS interface. It allows transpare

Example of pruning, Example of Pruning: As an example, we are assume t...

Example of Pruning: As an example, we are assume that the four choices for player one, there we are looking only two moves ahead 1 for player one and 1 for player two such as

Give the syntax of if-else statement, Give the syntax of "if-else" and "sw...

Give the syntax of "if-else" and "switch" statements and explain. if else This is used to decide whether to do something at a special point, or to decide between two courses

Real-time systems, This document is intended to help students get started w...

This document is intended to help students get started with the real-time systems (RTS) assignment. We will start on the assignment together in the laboratory. Students will then c

How call processing takes place, How call processing takes place? Fund...

How call processing takes place? Fundamental Call Procedure: Fig. demonstrates a simplification diagram exemplifying how two telephone sets (as subscribers) are interconnecte

Choosing a micro-controller, There are many different forms of micro-contro...

There are many different forms of micro-controller and a manufacturer, selecting the proper micro-controller for your application is one of the critical decisions which controls th

An example of load-store optimization using expression trees, Give LOAD-STO...

Give LOAD-STORE optimization based on expression trees for the expression (A+B)/(C-D). LOAD-STORE optimization based on expression trees for the expression (A+B)/(C-D) is given

Determine the current allocation state and granted process, An operating sy...

An operating system contains 3 resource classes. The number of resource units in these classes is 7, 7 and 10. The current resource allocation state is shown below:

Multiple instruction and multiple data stream (mimd), Multiple Instruction ...

Multiple Instruction and Multiple Data stream (MIMD) In this association, multiple control units and multiple processing elements are prepared as in MISD. But the discrepancy i

State the selective clear - logic micro operations, State the SELECTIVE CLE...

State the SELECTIVE CLEAR - logic micro operations The selective-clear operation clears to 0 bits in register A only  where there are corresponding 1's in the register B. For

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