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

Estimate the size of the state space, 1. The missionaries and cannibals pro...

1. The missionaries and cannibals problem. Three missionaries and three cannibals are on the left river bank, with a boat that can hold one or two people. If on either side of the

Software engineering - layered technology, S oftware Engineering - Layered...

S oftware Engineering - Layered Technology Although various authors have developed personal definitions of software engineering, a definition given by Fritz Bauer at the semin

Terms in propositional model, Terms in Propositional model: There in f...

Terms in Propositional model: There in first-order logic allows us to talking about properties of objects that the first job for our model (Δ, Θ) is to assign a meaning to the

Define terms setup time and hold time violation, Define setup time and hold...

Define setup time and hold time, what will occur when there is setup time and hold tine violation, how to overcome it? For Synchronous flip-flops, we have particular requiremen

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 are the objectives of usb, What are the objectives of USB? a) Simp...

What are the objectives of USB? a) Simple b) Low cost c) Easy to use d) Supports wide range of data transfer characteristics e) Plug and play mode of operation

Complicated question, Hi I need a help in this question : A telephone sw...

Hi I need a help in this question : A telephone switchboard handles ? calls on average during a rush hour, and the switchboard can at most make k connections per minute. Write a

Use verilog function to define the width of a multi-bit port, Can I use a V...

Can I use a Verilog function to define the width of a multi-bit port, wire, or reg type? Width  elements  of  ports,  wire  or  reg  declarations  require  a  constant  in  bot

Flowchart, flow chart for ''sin x'' as sum of serie

flow chart for ''sin x'' as sum of serie

Java, A string S is said to be "Super ASCII", if it contains the character ...

A string S is said to be "Super ASCII", if it contains the character frequency equal to their ascii values. String will contain only lower case alphabets (''a''-''z'') and the asci

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