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

Illustration of a demon program, Q. Illustration of a demon program? Wh...

Q. Illustration of a demon program? When the PVM initialize it inspects the virtual machine in that it's to operate and creates a process known as PVM demon or simply pvmd on e

Weighted-average under perpetual inventory procedure, Q. Weighted-average u...

Q. Weighted-average under perpetual inventory procedure? Weighted-average under perpetual inventory procedure in perpetual inventory procedure firms calculate a new weighted-av

Define a structure, Define a structure. A structure having an ordered g...

Define a structure. A structure having an ordered group of data objects. Unlike the elements of an array, the data objects within a structure can have varied data types. Every

Describe the difference between cache and virtual memory, Question 1: (...

Question 1: (a) What do you meant by an expert system? (b) Describe benefits of the EDI. (c) Describe what you understand by: (i) File Infectors (ii) Boot Sect

What are subroutines, What are subroutines? Subroutines are program mo...

What are subroutines? Subroutines are program modules, which can be known  from other ABAP/4 programs or within the similar program.

Incorporate exception handling, Assignment (to be published later) will req...

Assignment (to be published later) will require you to extend the menu-driven application developed in Assignment 2B, to incorporate the recording details of the doctors who will b

Program, Write a program to find the area under the curve y = f(x) between ...

Write a program to find the area under the curve y = f(x) between x = a and x = b, integrate y = f(x) between the limits of a and b. The area under a curve between two points can b

Propositional truth tables, Propositional truth tables: There {X\t} is...

Propositional truth tables: There {X\t} is a substitution that replaces all occurances of variable X with a term representing an object t as:  ∀X. A is true if and only

Explain the importance of object oriented modelling, Explain the importance...

Explain the importance of Object Oriented Modelling It is important to note that wi t h the growing complexity of systems, significance of modelling techniques increases. Beca

What are the characteristics of dram, What are the characteristics of DRAM?...

What are the characteristics of DRAM? Low cost High density Refresh circuitry is needed

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