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

Explain dos function call with one illustration, Explain DOS function call ...

Explain DOS function call with one illustration DOS function call In order to use DOS function calls, always place function number into register AH and load all other re

Explain short note about molap?, Classic form of OLAP is called as MOLAP an...

Classic form of OLAP is called as MOLAP and it is often known as OLAP. Simple database structures like time period, product, location, etc are used. Functioning of each and every d

Classical approach - canonical genetic algorithm, Classical approach - Cano...

Classical approach - Canonical genetic algorithm: However returning to the classical approach, as there example, whether solving a particular problem involved finding a set of

Define google calendar, Define Google calendar Google Calendar is free,...

Define Google calendar Google Calendar is free, full featured, and easy to use. It lets the user create both personal and shared calendars, which makes it ideal for tracking bu

What is the size limitation of an access database, Size limitation does not...

Size limitation does not relate to number of records in a table within a database. Forms, reports, macros, and modules also add to database size, but is rather minimal compared to

Write a verilog code to swap contents of two registers, Write  a  verilog  ...

Write  a  verilog  code  to  swap  contents  of  two registers  with  and without  a  temporary register? With temp reg : always @ (posedge clock) begin temp=b; b

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

State about the object oriented analysis, State about the Object oriented a...

State about the Object oriented analysis Object oriented analysis (OOA) is concerned with developing software engineering specifications and requirements that expressed as a s

Target - data phase, Target abort -computer architecture: Usually, a t...

Target abort -computer architecture: Usually, a target holds DEVSEL# asserted through the final data phase. However, if a target desserts DEVSEL# before disconnecting without

Balanced trees and their operations, what is ment by avl tree n insertion n...

what is ment by avl tree n insertion n deletion ,2-3 tress insertion n deletion

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