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

State the protected mode interrupt, State the Protected mode interrupt ...

State the Protected mode interrupt In protected mode, interrupts have exactly same assignments just like in real mode though the interrupt vector table is different.  Instead

Menu driven program with following menu, Q.  Develop a Menu driven program ...

Q.  Develop a Menu driven program with following menu: 1.  Gray code 2.  BCD 3.  Excess-3 code 4.  Exit I/P must be a valid Binary number. Fractional numbers are all

Automated reasoning - first-order logic, Automated Reasoning - first-order ...

Automated Reasoning - first-order logic: The topic known as "Automated Reasoning" in "AI"concentrates mostly on deductive reasoning, here new facts are logically deduced from

How many two-input AND and OR gates are required to realize , How many two-...

How many two-input AND and OR gates are required to realize Y=CD+EF+G ? Ans. Y=CD+EF+G No. of two i/p AND gates=2 No. of two i/p OR gates = 2 One OR gate to OR CD and EF

C, solution for oadovan string inc language

solution for oadovan string inc language

Explain the importance of search engines, Explain the importance of Search ...

Explain the importance of Search Engines The most effective way of finding information on the internet is to use a search engine. Though, it's just as easy to use these ineffic

What are the advantages of using xml over html, What are the advantages of ...

What are the advantages of using XML over HTML?  The root cause of the problem lies in HTML (Hyper Text Mark-up Language), the defacto standard for web publication. The main pr

Neural networks as perceptrons, Neural networks as perceptrons: Howeve...

Neural networks as perceptrons: However ANNs look like this in the general case:  Considered that the w, x, y and z represent real valued weights so all the edges in t

Define a macro definition consists of, A macro definition consists of ? ...

A macro definition consists of ? Ans. A macro Definition have: A macro prototype statement, one or various model statements and also Macro pre-processor statements

Difference between the physical drive and the logical drive., A physical dr...

A physical drive is drive the in which you can physically see in the computer system itself. That is the gadget itself. Logical drive is placed inside the physical drive and th

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