How do the registers help in instruction execution, Computer Engineering

Assignment Help:

Q. How do the registers help in instruction execution?

We will discuss this in following steps:

Step 1:

First step of instruction execution is to fetch instruction which is to be executed. To do so we need:

  • Address of 'instruction to be fetched'. Generally Program counter (PC) register stores this information.
  • Now this address is converted to physical machine address and put on address bus with help of a buffer register sometimes termed as Memory Address Register (MAR).
  • This coupled with a request from CU for reading, fetches instruction on the data bus and transfers instruction to Instruction Register (IR).
  • On the completion of fetch PC is incremented to point to subsequent instruction.

In Step 2:

  • The IR is decoded.Let's presume that Instruction Register comprises an instruction ADD Memory location B with general purpose register R1 and store result in R1 then CU will first instruct to:
  • Get data of memory location B to buffer register for data (DR) employing buffer address register (MAR) by issuing Memory read operation.
  • This data can be stored in a general purpose register if so required let's say R2
  • Now ALU will perform addition of R1 and R2 under the command of CU and the result will be put back in R1. The status of ALUoperation for illustration result in nonzero/zero, overflow/no overflow etc. is recorded in status register.
  • In the same way the other instructions are fetched and executed by using ALU and register under control of the CU.

So for explaining instruction execution we should explain the registers layout and micro-operations, ALU design and lately the control unit organization.


Related Discussions:- How do the registers help in instruction execution

Dynamic address translation - computer architecture, Dynamic address transl...

Dynamic address translation :  If, when executing an instruction, a CPU fetches an instruction located at a specific virtual address, or fetches data from a particular virtual

What happens if acknowledge() is called within a transaction, As per the JM...

As per the JMS specification, when you are in a transaction, the acknowledge Mode is ignored. If acknowledge() is known as within a transaction, it is ignored.

Design issues of multi-threaded processors, Q. Design issues of Multi-threa...

Q. Design issues of Multi-threaded processors? To accomplish the maximum processor utilization in a multithreaded architecture, the subsequent design issues should be addressed

Explain the reference count - free memory areas, Explain the Reference Coun...

Explain the Reference Count The system relates a reference count along with each memory area to point out the number of its active users. This number is incremented while a us

Auto increment mode and condition code flags, Described auto increment mode...

Described auto increment mode of addressing? Ans: Effective address of the operand is the contents of a register mention in the instruction. After finishing the accessing t

What is page stealing, What is Page stealing? Ans. Taking page frames o...

What is Page stealing? Ans. Taking page frames other working sets is called Page stealing.

Instruction per cycle in RISC, Q. Instruction per cycle in RISC? One in...

Q. Instruction per cycle in RISC? One instruction per cycle: A machine cycle is total time taken to fetch two operands from registers perform ALU operation on them and store re

JSP, What is java server pages

What is java server pages

Chemistry, application problems on electrochemical series

application problems on electrochemical series

Define coupling, Define Coupling? Coupling means the measure of interco...

Define Coupling? Coupling means the measure of interconnection between modules in a program structure. It depends on the interface problem between modules.

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