Pogram Counter

Posted on 2002-03-26
Last Modified: 2012-05-04
why there is bidirectional path between "Program Counter" & "Data Bus" in micro processors of Intel Series.
As Memory address of Instruction is placed from Data Bus to Program Counter in one direction What is moved back from Program Counter to Data Bus in reverse direction.
Question by:SairaZaidi
  • 2

Accepted Solution

willinois earned 45 total points
ID: 6896449
LVL 32

Assisted Solution

jhance earned 45 total points
ID: 6896745
There must be a bi-directional path between the PC (program counter) and the data bus on Intel architecture CPUs to support instructions that:

1) Set the PC from an instruction.  Like an absolute JMP.  The data following the JMP opcode is the new PC and must be able to get from the data bus to the PC.

2) Set memory from the PC.  A good example is the CALL instruction.  CALL pushes the PC onto the STACK.  Since the stack is in memory on Intel CPUs, there must be a path from the PC to data bus.

Of course it's possible to have the PC go somewhere else BEFORE sending it to the data bus and therefore eliminate the direct PC <--> data bus path but the frequency of such instructions as noted above would make this missing path a major bottleneck.

CPU architecture designers spend a lot of time modelling things to figure out where the bottlenecks are and how to best eliminate them.

Expert Comment

ID: 8954962
No comment has been added lately, so it's time to clean up this TA.
I will leave a recommendation in the Cleanup topic area that this question is:
Accept a comment Split between willinois and jhance .
Please leave any comments here within the next seven days.
EE Cleanup Volunteer
LVL 32

Expert Comment

ID: 8955339
Do it.  This question has been hanging for > 1 year!!!

Featured Post

Use Case: Protecting a Hybrid Cloud Infrastructure

Microsoft Azure is rapidly becoming the norm in dynamic IT environments. This document describes the challenges that organizations face when protecting data in a hybrid cloud IT environment and presents a use case to demonstrate how Acronis Backup protects all data.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Docker for Windows 2016 5 75
Best RAM for a PC 4 63
Fastest SSD 10 83
Raid 0 2 61
I use more than 1 computer in my office for various reasons. Multiple keyboards and mice take up more than just extra space, they make working a little more complicated. Using one mouse and keyboard for all of my computers makes life easier. This co…
This paper addresses the security of Sennheiser DECT Contact Center and Office (CC&O) headsets. It describes the DECT security chain comprised of “Pairing”, “Per Call Authentication” and “Encryption”, which are all part of the standard DECT protocol.
This Micro Tutorial will give you a basic overview how to record your screen with Microsoft Expression Encoder. This program is still free and open for the public to download. This will be demonstrated using Microsoft Expression Encoder 4.
Two types of users will appreciate AOMEI Backupper Pro: 1 - Those with PCIe drives (and haven't found cloning software that works on them). 2 - Those who want a fast clone of their boot drive (no re-boots needed) and it can clone your drive wh…

821 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question