Why do we need a CPU clock

-15

I'm very confused regarding the working of a cpu clock.The following questions arise in my mind-

What is the need of a clock in a cpu ?
What does synchronization mean in context of working of a cpu ?
How many instructions can be executed in one cycle ?
Can more than one instruction be executed in one cpu cycle ?

Please explain these concepts using an example, such as addition or multiplication of numbers(or any other complex one) clearly mentioning the various instructions and cycles in which they are performed.

Shivam Aggarwal

Posted 2016-01-04T09:42:30.460

Reputation: 189

3Way way to large a question. I suggest read a book on this subject (or multiple books). – Hennes – 2016-01-04T10:07:56.837

Ok but atleast answer my these small questions :) . – Shivam Aggarwal – 2016-01-04T10:09:27.447

4Vote to close as "Too broad" – duDE – 2016-01-04T10:55:06.023

Don't cross-post!! You asked essentially the same question on electronics.stackexchange.com an hour after this one. http://electronics.stackexchange.com/questions/209378/significance-of-a-cpu-clock

– tcrosley – 2016-01-04T13:02:36.407

Answers

-2

1) Basically a CPU's clock keeps everything in the CPU synchronized.

CPUs are digital and like anything else digital, they work on the principle of "on" and "off" - however, transistors take time to fully switch on or off, and if you check for the state of one while it is transitioning, you will get unpredictable results. With a clock signal, we have something that says "by this deadline, this signal should be valid." The other option is to have a second signal that says "I'm done, this signal is now valid" and I think that makes circuits much more complex.

2) Go here for the second answer Informative, Illustrative and easy to understand.

3) Go here for the third

4) The Fourth Very complicated, I say.

AND PLEASE Don't ask so long questions, that is why I gave you links.

Bhanu Kumar

Posted 2016-01-04T09:42:30.460

Reputation: 68

Thanks alot for these informative links. Now only one question I'd like to ask is "does every instruction takes the same amount of time/cycle or it also depends on the type of processor ? " – Shivam Aggarwal – 2016-01-04T12:14:30.063

@Shivamaggarwal I will give you the answer but can you please accept my answer please... If you liked it. You can edit it by opening your post and clicking the empty 'tick' icon on the left side of my answer. – Bhanu Kumar – 2016-01-04T12:33:15.883

@Shivamaggarwal I will research and give you the answer – Bhanu Kumar – 2016-01-04T12:34:57.187

I will surely once you give me the answer, or if u assure that you will surely give me the answer – Shivam Aggarwal – 2016-01-04T12:37:12.177

@Shivamaggarwal I can give you a link about this topic will that be okay? – Bhanu Kumar – 2016-01-04T12:38:18.480

Yea that will be great, and I will be waiting for the answer. – Shivam Aggarwal – 2016-01-04T12:38:58.000

@Shivamaggarwal Here is the first link.

– Bhanu Kumar – 2016-01-04T12:40:40.417

@Shivamaggarwal i will research more and give you more informations. Thank you for accepting my answer – Bhanu Kumar – 2016-01-04T12:41:34.017

Please quote the essential parts of the answer from the reference link(s), as the answer can become invalid if the linked page(s) change. – DavidPostill – 2016-01-04T13:29:19.193

I wouldn't bother. The question has been closed as too broad and shouldn't have been answered. – DavidPostill – 2016-01-04T13:32:32.930

@BhanuKumar - In the future do the research before you submit your answer. You should make an effort to do things right the first time, every time, otherwise your answers will be deleted for quality control reasons by the community. – Ramhound – 2016-01-04T18:49:36.293

What is the need of a clock in a cpu ? => CPU is a sequencial machine, one tick, one cyle, one operation/ task/ job

What does synchronization mean in context of working of a cpu ? => too many things depending on the context, rougly it ensures that information has properly propageted before the next task started

How many instructions can be executed in one cycle ? => it depends on the architecture of the CPU

Can more than one instruction be executed in one cpu cycle ? => yes but, it depends on CPU architecture

as said above, there is plenty good books about that,

Norimont

Posted 2016-01-04T09:42:30.460

Reputation: 11

Thanks for the reply :). Also "does every instruction takes the same amount of time/cycle or it also depends on the type of processor ? " – Shivam Aggarwal – 2016-01-04T12:15:35.650