# How calculator calculate?

Discussion in 'Embedded Systems and Microcontrollers' started by RRavi, May 4, 2016.

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1. ### RRavi Thread Starter New Member

May 4, 2016
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Hello,
How calculator calculate so fast add sub multiply divide so fast?
Is there any look up table in processor of calculator?

Last edited: May 4, 2016
2. ### recklessrog Member

May 23, 2013
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It's all done with smoke and mirrors.

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3. ### RRavi Thread Starter New Member

May 4, 2016
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how he is doing?

May 4, 2016
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5. ### JWHassler Member

Sep 25, 2013
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Look up the history of the CORDIC algorithm

6. ### RRavi Thread Starter New Member

May 4, 2016
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what is it?

CORDIC (for COordinate Rotation DIgital Computer), also known as Volder's algorithm, is a simple and efficient algorithm to calculate hyperbolic and trigonometric functions, typically converging with one digit (or bit) per iteration. It is therefore also a prominent example of digit-by-digit algorithms.

7. ### WBahn Moderator

Mar 31, 2012
18,087
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As a rule they aren't that fast -- they only seem fast compared to a human. For cost and power (long battery life) the processors used by calculators tend to run pretty slow and not have a lot of sophistication. They can throw lots of cycles at a problem and still arrive at a solution fast enough that humans think it was near-instantaneous.

Now, because they ARE slow, the algorithms, such as CORDIC, that have been used have been carefully developed and optimized for performance on resource starved platforms (limited clock speed, limited memory, limited instruction set).

An adder is just what the name implies -- it's a circuit (digital in this context) circuit that takes two inputs, adds them together, and produces the result as its output. Lots of ways to implement an adder depending on what is important in a particular application -- speed, size, cost, simplicity, ....

8. ### takao21203 Distinguished Member

Apr 28, 2012
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Adder circuit is reverse of subtraction circuit. In fact electronic calculator is quite slow. normally ASIC built around some cpu core.

RRavi likes this.
9. ### WBahn Moderator

Mar 31, 2012
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Now RRitesh, what is the point of just posting the first couple of sentences from a Wikipedia article when you are asked a question. Clearly it is not because you understand what you have posted -- or at least never has been so far.

absf, jpanhalt and recklessrog like this.
10. ### jpanhalt AAC Fanatic!

Jan 18, 2008
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@WBahn Glad you said it, not me. I suspect Billy Mayo's cousin may be around too.

John

11. ### JohnInTX Moderator

Jun 26, 2012
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waitforitmodsareonit

12. ### RRavi Thread Starter New Member

May 4, 2016
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2+5 =7 ??
can we do this we digital I.C.?

13. ### odm4286 Active Member

Sep 20, 2009
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Eh I'm pretty sure its PFM

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14. ### RRavi Thread Starter New Member

May 4, 2016
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I mean in binary
00=0
01=1
10=2
11=3
.............

15. ### RRavi Thread Starter New Member

May 4, 2016
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What this mean?