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shreyassg13@gmail.com

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06-06-2011 01:33 AM

3,749 Views

Registered:
02-22-2011

Hello,

I am implementing CORDIC algorithm, in one paper they have used fixed point arithmetic, I wanted to know how to do +,-,*,/ operations in this representaion. is this the best or floating point is better?

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hwneff

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06-09-2011 04:02 PM

4,004 Views

Registered:
11-18-2008

to answer your last question about whether to do integer or floating point requires

a lot more information about what you need and how fast you need to compute

that which you need.

based, however, on your initial comment about fixed point, i would suggest you

should investigate something called "q notation" -- a convention that uses

integer-ish numbers and functions to operate on "fractions".

NB: the word "convention" -- it is just that: whether the binary digit sequence

"10000000" is 127 or 1 or 0.5 is all a matter of how one has chosen to look at it.

for starters, have a look at wikipedia:

http://en.wikipedia.org/wiki/Q_%28number_format%29

once you have the technique, then revisit those cordic papers and, if appropriate,

revisit your problem to determine the apporpriate values and ranges to be using

as you apply what you've learned.

2 Replies

bassman59

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06-06-2011 09:56 AM

3,744 Views

Registered:
02-25-2008

@shreyassg13@gmail.com wrote:

Hello,

I am implementing CORDIC algorithm, in one paper they have used fixed point arithmetic, I wanted to know how to do +,-,*,/ operations in this representaion. is this the best or floating point is better?

It depends on your application's requirements.

----------------------------Yes, I do this for a living.

hwneff

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06-09-2011 04:02 PM

4,005 Views

Registered:
11-18-2008

to answer your last question about whether to do integer or floating point requires

a lot more information about what you need and how fast you need to compute

that which you need.

based, however, on your initial comment about fixed point, i would suggest you

should investigate something called "q notation" -- a convention that uses

integer-ish numbers and functions to operate on "fractions".

NB: the word "convention" -- it is just that: whether the binary digit sequence

"10000000" is 127 or 1 or 0.5 is all a matter of how one has chosen to look at it.

for starters, have a look at wikipedia:

http://en.wikipedia.org/wiki/Q_%28number_format%29

once you have the technique, then revisit those cordic papers and, if appropriate,

revisit your problem to determine the apporpriate values and ranges to be using

as you apply what you've learned.