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Participant
3,749 Views
Registered: ‎02-22-2011

fraction arithmetic

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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Visitor
4,004 Views
Registered: ‎11-18-2008

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
Historian
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.
Visitor
4,005 Views
Registered: ‎11-18-2008

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.