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-   -   Re: Representation of real numbers (http://www.velocityreviews.com/forums/t21346-re-representation-of-real-numbers.html)

Jeremy Pyle 06-27-2003 01:15 AM

Re: Representation of real numbers
 
As an add-on to this quetsion, are real numbers always synthesizable or only
certain architectures?


"Jeremy Pyle" <jeremyp@rochester.rr.com> wrote in message
news:e%HKa.33938$kQ5.33752@twister.nyroc.rr.com...
> Hey all,
>
> I'm trying to find out how I would get a hold of the representation of a
> real number. I know it's represented at a sign bit, exponent, mantissa,

but
> I'm trying to store this real number in RAM, meaning I have to pass it in

as
> a STD_LOGIC_VECTOR, so somehow I need to convert a real to a
> STD_LOGIC_VECTOR. Is there any way to do this?
>
> Also, I have to divide the real numbers so I'm trying to figure out the

best
> way to do it. Here are my two choices:
> 1. just use the division operator provided for real numbers
> 2. use the XiLinx dividor module provided in XiLinxCoreLib.
>
> If anyone could tell me the pros and cons of using one over the other that
> would be fantastic.
>
> Thanks all,
>
> Jeremy
>
>




Ken Smith 06-27-2003 09:35 PM

Re: Representation of real numbers
 
In article <0VMKa.34026$kQ5.19014@twister.nyroc.rr.com>,
Jeremy Pyle <jeremyp@rochester.rr.com> wrote:
>As an add-on to this quetsion, are real numbers always synthesizable or only
>certain architectures?


Real ALUs take up a lot of space. If you are trying to do an add in one
stroke, you have to have a normalizing array and an adder. This is a lot
of logic so some tools won't even try unless you are designing for a
really big chip.

--
--
kensmith@rahul.net forging knowledge



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