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Re: [f-cpu] the wrong way (or not?) concerning FP



Don't forget the complet FPU design from opencores.com. It seems to work
but very slow.

nicO

Michael Riepe a écrit :
> 
> On Wed, Aug 29, 2001 at 09:48:37AM +0200, Juergen Goeritz wrote:
> [...]
> > I took a look into the links you mailed. Haven't seen much
> > about a good division though. I will concentrate on the 64 bit
> > version, because 32bit is derivable from this.
> 
> I'd rather forget fdiv, for the moment.  Concentrate in Level-1 FP,
> that is: fadd, fsub, fmul, f2int, int2f, fiaprx and fsqrtiaprx (IIRC).
> 
>         fadd/fsub:
>                 use my generic adder as the core element and add an
>                 "input (de)normalizer" to it.
> 
>         fmul:
>                 basically, an unsigned multiplier (like IMU, but
>                 without all the bells and whistles like MAC and signed
>                 multiplication) for the fractional part, and a small
>                 (<= 16-bit) adder for the exponent.
> 
>         fiaprx/fsqrtiaprx:
>                 table lookup (8...16 entries) + some easy bit shuffling
> 
>         f2int/int2f:
>                 bit shuffling
> 
> Most units will also need a postprocessor for rounding, range checking
> and so on.  Shouldn't be too hard either (unless you try to be 100%
> IEEE compliant).
> 
> --
>  Michael "Tired" Riepe <Michael.Riepe@stud.uni-hannover.de>
>  "All I wanna do is have a little fun before I die"
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