Re: [f-cpu] Re: Floating-Point

[Yann Guidon <whygee@f-cpu.org>]

hi !

Michael Riepe wrote:
> On Sun, Aug 19, 2001 at 03:23:50PM -0400, nicO wrote:
> > Just one point about SIMD FP. I think that SIMD flag should means an
> > others thing that for integer (no need for 8 bit).
> > What about 16 32 64 128(80 ?) ? 4 differents precisions, the last don't
> > need to be implemented in FC0.
> 
> The manual says:
> 
>         00      32-bit
>         01      64-bit
>         1x      unassigned
> 
> and the second one...

the two first codes are allocated, so we can use 2 other reserved sizes,
for example 80 and 128.

> On Sun, Aug 19, 2001 at 05:33:05PM -0400, nicO wrote:
> > Hello,
> >
> > I'm looking for the "usual" definition of the port of a unit :
> >
> > 3 data in,
> 
> Or less.
> 
> > 2 data out,
> 
> Or more.
> 
> > SIMD flag,
> 
> Make that `chunk size'; I use std_ulogic_vector(2 downto 0) for it.

oh btw, the SIMD flag is useful for an EU _only_ if you optimize for speed
and/or consumption. This flag is forwarded to the units but it is used mainly
for the making of the writeback mask (in the register set).

> > clk,
> > enable or start,
> > reset,
> > something for the exception ?
> >
> > If there is something to say if the outed data is correct or not ?
> 
> Currently not; the scheduler should know.  But we can add a `here is
> the result, take it or I'll throw it away in the next cycle' signal.
currently, only the IDIV has one.

> Something is missing: the lines that select the instruction to execute
> (if the unit can handle more than one instruction).

??

>  Michael "Tired" Riepe <Michael.Riepe@stud.uni-hannover.de>
WHYGEE "Gimme Doop, Joana" :-) (JBO)
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