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Rep:Re: [f-cpu] (!) a few noteworthy things

-----Message d'origine-----
De: Yann Guidon <whygee@f-cpu.org>
A: f-cpu@seul.org
Date: 17/06/02
Objet: Re: [f-cpu] (!) a few noteworthy things

hi,

Ben Franchuk wrote:
> Yann Guidon wrote:
<snip>
> No wait this is a RISC machine age !! You can't have 32,64?? bit
immediate
> constant in the next word! Other than stupid Immediate packing because
> of a brain dead achitecure design all data should be converted to 32
> or 64 bit  internal format upon loading and not adjusted in the
register
> bypass.

this is unrelated but you just gave me an idea for a 6th solution ("f)")
:-)

 f) avoid bypass if the size of the written register is different from
    the required operand :-)

this way, no need to make a complex bypass mux.
This is pretty easy to check, and there would be only 2 cycles
of penalty otherwise (in case of "naughty coding" practices).

oh yes, i like that :-P

>>> It look nice from a soft point of view. But it's add a dosen of
comparatrt to check the equality of the SIMD flags. e) ( at least any
version that doesn't need a read to the register bank to have the
bypass) should be more appriopriate. Is that so common to use register
as 8 bits and reuse it as 16 or 32 bits ? Does the area cost of
comparators are justified ? 
nicO

> Ben Franchuk - Dawn * 12/24 bit cpu *
WHYGEE
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