Re: [f-cpu] Supported Instructions

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

hi,

Juergen Goeritz wrote:
> On Sat, 6 Apr 2002, Yann Guidon wrote:
> >nico wrote:
> >> Yann Guidon a écrit :
> >> > nico wrote:
> ><snip>
> >> > >  - How to access indirectly the register set ? (to extract data)
> >> > fetch them from the CMB.
> >>
> >> So you must manipulate the instruction world and then manipulate the
> >> CMB. But it will be really slow !! Is it usefull ?
> >
> >FP itself is at maybe 10x faster than emulated instructions, and FP is
> >pipelinable. so if you don't have a FPU, it's _necessarily_ slow.
> >come on.
> 
> Hi, I think 10 times is a much to low assumption. I would
> see it around 1:100.

for the numbers : you're probably closer :
 - FP can be pipelined and interleaved, traps are serialising.
 - SRB has some overhead
 
however, F-CPU's operations are quite useful : they are in 64 bits
format, and alignment requires only a few cycles. 32-bit FP should be
relatively easy.

> >And don't forget your P&H books :-) (you know,
> >"what is the definition of RISC"...)
> >Do you have an idea ?
> 
> Run Imitated Softcode from Cache? :)

among other useful things :-)

> JG
WHYGEE
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