Re: [f-cpu] Reamrks and suggestions about the manual

[Thomas Lavergne <thomas.lavergne@laposte.net>]

Yann Guidon wrote:
> 
> as you have remarked : there are a lot of things to change.
> But this manual is getting old and can be used as an historical
> reference... the implementation has changed too quickly to
> keep it acurate.
> 
[...]
> 
> currently, the VHDL source is the de facto reference and Cédric is
> in charge of maintaining the manual, but it's a hard task.
> 

I don't blame anyone, I just try help people in this hard task, I 
understand it was difficult to keep it up to date.

I've thinking about the instruction format problem (some instruction 
don't have a standard format) and see that all instruction can be coded 
with standard format without any change in their encoding, we just need 
these switch (old format was compatible with new) :

OpCode            Format

cachemm           r2, r1
loopentry         r2, r1   (with r2 set to 0)
halt              r2, r1   (with r2 and r1 set to 0)
... (until serialize)

byterev           r3, r2, r1
fiaprx            r3, r2, r1
fsqrtiaprx        r3, r2, r1
fsqrt             r3, r2, r1

The last four was only for uniformity with the other op in the manual.

It's possible to create a new format without reg or imm, only flag, 
because we have a suficient amount of instruction for justify it, but I 
think it was not so usefull, the format (r2, r1) allow 12 flag and it 
was sufficiently.


-- 
Thomas Lavergne                       "Le vrai rêveur est celui qui rêve
                                        de l'impossible."  (Elsa Triolet)
thomas.lavergne@laposte.net
d-12@laposte.net    ICQ:#137121910     http://assoc.wanadoo.fr/thallium/

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