[SLOF] [PATCH slof v5 3/6] fdt: Pass the resulting device tree to QEMU

[Segher Boessenkool]

On Wed, Oct 18, 2017 at 01:45:43PM +1100, Alexey Kardashevskiy wrote:
> On 17/10/17 20:48, Segher Boessenkool wrote:
> >> -: fdt-boot-cpu ( -- bootcpu )
> >> -    s" cpu" s" /chosen" find-node get-property 0<> IF 0 EXIT THEN
> >> -    decode-int
> >> -    nip nip ihandle>phandle
> >> -    s" reg" rot get-property 0<> IF 0 EXIT THEN
> >> -    decode-int
> >> -    nip nip
> >> -;
> >> +DEFER chosen-cpu
> > 
> > Chosen cpu what?  chosen-cpu-address maybe?
> 
> May be chosen-cpu>unit or  chosen-cpu-unit ?

">" means "to" so that's a bit misleading (there is no chosen-cpu as
input to this word).  "chosen-cpu-unit" is fine with me.

> >> +VARIABLE chosen-cpu-phandle
> >> +VARIABLE chosen-cpu-ihandle
> >> +: set-chosen-cpu ( -- )
> >> +    s" /cpus" find-node  dup 0= ABORT" /cpus not found"
> >> +    child                dup 0= ABORT" /cpus/cpu not found"
> >> +    dup chosen-cpu-phandle !  0 0 rot open-node
> >> +    dup chosen-cpu-ihandle !  encode-int s" cpu" set-chosen
> >>  ;
> > 
> > You can also calculate and store the address right here (and you of
> > course do not need the phandle and ihandle if you do not want them
> > for anything else). 
> 
> I can, I just have no good taste :) Ok, I'll store chosen-cpu-ihandle only
> and use "ihandle>phandle >unit" in "chosen-cpu>unit".
> 
> > There's no need for DEFER -- just define the
> > variable before you first use it :-)
> 
> Pfff. Where would I put it?

The same place as you now have the DEFER?  DEFER and VARIABLE are very
much alike:

: VARIABLE  CREATE 0 , ;
: DEFER  CREATE POSTPONE ABORT DOES> @ EXECUTE ;

or they looks even more alike if you write this as

: VARIABLE  CREATE         0 , DOES>           ;
: DEFER     CREATE ['] ABORT , DOES> @ EXECUTE ;

(this isn't how those words are actually implemented, it is optimised
a little, but it works essentially the same way).

> Won't it confuse future readers? :) But sure I
> can do that and define chosen-cpu-ihandle in fdt.fs, and if we decide to
> use chosen-cpu-ihandle for something else - move it, and so on.

Or even not define words for the phandle and ihandle if you don't use
them.  Your choice :-)


Segher