[OpenBIOS] [RFC v2] Pretty-print reg property

[Segher Boessenkool]

> +\ Helpers: Convert number of cells into number of bytes
> +\ TODO honor cell size, currently assumes 4 (wrong for sparc64)
> +: my-#acellbytes ( -- #bytes)
> +  my-#acells 4 *
> +;

Device tree property "cells" aren't Forth cells; that's why the
documentation always talks about "integer as encoded with encode-int",
i.e., four bytes big-endian twos' complement.

> +: .p-reg ( data len -- )
> +  swap >r 0
> +  begin 2dup > while
> +    dup r@ + c@
> +    ( len n ch )
> +    pocket tohexstr dup 2 <> if ." 0" then type

: 0.r ( u minlen -- )  0 swap <# 1 ?DO # LOOP #s #> type ;
and then you can use here:
2 0.r

> +    1+
> +    dup my-#acellbytes my-#scellbytes + mod my-#acellbytes = if

It is very expensive to use the tree queries in the loop.

> +      ."  "
> +    then
> +    dup my-#acellbytes my-#scellbytes + mod 0= if
> +      2dup <> if
> +        cr 0 begin ."  " 1+ dup d# 26 >= until drop

26?  Why that?

> +      then
> +    then
> +  repeat
> +  2drop r> drop
> +;

Maybe something like this:

: .p-reg ( prop len -- )
  >r >r my-#scells my-#acells dup r> r> bounds ?DO
  2dup = IF cr THEN          \ start of line
  dup 0= IF 2 spaces THEN    \ start of "size" part
  dup 3 and 0= IF space THEN \ make numbers more readable
  i c@ 2 0.r                 \ print byte
  1- 3dup nip + 0= IF drop dup THEN  \ update counter
  LOOP ;

(untested, mind the bogons).

> +\ HELPER: get #size-cells value (from parent)
> +\ Legal values are 1..4 (we may optionally support longer addresses)
> +: my-#scells ( -- #size-cells )
> +  my-self ?dup if >in.device-node @ else active-package then
> +  ?dup if >dn.parent @ then
> +  ?dup if
> +    " #size-cells" rot get-package-property if 2 exit then
> +    \ we don't have to support more than 4 (and 0 is illegal)
> +    decode-int nip nip 4 min 1 max
> +  else
> +    2
> +  then
> +;

Default for #size-cells is 1, not 2.


Segher