Re: [Flashforth-devel] FlashForth 2-Dimensional arrays?

[Mikael N. <mik...@fl...>]

Sorry Craig,

I cannot think of any good way to do that in FF.

Once you are executing in the DOES> part, which part of the 2ARRAY word,
I cannot think of any way to get back to defined array word to fetch a 
size from flash.
That address is gone from the return stack.
Storing the size in flash can be done in the CREATE part with I, or 
FLASH , RAM
But when the DOES> part is executing, there is no link to the array 
word.

The only way I can think of is to initialize the size of each array in 
ram after every warm start.

Except, there is a way :-) Not tested or complete, but you get the idea.

: 2array ( col, row -- addr )
   \ create a word which points to a data area in flash
   flash create
   \ append the row size in flash
   dup ,
   \ append the start of the ram buffer in flash
   ram here flash ,
   \ allot the the ram buffer
   cells * ram here allot
   does>
     \ Fetch the row size from flash
     @+
     \ Fetch the ram buffer address flash
     @
     \ etcetera
   ;

BR Mike

On 2019-06-02 16:55, craig bair via Flashforth-devel wrote:
> I've run into an interesting problem with FF-5 on Pic18F46K22 chips.
> 2-Dimensional arrays are really handy things.  I'm setting up a
> rolling-average filter for the output of a multi-channel A/D chip to
> take a reading from a different channel each millisecond and average
> the reading I need from the correct ring-buffer whenever needed.  The
> control routine works perfectly with a 2D-array in Forth to the limits
> that I can test it... until I shut the system down or do a reset.
> Suddenly the 2array word stops returning addresses other than for row
> Zero.
> 
> Here's the word I use, derived from Stephen Pelc's (cleaned up so it
> doesn't crash when accessed):
> \ WORD ARRAY CREATION -- 2-Dimensional ( col, row -- addr )
> \ x0y0 x1y0 x2y0 ... xny0 x0y1 x1y1 ... xny1 x0y2 ... xnym
> : 2array	\ x1 y2 -- ; [child] n1 n2 -- addr ; 2-D array
>         \ make name word, save width, calculate size, allocate
>     create over , cells * here over erase allot
>         \ run time gives address of data
>     does> dup @ rot * rot + 1+ cells +
> ;
> 
> My best initial guess is that the COMMA is storing the row length into
> a ram location so a reset clears it to zero from that point on (in a
> Harvard Architecture processor).
> 
> I can work around it by doing a specific address calculation routine
> with a 1D-array, but fixing "2array" for embedded controller would be
> better.  Any suggestions or insights?
> 
> craig
> 
> 
> 
> 
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-- 
--
Mikael