amforth-devel

[Amforth] Compiling Label

[craig a. h. <ca...@gm...>]

I'm trying to create a label defining word which I would like to work as
follows:

xPos  yPos  s" this is the labels text"  label:  labelName

I tried this code:

\ Define a label that places itself
: label:            ( x y addr count --- )
    create
    , , , ,
    does>
        dup over over
        3 + @i swap 2 + @i moveCursor
        1+ @i @i
;

which at run time I want to return the addr and count of the labels text in
flash.

The problem is, I think, that s" doesn't compile to flash outside of a
definition.

How can I change this code to force the label's text to be stored in flash?

-- 
Craig Lindley

[Amforth] Compiling Label

[craig a. h. <ca...@gm...>]

Matthias


I tried your suggesting but sliteral cannot be compiled into another
definition for some reason.
It is not found even though I can see it in my words list and I can '
sliteral . and it is found.
Is it on some non-default wordlist ?

Maybe a better question to ask is "Is there another word like s" but
which compiles the string

into flash when executed outside of a word definition?"

-- 
Craig Lindley

Re: [Amforth] Compiling Label

[Matthias T. <mt...@we...>]

Hi Craig,

> I tried your suggesting but sliteral cannot be compiled into another
> definition for some reason.

sliteral is an immediate word. That means that you will have to use postpone
to compile it. Sorry, I forgot it..

Is the following at least somehow in the direction of what you want 
to achieve? A bit rough, I admit.

(ATmega32)> #include postpone.frt
|D=#include postpone.frt
|I=getting filenames on the host
|I=  Reading .
|I=using postpone.frt from/home/mt/Forth/amforth/amforth/lib/ans94/core
**** /home/mt/Forth/amforth/amforth
|I=getting MCU name..
|I=successfully loaded register definitions for atmega32
|F=/home/mt/Forth/amforth/amforth/lib/ans94/core/postpone.frt
|C|    1|\ always compile the next word
|C|    2|\ Implementation by Ulrich Hoffmann
|W|    3|
|S|    4|: postpone ( -- )
|S|    5|    parse-name find-name dup 0< 
|S|    6|    if \ immediate word found
|S|    7|	   drop compile compile , exit 
|S|    8|    then
|S|    9|    if \ normal word found
|S|   10|	  , exit 
|S|   11|    then
|S|   12|    drop
|S|   13|    -&13 throw 
|S|   14|; immediate
**** /home/mt/Forth/amforth/amforth/lib/ans94/core
(ATmega32)> : label: create postpone sliteral , does> dup u. ;
 ok
(ATmega32)> 42 s" hello" label: example
 ok
(ATmega32)> words
example label: postpone ...
(ATmega32)> example
3824  ok
(ATmega32)> 1+ icount itype
hello ok
(ATmega32)> example 1+ icount 2/ 1+ + @i .
3824 42 ok
(ATmega32)>

The "icount 2/ 1+ +" sequence calculates the
address of the number compiled after the sliteral. 
It is due to the fact that strings are stored with 
2 characters per flash cell.

The initial 1+ is to skip the execution token of the
runtime of sliteral, which is needed to work for the
s" in compile mode. I'm not sure if that could be 
considered a bug, now that you point your fingers at 
it... I'll think about it...

"dup u." is only a debugging aid.

Matthias

Re: [Amforth] Compiling Label

[Matthias T. <mt...@we...>]

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Hi Craig,
> 
>> I tried your suggesting but sliteral cannot be compiled into
>> another definition for some reason.
> 
> sliteral is an immediate word. That means that you will have to use
> postpone to compile it. Sorry, I forgot it..

A even better solution would be using s, (s-comma)

: label: create s, , does> dup . ;

With this definition, the at least problematic 1+
to skip an XT is no longer necessary

> (ATmega32)> 42 s" hello" label: example ok (ATmega32)> words 
> example label: postpone ... (ATmega32)> example 3824  ok 
> (ATmega32)> icount itype hello ok (ATmega32)> example icount 2/ 1+
> + @i . 3824 42 ok (ATmega32)>

HTH
Matthias


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Re: [Amforth] Compiling Label

[Matthias T. <mt...@we...>]

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Hash: SHA1

Hi Craig,

> I'm trying to create a label defining word which I would like to
> work as follows:
> 
> xPos  yPos  s" this is the labels text"  label:  labelName
> 
> I tried this code:
> 
> \ Define a label that places itself : label:            ( x y addr
> count --- ) create , , , , does> dup over over 3 + @i swap 2 + @i
> moveCursor 1+ @i @i ;
> 
> which at run time I want to return the addr and count of the labels
> text in flash.
> 
> The problem is, I think, that s" doesn't compile to flash outside
> of a definition.

Indeed. something like
: label:
   create
   sliteral , ,
   does>
   ...
;

may work (haven't tested it)

The sliteral takes the addr/len pair that is left from the s" in
interpreter mode and compiles it into the flash. The does> part gets
the flash address instead of the RAM addresses. Note that
when using the label: word, the s" ... " and the "label:" must be
on the same line, line breaks wont work, since the s" leaves
addresses from the terminal input buffer and does not copy
the string elsewhere.

Matthias

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