Re: [Amforth-devel] Starting amforth

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

Am 10.04.2011 22:58, schrieb D Nyberg:
> Long ago, I worked with forth extensively, but haven't for a while,  so 
> I have forgotten much. Also, that was work for an employer, so I don't 
> have copies of what I did back then. So I'll have to reinvent things I 
> remember doing.
> 
> One of the things I did back then was I made a word called run_command" 
> Which compiled a literal string like ." does, but at run time it stuffed 
> the string into the command buffer and triggered the outer interpreter.

Amforth does not (yet) provide the word EVALUATE that
is needed to implement your idea verbatim, but
its relativly easy to extend amforth to do what you want by
duplicating the turnkey code and its use in QUIT.


> That let us issue FORGET commands for words that didn't exist yet at 
> compile time,

Funny.

> etc. I've been thinking I'd like to do that again, but 
> this time maybe set up an amforth so that on cold boot it copies a 
> string (if it exists) from eeprom into the command buffer, then begins 
> execution.

What is a cold boot? esp what makes it different from a warm boot? The
atmega provide the reason of the reset in the status register and
amforth copies this information into a register (R10). Your turnkey
code may use that information to distinguish between e.g. a power on
reset or a watchdog reset (details are in the datasheets for the
MCUSR register).

> On warm boot, doesn't copy the string. It could be made even  
> a little more fancy, with maybe a few seconds count down before it runs 
> the buffer, and read ISR checks any received character for ^C and warm 
> boots if it sees one. I think that would make it very easy to develop 
> code in the field, set up automatic run if I think it's ready, break in 
> if it's not right. (I'd still want to incorporate Karl's eeprom loader, 
> or redevelop the same thing, though...)

Do I understand it correctly: whenever a CTRL-C character is received,
the currently executed word should be cancelled and the outer
interpreter is activated? Just like a reset button but with keeping
the stacks intact? Kinda of software interrupts.

Matthias