Forth for PDP-11 - test-drb@ccmp.vtda.org

25 Jun 2002

...
 From: "Zane H. Healy"
&lt;healyzh(a)aracnet.com&gt;

 > SOL-11 - A Small Language and OS for the PDP-11
 > 
 > SOL is a small, non-standard, stand-alone FORTH kernel containing 
 > everything that is required to edit, store, recall, compile, and run 
 > programs on PDP-11 microcomputers. It is intended for a minimum 
 > operating system and programming environment. The FORTH language offers 
 > full access to the complete hardware. Device drivers for the console and 
 > some block devices are included. 
This is so cool!  

  > Supported Hardware
 > 
 >      * PDP-11 CPU with EIS (required)
 >      * 8K to 28K words of memory 
Dang, the EIS requirement sucks!  This would be perfect for PDP-11/03's and
SBC-11/21's.  Unfortunatly the /03 needs the KEV11 option, and the SBC-11/21
is just plain out of luck.

  Presumably it ignores the MMU (but doesn't
object if one is present, as 
 few machines have EIS but no MMU).

       * console terminal (preferrably VT100)
      * RX01/RX02 floppy disk drives
      * RL02 disk drive
      * TU58 tape drive  
 I assume it needs the CPU, RAM, console and at least one of the mass 
 storage devices. It can't need _all_ the drives, surely? 
It only needs one of the drives.

I just built it and booted the RL02 image on SIMH.  It looks pretty cool, of 
course I don't know FORTH, so can't actually do anything....

I suspect the TU58 option means that it's possible to run this on a PDP-11
that doesn't have any drives, but has two SLU's, just run a TU58 emulator on
a PC.

   The
Sources

 SOL is written in PDP-11 assembly language and FORTH. The BTN11 
 assembler (version 0.9 or later) is required to compile the assembly 
 part of SOL.
 40187   2001-07-17   sol-11.tar.gz   version 0.4  
 Sounds like just what I need (given that I have all of the supported 
 hardware!). I will take a look. Thanks.... 
You'll want a UNIX box to build everything.  If you don't have a way to
build the images I can through them up on my FTP site (if anyone needs this
it would be best to send me a private email so I'm sure to see the request).

Now to go googling for some FORTH documentation...

			Zane

Hi
 Try:

 http://www.forth.org/

 For I/O, you may need to look at the source code some.
It varies from amchine to machine.
 Everything in Forth is a word. A word can be as short as :
or longer. These words have actions. Some expect a string,
as in : expects a name and ." expect a string. Words that
start with . are usually some kind of print. The sequence:

4 .

will print the number 4. Here is another fun definition:

: .H BASE @ SWAP HEX U. BASE ! ;

DECIMAL 45 .H

Disk I/O on fig Forth was block I/O. To access the first
block:

0 BLOCK ( returns the address of the buffer, usually 1K )

If you type:

 UPDATE FLUSH

it will write the buffer back to the disk.
 You could modify the data by:

 55 0 BLOCK !
 UPDATE FLUSH

Not a good idea to try until you know what damage is done.
The site I just sent does have some tutorials but remember
there were several standards. Most are similar but some
will be different enough to cause troubles. Examples:

 2 NOT

 will return different values for fig and F89. I forget
which but one will be 0 and the other will be FFFD hex
or -3. One complements the flag and the other complements
the bits.
 A good book to find is called "Starting Forth" by Leo Brodie.
Dwight