Re: pre-announcing Forth for PIC18F chips

[email protected] wrote:
> Is there any (PIC18) Forth language documents available?

Sorry - the only 'language documents' existing at the moment are the 
forth and assembler source files.

I know how rude it is to tell users to RTFS, so I'll write a reasonable 
manual before doing the release.

At the moment, code is stable and getting better, and I'm doing some 
tidy-ups before writing the doco and demo progs. Looking at first 
pre-alpha release in 1-2 weeks.

Cheers
David

> 
> Thank you!
> 
> - Mengjin -
> 
> -----Original Message-----
> From: David McNab [mailto:[email protected]]
> Sent: Sunday, January 16, 2005 6:04 AM
> To: [email protected]; [email protected]
> Subject: pre-announcing Forth for PIC18F chips
> 
> 
> Hi gnupic and picforth people,
> 
> This is a pre-announcement of a coming Forth compiler for the PIC18Fxxx 
> chips. I've tentatively called it 'PIC18forth', but am open to 
> suggestions for a better name.
> 
> PIC18forth is radically different from the PIC16Fxxx-only PicForth 
> compiler. Almost nothing in common, since I've written PIC18forth from 
> scratch.
> 
> Quick summary of features - love them and loathe them:
> 
>   * signed/unsigned 16-bit data cells and operators
>   * software return stack
>   * data stack grows up (increasing addresses), while
>     return stack grows down (decreasing addresses)
>   * total allocated size of data+return stacks can
>     be set to anything between 16 and 1024 bytes
>   * compiler is written in Python, and is very approachable
>     and extensible, even for people new to the code
>   * integrated into gputils
>   * forth sources get compiled to relocatable assembly (.asm)
>     sources, ready for gpasm and gplink
>   * the generated code embeds a 16-bit forth vm (token threaded
>     execution model) which executes bytecodes
>   * the generated code is self-contained, and once assembled
>     and linked, can be downloaded/flashed as a standalone program
>   * FSR0 is usually used for data stack ptr, FSR1 usually
>     used as return stack ptr, FSR2 used as general purpose
>     pointer
>   * full support for locals (John Hopkins syntax, data
>     gets transferred from data stack to a frame on return stack
>   * vm design favours code density over execution speed
>   * contents of 'code .. end-code' definitions are included
>     verbatim in generated assembly source (with '\' comments
>     changed to ';')
>   * the defining-words 'primitive .. end-primitive' can be
>     used in place of 'code .. end-code', to define a word
>     in assembler which will be available as a single-byte
>     vm instruction - easy to add/remove primitives at will
>   * maps to von Neumann memory model, with addresses <8000H
>     treated as RAM addresses, and addresses>=8000H treated
>     as program ROM addresses
> 
> If you're currently hacking with PIC18Fxxx chips, and are interested in 
> trying out PIC18forth, please mail me and I'll put you on a list for 
> pre-alpha-testers.
>