Machine Forth and ANS

["Stephen Pelc" <sfp@xxxxxxxxxxxxxxxxxx>]

theFox said: 
> >Chuck also felt that ANS Forth was missing out on some
> >good innovation like @+ which could help write faster code without
> >needing super-optimizers.  
> 
> That is true he did make that point.  As he said if you use it it
> will signifigantly change the style of your code.

The arguments are *NOT* about whether @+ or the use of an 
address register are technically good/useful. I and others such 
as Phil Koopman have discussed and implemented (especially in 
silicon designs) the use of address registers in stack machine 
VMs.

The discussion is really about whether the address register(s)
needs to be exposed in the Forth VM (not necessarily the same
as the stack machine VM). This affects the complexity of the 
compiler, but I would argue that if I can produce better code 
generation, this is *much* less complex than having to produce a 
new piece of silicon.

> I think the ANS standards team has a
> pretty obvious bias to declare that Forth was frozen fifteen years ago and
> that they were made keepers of the crystal.
Complete and utter rubbish. I note that since ANS, both MPE and 
Forth Inc have produced optimising compilers that deal with ANS 
source code. What ANS Forth (or any other standards committee) 
does do is to document common practice. An effect of this is to 
make it clear what code is portable and what is not. This is 
very different from restricting change.

Stephen

--
Stephen Pelc, sfp@mpeltd.demon.co.uk
MicroProcessor Engineering Ltd - More Real, Less Time
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