Re: I found a FORTH stack optimzer, but could use a better version.

On Jan 9, 9:57=A0am, "Rod Pemberton" <do_not_h...@[EMAIL PROTECTED]
> wrote:
> > "Jenny Brien" <jennybr...@[EMAIL PROTECTED]
> wrote in message
>
>
> Yes, you're correct. =A0With Chapman's solution, SWAP is fast but ROT is
> unimplemenable without an "rstack". =A0The key feature of his solution
is =
the
> elimination of the rstack for "most" operators. =A0ROT apparently wasn't
> presented because it (and probably -ROT,ROLL) needs a single tem****ary
> location, i.e., >R, R>. =A0The tem****ary location happens to be on the
rst=
ack
> for FORTH, but could be an available register or memory location for
x86..=
..
> Since I like the other perceived advantages, a pure x86 solution for ROT
> might be the best choice.

Wherever you put them, you will need one space apart from the stack
for each item that you want to manipulate.
>
> > For a complete set of operators you also need to be
> > able to push and pop between both registers and the rstack.
>
> What do you consider "a complete set of operators"? =A0Or, a good set of
F=
ORTH
> stack operators?

I'm interested in the minimal set needed to implement the normal Forth
stack operators. Since I shall need an rstack anyway, I think adding
that to Chapman's quarks might be a reasonable compromise.

To recap:  The top two stack items are in registers T and N, the rest
on the hardware stack

The Quarks:

	DIP   T=3DN
      DRIP  N=3DT
      TUCK  push a copy of T
      TAKE  pop to T
      NUP   push a copy of N
      NIP   pop to N

To which add:

	T>R    push a copy of T to the rstack
      R>T    pop rstack to T
	N>R    push a copy of N to the rstack
      R>N    pop rstack to N


  	: ROT  >R SWAP R> SWAP ; translates to the quarks

	T>R DIP NIP  NUP DRIP TAKE  NUP DRIP R>T  NUP DRIP TAKE

Simplification:

	DIP NIP NUP DRIP =3D DIP
      DIP TAKE  =3D TAKE
      DRIP R>T  NUP DRIP TAKE =3D R>N

leaving  R>T TAKE NUP R>N