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Re: Static Single Assignment form to Stack allocation

From "Rod Pemberton" <buzz@notnotnontnooatno.cmm>
Newsgroups comp.lang.forth
Subject Re: Static Single Assignment form to Stack allocation
Date 2015-02-07 21:04 -0500
Organization Aioe.org NNTP Server
Message-ID <op.xtpuo5dlv6dtjm@localhost> (permalink)
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On Sat, 07 Feb 2015 17:51:57 -0500, Aliaksei Chapyzhenka  
<alex.drom@gmail.com> wrote:

> : SWAP OVER >R >R DROP R> R> ;

This is probably not what you want.  OVER usually requires more
code in assembly than other operations.  I.e., you've slowed down
SWAP by using OVER and made SWAP dependent on OVER being implemented
as a "primitive" or low-level Forth word or operation. You want to
minimize use of ROT and OVER because they're complicated operations
on most microprocessors relative to other simpler stack operations.
They don't work well with LIFO stacks and direct access of stack items.

> : DUP >R R@ R> ;

This isn't a good idea either.  Instead of being able to fetch
the top data item on the data stack directly, you've migrated
the operation to where you can, i.e., the return stack using R@ .
It's better to have DUP be implemented as a "primitive" or
low-level Forth word or operation.  DUP is a heavily used word
in Forth, at least.  You can look at Philip Koopman's instruction
frequencies:

http://users.ece.cmu.edu/~koopman/stack_computers/sec6_3.html

Anton Ertl also has Forth instruction frequencies, somewhere.

> : DROP DUP XOR XOR ;

That doesn't do what you think it does.  DUP creates two stack
items.  XOR XOR converts one of them to zero.  But, you still
have two items on the stack, the second one being a zero.
DROP needs to _reduce_ the number of items on the stack.
Reducing or increasing the number of items on a stack usually
requires a "primitive" or low-level Forth word or operation.

I'd recommend implementing these as "primitives" or low-level
Forth words or operations:

> R R> DUP DROP SWAP OVER ROT

Those aren't the absolute minimum since a couple of those can
be eliminated, but it's close to it.  Eliminating more slows
down Forth code and would like slow down your code too.
Optionally, you may want R@ too.  R@ is not generally needed,
except maybe for implementations of I and J .  If you're directly
accessing the stack, similar to parameters in C, you'll need
PICK and the reverse operation, i.e., perhaps named PLACE .

IIRC, Alex McDonald is using an optimizer, Rafts, that can
determine optimal sequences for Forth words.

I'm using an optimizer also.  It's a highly modified, private
version of Peter Sovietov's Forth Wizard:

http://www.sovietov.com/app/forthwiz.html

I've added a huge number of stack operations.   I can select
most any set of Forth stack operations, x86 style stack
operations, Rob Chapman's "Stack Quarks", or use of temporary
variables, etc to determine optimal sequences.  I also updated
it to use the return stack, so more complicated operations
can be solved.


E.g., for 2NIP (a b c d -- c d ), in terms of
R> >R R@ DUP DROP SWAP OVER ROT -ROT

rot drop rot drop
> r -rot drop drop r>
rot drop -rot -rot drop
-rot -rot drop rot drop
> r >r drop drop r> r>r swap drop r> rot dropr swap drop swap drop r>
(keeps on going ...)

If I don't want ROT or OVER etc I can unselect them
and re-run.

If you want 2NIP in terms of
2R> 2>R 2R@ 2DUP 2DROP 2SWAP 2OVER 2ROT -2ROT

2swap 2drop
2>r 2drop 2r>
2dup 2rot 2drop 2drop
2dup -2rot 2drop 2drop
2over 2rot 2drop 2drop
2>r 2drop 2r@ 2r> 2drop
2dup 2>r 2drop 2drop 2r>
2dup 2rot 2swap 2drop 2drop
2dup 2rot 2rot 2drop 2drop
2dup -2rot 2swap 2drop 2drop
  (keeps on going ...)

An example using the return stack, e.g., 2R>
(a b -- ) (R: -- a b)

swap >r >r
over >r >r drop
dup rot >r >r drop
dup rot >r drop >r
dup -rot drop >r >r
swap >r dup >r drop
swap dup >r drop >r
over >r swap drop >r
over rot >r drop >r
  (keeps on going ...)

I didn't post other solutions in terms of stack
operators that I defined since you wouldn't understand
what my naming means, but they're available also.
E.g., directly retrieving from specific locations
to specific data or return stack locations.

Obviously, this optimizer doesn't find solutions
using arithmetic operations or other Forth words.
The Rafts optimizer Alex McDonald is using should.


Rod Pemberton

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Thread

Static Single Assignment form to Stack allocation Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-02-05 20:01 -0800
  Re: Static Single Assignment form to Stack allocation Paul Rubin <no.email@nospam.invalid> - 2015-02-05 21:00 -0800
    Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-06 02:15 -0500
      Re: Static Single Assignment form to Stack allocation Paul Rubin <no.email@nospam.invalid> - 2015-02-06 12:07 -0800
        Re: Static Single Assignment form to Stack allocation Jan Coombs <Jan-54 <jenfhaomndgfwutc@murmic.plus.com>> - 2015-02-08 22:38 +0000
          Re: Static Single Assignment form to Stack allocation Paul Rubin <no.email@nospam.invalid> - 2015-02-08 14:55 -0800
            Re: Static Single Assignment form to Stack allocation Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-02-08 19:59 -0800
  Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-06 13:15 +0000
  Re: Static Single Assignment form to Stack allocation anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-06 13:22 +0000
    Re: Static Single Assignment form to Stack allocation Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-02-06 11:16 -0800
      Re: Static Single Assignment form to Stack allocation Paul Rubin <no.email@nospam.invalid> - 2015-02-06 12:05 -0800
      Re: Static Single Assignment form to Stack allocation hughaguilar96@gmail.com - 2015-02-06 16:44 -0800
        Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-06 23:41 -0500
      Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-06 23:41 -0500
        Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-07 19:22 +0000
          Re: Static Single Assignment form to Stack allocation Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-02-07 13:09 -0800
            Re: Static Single Assignment form to Stack allocation "Elizabeth D. Rather" <erather@forth.com> - 2015-02-07 11:25 -1000
              Re: Static Single Assignment form to Stack allocation Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-02-07 14:09 -0800
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-07 22:32 +0000
                Re: Static Single Assignment form to Stack allocation Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-02-07 14:51 -0800
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-08 00:04 +0000
                Re: Static Single Assignment form to Stack allocation Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-02-07 17:03 -0800
                Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-07 21:04 -0500
                Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-07 21:10 -0500
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-08 10:57 +0000
                Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-07 21:05 -0500
            Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-07 22:24 +0000
          Re: Static Single Assignment form to Stack allocation "Elizabeth D. Rather" <erather@forth.com> - 2015-02-07 11:21 -1000
          Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-07 20:11 -0500
            Re: Static Single Assignment form to Stack allocation "Elizabeth D. Rather" <erather@forth.com> - 2015-02-07 15:35 -1000
              Re: Static Single Assignment form to Stack allocation "Elizabeth D. Rather" <erather@forth.com> - 2015-02-07 16:52 -1000
                Re: Static Single Assignment form to Stack allocation hughaguilar96@gmail.com - 2015-02-08 10:21 -0800
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-08 20:09 +0000
                Re: Static Single Assignment form to Stack allocation "Elizabeth D. Rather" <erather@forth.com> - 2015-02-08 17:15 -1000
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-09 12:00 +0000
                Re: Static Single Assignment form to Stack allocation albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-02-09 13:05 +0000
                Re: Static Single Assignment form to Stack allocation "HAA" <someone@microsoft.com> - 2015-02-10 16:01 +1100
                Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-09 02:35 -0500
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-09 12:03 +0000
              Re: Static Single Assignment form to Stack allocation hughaguilar96@gmail.com - 2015-02-08 10:13 -0800
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-08 20:21 +0000
                Re: Static Single Assignment form to Stack allocation hughaguilar96@gmail.com - 2015-02-09 22:49 -0800
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-10 12:12 +0000
                Re: Static Single Assignment form to Stack allocation albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-02-10 12:54 +0000
                Re: Static Single Assignment form to Stack allocation Mark Wills <markwills1970@gmail.com> - 2015-02-10 06:30 -0800
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-10 14:53 +0000
                Re: Static Single Assignment form to Stack allocation "Elizabeth D. Rather" <erather@forth.com> - 2015-02-10 08:20 -1000
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-10 14:33 +0000
                Re: Static Single Assignment form to Stack allocation albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-02-10 19:09 +0000
                Control-flow stack (was: Static Single Assignment ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-10 14:29 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) "Alex McDonald" <blog@rivadpm.com> - 2015-02-10 15:49 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-02-10 17:56 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) "Alex McDonald" <blog@rivadpm.com> - 2015-02-10 20:53 +0000
                Re: Control-flow stack "Elizabeth D. Rather" <erather@forth.com> - 2015-02-10 13:08 -1000
                Re: Control-flow stack awegel@arcor.de (Alexander Wegel) - 2015-02-11 03:15 +0100
                Re: Control-flow stack hughaguilar96@gmail.com - 2015-02-10 18:47 -0800
                Re: Control-flow stack Unknown <dog@gmail.com> - 2015-02-17 07:13 +0000
                Re: Control-flow stack anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-11 17:59 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-02-11 01:30 -0800
                Re: Control-flow stack (was: Static Single Assignment ...) "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-10 18:43 -0500
                Re: Control-flow stack (was: Static Single Assignment ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-11 17:46 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) "Alex McDonald" <blog@rivadpm.com> - 2015-02-11 22:39 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) "Alex McDonald" <blog@rivadpm.com> - 2015-02-11 22:42 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-12 09:52 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) "Alex McDonald" <blog@rivadpm.com> - 2015-02-12 10:28 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) hughaguilar96@gmail.com - 2015-02-11 20:23 -0800
                Re: Control-flow stack (was: Static Single Assignment ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-12 07:21 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) hughaguilar96@gmail.com - 2015-02-12 18:33 -0800
                Re: Control-flow stack awegel@arcor.de (Alexander Wegel) - 2015-02-13 04:46 +0100
                Re: Control-flow stack "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-13 06:48 -0500
                Re: Control-flow stack awegel@arcor.de (Alexander Wegel) - 2015-02-13 13:40 +0100
                Re: Control-flow stack albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-02-13 15:49 +0000
                Re: Control-flow stack awegel@arcor.de (Alexander Wegel) - 2015-02-14 03:47 +0100
                Re: Control-flow stack anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-13 16:09 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-13 15:20 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) hughaguilar96@gmail.com - 2015-02-13 21:31 -0800
                Re: Control-flow stack awegel@arcor.de (Alexander Wegel) - 2015-02-14 03:47 +0100
                Re: Control-flow stack (was: Static Single Assignment ...) hughaguilar96@gmail.com - 2015-02-14 19:22 -0800
                Re: Control-flow stack (was: Static Single Assignment ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-15 11:09 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) hughaguilar96@gmail.com - 2015-02-15 16:57 -0800
                Re: Control-flow stack (was: Static Single Assignment ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-16 14:41 +0000
                Re: Control-flow stack (was: Static Single Assignment ...) hughaguilar96@gmail.com - 2015-02-16 18:43 -0800
                Re: Control-flow stack Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-02-10 22:04 +0000
                Re: Control-flow stack Harold <hzrabbie@gmail.com> - 2015-02-10 16:58 -0800
                Re: Control-flow stack Bernd Paysan <bernd.paysan@gmx.de> - 2015-02-11 02:51 +0100
                Re: Control-flow stack albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-02-11 11:34 +0000
                Re: Control-flow stack Harold <hzrabbie@gmail.com> - 2015-02-11 08:17 -0800
                Re: Control-flow stack "Elizabeth D. Rather" <erather@forth.com> - 2015-02-10 16:37 -1000
                Re: Control-flow stack hughaguilar96@gmail.com - 2015-02-10 18:57 -0800
                Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-10 18:44 -0500
                Re: Static Single Assignment form to Stack allocation "Elizabeth D. Rather" <erather@forth.com> - 2015-02-10 14:49 -1000
                Re: Static Single Assignment form to Stack allocation hughaguilar96@gmail.com - 2015-02-10 18:16 -0800
                Re: Static Single Assignment form to Stack allocation Mark Wills <markwills1970@gmail.com> - 2015-02-11 00:35 -0800
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-11 09:35 +0000
                Re: Static Single Assignment form to Stack allocation Mark Wills <markwills1970@gmail.com> - 2015-02-11 03:06 -0800
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-11 14:27 +0000
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-11 14:40 +0000
                Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-12 20:02 -0500
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-13 11:42 +0000
                Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <buzz@notnotnontnooatno.cmm> - 2015-02-13 07:44 -0500
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-13 14:20 +0000
                Re: Static Single Assignment form to Stack allocation "Elizabeth D. Rather" <erather@forth.com> - 2015-02-13 10:32 -1000
                Re: Static Single Assignment form to Stack allocation "Rod Pemberton" <bork@lllljunkqwer.cpm> - 2015-03-29 16:27 -0400
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-03-29 22:46 +0100
                Re: Static Single Assignment form to Stack allocation "Elizabeth D. Rather" <erather@forth.com> - 2015-03-29 15:24 -1000
                Re: Static Single Assignment form to Stack allocation hughaguilar96@gmail.com - 2015-03-30 04:44 -0700
                Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-03-30 15:33 +0100
                Re: Static Single Assignment form to Stack allocation anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-11 18:03 +0000
                Re: Static Single Assignment form to Stack allocation Bernd Paysan <bernd.paysan@gmx.de> - 2015-02-12 00:16 +0100
                Re: Static Single Assignment form to Stack allocation anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-02-12 07:08 +0000
            Re: Static Single Assignment form to Stack allocation "Alex McDonald" <blog@rivadpm.com> - 2015-02-08 10:51 +0000

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