Dennis,

Try this extension to the optimizing compiler "notail.f"

{ ----------------------------------------------------------------------
Selectively disable tail recursion in the optimizing compiler

NO-TAIL-RECURSION is used just like IMMEDIATE, and disables the
tail recursion behavior of the last defined word.

The actual rule compiled for the optimizing compiler is
equivalent to

OPTIMIZE ANY foo WITH foo WITH /OPT

Note that the same effect could have been obtained via a rule
which triggered on "foo ;" instead of "ANY FOO" but this would
require the optimizer to evaluate the rule on every ";" to see
if it was preceeded by the reference to foo.
---------------------------------------------------------------------- }

OPTIMIZING-COMPILER +ORDER

: (NO-TAIL-RECURSION) ( -- )
   0 RULE@ 3 CELLS + @ (COMPILE,) /OPT ;

: NO-TAIL-RECURSION ( -- )
   LAST CELL+ CELL+ @ CODE> ['] ANY OVER OPTIMIZING >LINK ,
   ['] (NO-TAIL-RECURSION) , , ;

OPTIMIZING-COMPILER -ORDER

\ simple example:

: EMBARK ( n n -- ) R> SWAP >R SWAP >R >R ; NO-TAIL-RECURSION
: DEBARK ( -- n n ) R> R> SWAP R> SWAP >R ; NO-TAIL-RECURSION

: TEST ( -- 3 4 )
   1 2 3 4 EMBARK DROP DROP DEBARK ;

On Fri, Feb 20, 2009 at 7:31 PM, Dennis Ruffer <druffer_at_worldnet.att.net> wrote:
> Yep, I remembered to look at the VentureForth word recall to find the
> -opt and +opt pair.
>
> Messy, but probably better than adding another call. ;)
>
> Thanks!
>
> DaR
>
> On Fri, Feb 20, 2009 at 7:23 PM, Rick VanNorman <rick_at_neverslow.com> wrote:
>> The problem isn't that Dennis is trying to manipulate return addresses
>> per se, but
>> that he is trying to bury data under a subroutine's return address.
>>
>> The optimizer is replacing a nominal "CALL RESTORE RET" with "JUMP RESTORE"
>>
>> Try putting a NOOP in the sequence, as "... RESTORE NOOP ;" or turn
>> off optimization
>> with "-OPT"
>>
>> rick
>>
>>> On Fri, Feb 20, 2009 at 7:05 PM, Leon Wagner <leon_at_forth.com> wrote:
>>>> It looks like you are trying to manipulate the return address in SAVE =
>>>> and RESTORE. You can't do that in a Standard program. In both cases, =
>>>> you begin with R> but you did not put anything on the return stack prior =
>>>> to that.
>>>>
>>>>> -----Original Message-----
>>>>> From: sftalk-bounce_at_forth.com=20
>>>>> [mailto:sftalk-bounce_at_forth.com] On Behalf Of Dennis Ruffer
>>>>> Sent: Friday, February 20, 2009 4:59 PM
>>>>> To: sftalk_at_forth.com
>>>>> Subject: [sftalk] What's this?
>>>>>=20
>>>>> I'm finding a strange problem with the pfDatabase plug-in I published
>>>>> at: http://vf-plugins.googlecode.com/files/pfDatabase.zip. It
>>>>> involves code that saves and restores the file information to the
>>>>> return stack. The code is defined like this:
>>>>>=20
>>>>> : SAVE ( -- ) ( R: -- f# db# r# ) R> R# @ >R DB# @ >R F# @ >R >R ;
>>>>> : RESTORE ( -- ) ( R: f# db# r# -- ) R> R> F# ! R> DB# !=20
>>>>> R> R# ! >R ;
>>>>>=20
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Received on Fri Feb 20 2009 - 18:51:33 PST