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JimBoyd

Post subject: Re: Fleet Forth metacompiler redesign

Posted: Tue Feb 14, 2023 1:39 am

Joined: Fri May 05, 2017 9:27 pm
Posts: 895

I have another problem to report.
The following will not work for code words with no body:

Code:

CREATE 1  ( -- 1 )
   PUSH.ONE  LATEST NAME> !

and the reason has nothing to do with the chaining of the code fields together until they are resolved. That part works as expected.
So that I can use variables like this:

Code:

CODE ]  ( -- )
   DEY
   STATE    STY
   STATE 1+ STY
   NEXT JMP  END-CODE

there has to be a word with the same name as the variable which returns the address of the variable. This is why there is a SHADOW vocabulary and why the DEFINER word CREATE creates a shadow constant for each CREATE word. This was also the case before redesigning the metacompiler.
This normally works quite well.
The word 1 is a code word with no body in Fleet Forth. Its code field points to a place in (FIND) which pushes a one on the data stack. This is smaller than a CONSTANT with the name 1 .

Consider the source for 1 shown above.

Code:

CREATE ( -- 1 )

At this point there is a VARIABLE named 1 and a SHADOW CONSTANT of the same name. When 1 is found while interpreting, such as assembling a code word with the meta assembler, the address of this VARIABLE will be placed on the stack by the SHADOW CONSTANT 1.
The following will change 1 to a code word with no body.

Code:

PUSH.ONE LATEST NAME> !

The shadow definition of 1 will still exist and will place the address of what was the VARIABLE 1 on the data stack whenever the number 1 is encountered.

When 1 is defined in the target like this:

Code:

CODE 1  END-CODE  ( -- 1 )
   PUSH.ONE  LATEST NAME> !

or even like this:

Code:

CODE 1  ( -- 1 )
   PUSH.ONE  LATEST NAME> !
   END-CODE

no shadow constant will be created since they are not needed for code words. In the following example the host system's 1 will be found or the search string will be converted to a number. Either way a one will still be placed on the stack as intended.

Code:

CODE SPLIT  ( U -- LOBYTE HIBYTE )
   1 ,X LDA  1 ,X STY
   AYPUSH JMP  END-CODE

At least with the metacompiler version of LATEST working properly I can do this:

Code:

CODE 1  ( -- 1 )
   PUSH.ONE  LATEST NAME> !
   END-CODE

rather than this:

Code:

CODE 1  ( -- 1 )
   -2 ALLOT  END-CODE
   PUSH.ONE ,

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JimBoyd

Post subject: Re: Fleet Forth metacompiler redesign

Posted: Tue Feb 14, 2023 2:22 am

Joined: Fri May 05, 2017 9:27 pm
Posts: 895

JimBoyd wrote:

Here is the source for the metacompiler's ; and -;

Code:

: ;  ( ADR TRUE -- )
   META?
   ?BRANCH [ ' ; >BODY , ]
   ?CDP ?COMP  MCOMPILE EXIT
   [COMPILE] [
   TRUE ?PAIRS TSB ; IMMEDIATE
: -;  ( ADR TRUE -- )
   META?
   ?BRANCH [ ' -; >BODY , ]
   ?CDP ?COMP
   [COMPILE] [
   TRUE ?PAIRS TSB ; IMMEDIATE

The host system's version of -; would work with the metacompiler; however, there would be no check for a change in the size of the host dictionary.
Metacompiling colon definitions which end with ; would not work without the metacompiler's version. It is needed to compile the target version of EXIT .

The only difference between the metacompiler's version of hyphen semicolon and the host version of hyphen semicolon is the check to see if the host dictionary changed. The metacompiler's hyphen semicolon can be streamlined.

Code:

: -;  ( ADR TRUE -- )
   META?
   IF  ?CDP  THEN
   [COMPILE] -; ; IMMEDIATE

The metacompiler's semicolon can be streamlined a little as well.

Code:

: ;  ( ADR TRUE -- )
   META?  ?BRANCH [ ' ; >BODY , ]
   MCOMPILE EXIT
   [COMPILE] -; ; IMMEDIATE

The host version of hyphen semicolon is used in the metacompiler's version of hyphen semicolon.
The metacompiler's version of hyphen semicolon is used in the metacompiler's version of semicolon.

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JimBoyd

Post subject: Re: Fleet Forth metacompiler redesign

Posted: Sat Feb 18, 2023 3:05 am

Joined: Fri May 05, 2017 9:27 pm
Posts: 895

Only a few more words are needed to make the metacompiler functional.
SMUDGE-TEST checks the TARGET VOCABULARY for any smudged words. If any are smudged, something went wrong while metacompiling. Smudging a word by setting its smudge-bit cannot hide it from WITH-WORDS .

Code:

: SMUDGE-TEST  ( -- )
   WITH-WORDS
      DUP C@ $20 AND
      IF
         CR ." SMUDGED: "
         RON ID. ROFF  EXIT
      THEN
      DROP ;

SMUDGE-TEST is included in FINISH-FORTH .

PATCH-FORTH makes the target ready for use.

Code:

: PATCH-FORTH  ( -- )
   THERE 'THERE V!
   " FORTH" TFIND ?TARGET
   >BODY @ V>BODY WLINK @ OVER V!
   DUP " CURRENT" TFIND ?TARGET
   >BODY @ V>BODY V!
   DUP " CONTEXT" TFIND ?TARGET
   >BODY @ V>BODY V!
   2+ 2+
   " VOC-LINK" TFIND ?TARGET
   >BODY @ V>BODY V! ;

'THERE (tick there) points to the address in virtual memory the target will use for the coldstart value of DP , Forth's dictionary pointer.
The address in WLINK is stored in the body of the vocabulary FORTH in the target. The target's CURRENT and CONTEXT are also set to point to the target's FORTH . Setting the target's CONTEXT and CURRENT isn't strictly necessary since the target's cold start routine executes FORTH DEFINITIONS as part of the high level startup. I left this in so the new kernel image will be identical to the one created with the older metacompiler.
Finally, the target's VOC-LINK is set to point to the third cell in the target's FORTH .

FINISH-FORTH executes PATCH-FORTH , runs a few checks and switches off metacompiling.

Code:

: FINISH-FORTH  ( -- )
   PATCH-FORTH VERIFY
   [TARGET] FORTH [HOST]
   SMUDGE-TEST
   [COMPILE] FINISH
   [COMPILE] META-STATUS
   'THERE 0= ABORT" 'THERE IS ZERO"
   USER.AREA 0= ABORT" NO USER AREA"
   ; IMMEDIATE

Unless I overlooked mentioning something in the source, that will be everything needed for metacompilation. I've tested this metacompiler with the source for Fleet Forth to build a new kernel. The new kernel is identical to the original so by that measure the new metacompiler is a success.
Now to start metacompiling by inserting the first source disk.

Code:

DOPEN 1 LOAD

Here is the load block for the first source disk for Fleet Forth's kernel.

Code:

// LOAD BLOCK FOR FLEET FORTH
START
  1 FH #164 FH THRU
HEX
FINISH-FORTH

FH is 'from here' and adds the current blocks number to the number on the stack. Since the load block is block 1, this will load blocks 2 thru 165 inclusive.
When FINISH-FORTH executes, this is displayed:

Code:

2CONSTANT NOT DEFINED IN TARGET
ELAPSED TIME
 00:14:03.4 
FINISHED
METACOMPILING OFF
   STATE:    0 
   WLINK: 276D 
    HEAD: FFFF 
   HEADS:    0 
HEADLESS:    7 
  ORIGIN:  801 
   THERE: 277D 
  'THERE:  81D 
  PADDED:    2 
CONTEXT: FORTH

CURRENT: FORTH

This is not all of the source and 2CONSTANT is not defined in the target at this point. At this point, I flush the buffers and close the disk.

Code:

FLUSH  OK
DCLOSE  OK

and place the second source disk in the drive and start metacompiling.

Code:

DOPEN 1 LOAD

Here is the load block for the second source disk.

Code:

RESUME
  1 FH #37 FH THRU // REST OF KERNEL
HEX
FINISH-FORTH

Note that RESUME is used rather than START.
A similar message is displayed when finished.

Code:

ELAPSED TIME
 00:03:15.9 
FINISHED
METACOMPILING OFF
   STATE:    0 
   WLINK: 2EC8 
    HEAD: FFFF 
   HEADS:    0 
HEADLESS:   10 
  ORIGIN:  801 
   THERE: 2EDE 
  'THERE:  81D 
  PADDED:    2 
CONTEXT: FORTH

CURRENT: FORTH

All that's left is to flush the buffers, close the disk for block access and insert a destination disk for the program file.

Code:

FLUSH  OK
DCLOSE  OK

Then save the target.

Code:

TSAVE 
FILENAME? 
KERNEL  OK

TSAVE prompts for a filename.

That's about it. There are two more words for the metacompiler.
GLOSSARY displays all the words in a given vocabulary, each on its own line with some statistical data.
TLOCATE is used to locate the source for a word in the TARGET vocabulary.

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JimBoyd

Post subject: Re: Fleet Forth metacompiler redesign

Posted: Sun Feb 19, 2023 10:57 pm

Joined: Fri May 05, 2017 9:27 pm
Posts: 895

Here is the source for GLOSSARY

Code:

: GLOSSARY  ( -- )
   SETWIDTH WITH-WORDS
   CR DUP ID. TAB  NAME>
   DUP @ MACRO-CF =
   IF  >BODY COUNT QTYPE EXIT  THEN
   DUP @ TARGET-WORD-CF =
   IF
      >BODY DUP @ 16BITS U.R
      ." :" 2+ @ U.W  EXIT
   THEN
   DUP @ MUSER-CF =
   IF  >BODY C@ 8BITS .R  EXIT
   THEN
   >BODY @ U.W ;

GLOSSARY will display a MACRO's internal string.
It will display the CFA of a target word and the count of how many times that word was compiled.
If a word is the shadow of a USER VARIABLE , GLOSSARY will display its offset into the user area.
For all other words, GLOSSARY displays the contents of the first cell of the word's PFA.

Code:

TARGET GLOSSARY
   ...
LIT              9C1:  15 
BRANCH           9B9:  17 
DROP             9AE:   8 
EXIT             9A5:  71 
J                990:   0 
I                96E:   9 
LEAVE            968:   0 
UNLOOP           955:   1 
(?DO)            936:   B 
(DO)             904:   4 
?BRANCH          8D3:  1C 
2DROP            8BC:   3 
(+LOOP)          8A4:   2 
(LOOP)           865:   B 
?LEAVE           850:   1 
0EXIT            83B:   7 
?EXIT            827:   6 
   ...

Code:

SHADOW GLOSSARY
   ...
BOOT             80E 
FUSE             80B 
AUTO.SCROLL.DN  $292
KBD.BUFFER      $277
LFN-1           $258
QUOTE.MODE      $D4
   ...

The source for TLOCATE

Code:

: TLOCATE  ( -- )
   [TARGET] FORTH [HOST]
   LOCATE ;

This word is used like LOCATE . If I run into a problem while metacompiling, I can check the source of a suspect word with TLOCATE

Code:

TLOCATE ?STACK

This switches to the EDITOR vocabulary and displays the screen with the source for ?STACK .

Those are all the words for the metacompiler. I recently made changes to Fleet Forth's kernel and built the new kernel with the new metacompiler. Everything seems to work fine.
Any questions?

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JimBoyd

Post subject: Re: Fleet Forth metacompiler redesign

Posted: Thu Feb 23, 2023 3:09 am

Joined: Fri May 05, 2017 9:27 pm
Posts: 895

A few more words I glossed over.
I used ORIGIN in some of the examples. It takes a number from the data stack and makes that the value for THERE by setting TDP , target DP. The lowest value used for ORIGIN is retained in (ORIGIN) and used as the start address when saving the target with TSAVE .

I mentioned that the metacompiler has the following vocabulary structure:

Code:

FORTH
  META
    SHADOW
      FORTH
        ASSEMBLER
  EDITOR
  ASSEMBLER

I already showed the source for some words to navigate this vocabulary tree. The following seven words are immediate.
HOST makes the host FORTH vocabulary the CONTEXT and CURRENT vocabulary.
TARGET makes the target FORTH vocabulary the CONTEXT and CURRENT vocabulary.
The following words only set the CONTEXT vocabulary.
[HOST] sets it to the host FORTH vocabulary. Note the brackets.
[TARGET] sets it to the target FORTH vocabulary.
[META] sets it to the META vocabulary.
[SHADOW] sets it to the SHADOW vocabulary.
[ASSEMBLER] sets it to the metacompiler's ASSEMBLER vocabulary.
These seven words are defined in the host FORTH vocabulary so they can be found from any other vocabulary.

The variable HEADLESS is used to count the number of headerless words. PNAMES is used to count the number of padded words.

The constant DEFINER-WORD is used by the word DEF-RESET to reset the definer words. It is also used by VERIFY to show which definer words were not defined in the target source. It is also used by PATCH-CF to check if the latest word defined in the target is actually a definer word.

The constant TARGET-WORD-CF is used to determine if a word is a target word.
TARGET-WORD-CF and the constants MACRO-CF and MUSER-CF are used by GLOSSARY to display appropriate data for target words, macros and the shadows of user variables.

HSUBR is defined in the host FORTH vocabulary.

Code:

: HSUBR  ( -- )
   META?
   IF
      THERE CONSTANT ASSEMBLE EXIT
   THEN
   SUBR ;

If not metacompiling, it acts as an alias for SUBR , a word in the host system. This is so that even subroutines defined with HSUBR can be tested on the host system.
If metacompiling, it will create a constant in the TARGET vocabulary which holds the current address of THERE , target HERE . It then switches to assembling.
No header or code field is created.
The subroutine DOUBLE.COMPARE is used by four code words. This example just shows one.

Code:

HSUBR DOUBLE.COMPARE
   6 ,X LDA  2 ,X CMP
   7 ,X LDA  3 ,X SBC
   4 ,X LDA  0 ,X SBC
   5 ,X LDA  1 ,X SBC
   RTS  END-CODE
CODE DU<  ( UD1 UD2 -- F )
   DOUBLE.COMPARE JSR
   CS NOT IF
      LABEL POP3.TRUE
      DEY
      LABEL POP3.FALSE
   THEN
   6 ,X STY  7 ,X STY  INX  INX
   POPTWO JMP  END-CODE

DOUBLE.COMPARE has no header and no code field. Its address is found by using the constant DOUBLE.COMPARE in the TARGET vocabulary which is on the host.

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JimBoyd

Post subject: Re: Fleet Forth metacompiler redesign

Posted: Thu Feb 23, 2023 3:42 am

Joined: Fri May 05, 2017 9:27 pm
Posts: 895

JimBoyd wrote:

If either HEAD or HEADS are ON then the word being defined in virtual memory will have a header. HEAD is normally used to switch headers off for one word at a time. HEADS is normally zero to allow some headerless words and true to forbid headerless words.
NH is used just before a word is defined and is a shortcut for the phrase HEAD OFF .

This behavior is not necessary.
Headerless words can be prevented by redefining NH as a no-op just before metacompiling.

Code:

: NH ( -- ) ;

Once this is done and the new target is saved, the dictionary can be pruned back with EMPTY . This will expose the original NH and make the system ready for metacompilation again by removing all the TARGET and SHADOW words except the vocabularies defined in those vocabularies.
The same kernel can then be rebuilt with headerless words enabled to compare the size difference.

Given this realization, HEADS would appear to be unnecessary; however, I have a better use for it.
First, I redefine VHEADER and HEADER .
The line just before IF in the source for VHEADER is changed from this:

Code:

HEAD @ HEADS @ OR

to this:

Code:

HEAD @

Now the value of the variable HEAD will determine if a header is to be built.

The line to set HEAD in HEADER is changed from this:

Code:

HEAD ON

to this:

Code:

HEADS @ HEAD !

HEADS is now the default flag for header creation. NH switches HEAD off to prevent a word from having a header. It is then set to the value of HEADS .
A few more words will offer some interesting possibilities. NH and friends.

Code:

: CH  ( -- )  // CREATE HEADER
   HEAD ON ;
: NH  ( -- )  // NO HEADER
   HEAD OFF ;
: HEADERS  ( -- )
   HEADS ON CH ;
: NOHEADERS  ( -- )
   HEADS OFF NH ;

CH will force the creation of a header for the following word in the source just as NH will force the absence of a header for the following word in the source.
HEADERS will make creating headers the default. This is overridden for individual words with NH .
NOHEADERS will make not creating headers the default. This is overridden for individual words with CH .

START is also modified.
The following:

Code:

HEAD ON HEADS OFF

is replaced with this:

Code:

HEADERS

There are a few changes to META-STATUS

Code:

: META-STATUS
   SETWIDTH
   CR ." METACOMPILING "  RON META?
   IF  ." ON"  ELSE  ." OFF"  THEN
   ROFF
   CR ."     STATE: " STATE @ U.W
   CR ."     WLINK: " WLINK @ U.W
   CR ."   HEADERS: " HEADS @ U.W
   CR ."  HEADLESS: " HEADLESS @ U.W
   CR ."    ORIGIN: " (ORIGIN) @ U.W
   CR ."     THERE: " TDP @ U.W
   CR ."    'THERE: " 'THERE U.W
   CR ." USER AREA: " USER.AREA U.W
   CR ."    PADDED: " PNAMES @ U.W
   ORDER ; IMMEDIATE

By placing NOHEADERS at the beginning of the target source for each disk of source, an entire Forth kernel can be made headerless. CH can be used to cause a few select words to have headers.
Does this bring to mind any interesting possibilities?

[Edit: fixed a typo]

Last edited by JimBoyd on Tue Feb 28, 2023 2:01 am, edited 1 time in total.

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GARTHWILSON

Post subject: Re: Fleet Forth metacompiler redesign

Posted: Thu Feb 23, 2023 10:00 am

Joined: Fri Aug 30, 2002 1:09 am
Posts: 8543
Location: Southern California

The following is not specifically regarding a metacompiler, rather a comment on your words to direct whether or not headers are compiled:

In my '816 Forth kernel assembly-language source, I used the assembler variables HEADERS? and OMIT_HEADERS. HEADERS? gets turned on and off for local use, whereas OMIT_HEADERS is to be turned on only if you want to do the whole thing without headers (which, besides saving memory, would mean that the target computer cannot do its own compilation or assembly), or at least large sections that may have multiple places saying NO_HEADERS...<some code here>...HEADERS. This was mainly so if you want a totally headerless version, you don't have to comment-out all the invocations of the HEADERS macro which turns on the HEADERS? assembler variable.

Later I've thought I should change this to a stack-based thing (again, in the assembler, not the target computer) so you could nest more levels and still have it remember, when it gets to the end of a section, whether it was supposed to go back to laying down headers or not, rather than just automatically turning headers generation back on. The variables are used by the HEADER (no 'S' or '?' on the end) macro which normally automates the creation of each header but does nothing if it's not supposed to be creating a header at the time. I don't remember at the moment what the situation was that told me I should do this; but a problem situation I'm imagining now is where an INCLude file turns the creation of headers off and on but has no memory of what the situation should be when it finishes and returns assembly to the file that called it. Another is where you might have one or more words you want in a NO_HEADERS...HEADERS section, and if you decide to move it to a different part of the file, or even to an INCLude file, you won't have to see if you'll need to modify it.

I'm slowly laying out a board for the 65816 computer that will use this Forth. Up to now I've only run this Forth on my 65802 which is an '816 which drops into an '02 socket, meaning it gives almost all the advantages of the '816 minus the ability to address anything outside bank 0 (ie, the first 64KB). When the true '816 is up, I'll get back on the '816 Forth and possibly implement this headers-on/off stack to keep track of whether or not headers should be created at any given point in the code. Most of what I need to do for it is just finish and test the material to address data in other banks.

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

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JimBoyd

Post subject: Re: Fleet Forth metacompiler redesign

Posted: Tue Feb 28, 2023 12:37 am

Joined: Fri May 05, 2017 9:27 pm
Posts: 895

I've added two words to fetch and store the header building state.

Code:

: HEADER@  ( -- F )
   HEADS @ ;
: HEADER!  ( F -- )
   DUP HEADS ! HEAD ! ;

Since these words are not intended to be used in the middle of a word's definition, there shouldn't be anything getting in the way on the metacompiler's data stack. It's far more likely that things getting in the way would be on the auxiliary data stack, at least the way I tend to write code like Fleet Forth's kernel.

Code:

CODE ?EXIT  ( F -- )
   INX  INX
   $FE ,X LDA  $FF ,X ORA
   0= IF CS>A
   0= NOT IF CS>A  END-CODE
CODE 0EXIT  ( F -- )
   INX  INX
   $FE ,X LDA  $FF ,X ORA
   0= NOT IF CS>A
   0= IF CS>A  END-CODE
CODE ?LEAVE  ( F -- )
   INX  INX
   $FE ,X LDA  $FF ,X ORA
   0= IF CS>A
   0= NOT IF CS>A  END-CODE
CODE (LOOP)
   PLA  TAY  INY
   0= IF  // BRANCHING OUT OF WORD
   SEC  PLA  0 # ADC
   VS IF  // BRANCHING OUT OF WORD
   VS NOT IF
      A>CS  A>CS  THEN  CS-SWAP
      LABEL  LEAVE.BODY
      PLA  PLA
   THEN
   PLA  PLA
   A>CS A>CS THEN
   A>CS A>CS THEN
   LABEL EXIT.BODY
   PLA  IP STA   PLA  IP 1+ STA
   THEN THEN THEN  CS-SWAP CS>A CS>A
   LABEL NEXT
   1 # LDY
   IP )Y LDA  W 1+ STA  DEY
   IP )Y LDA  W    STA  CLC
   IP LDA  2 # ADC  IP STA
   CS NOT IF
      W 1- JMP
   THEN
   IP 1+ INC
   W 1- JMP  END-CODE

Here is an example of using HEADER@ and HEADER! . Fleet Forth has a word, SR/W , to read and write individual disk sectors. Here are the headerless words used by SR/W .

Code:

NH
: ",#NUM"  ( N -- )
   ASCII , DEMIT
   0 <# #S #> DTYPE ;
NH
: DOUT  ( ADR CNT CHAN -- )
   >SLF# CHKOUT IOERR  DTYPE ;
NH
: CBP  ( -- )  // CLEAR BP
   " B-P:3,0" COUNT 15 DOUT
   CLRCHN ?D ;
NH
: BCMD  ( S T DR ADR -- )
   RB DECIMAL
   COUNT 15 DOUT
   ",#NUM" ",#NUM" ",#NUM"
   CLRCHN ;

This does the same thing.

Code:

HEADER@  NOHEADERS
: ",#NUM"  ( N -- )
   ASCII , DEMIT
   0 <# #S #> DTYPE ;
: DOUT  ( ADR CNT CHAN -- )
   >SLF# CHKOUT IOERR  DTYPE ;
: CBP  ( -- )  // CLEAR BP
   " B-P:3,0" COUNT 15 DOUT
   CLRCHN ?D ;
: BCMD  ( S T DR ADR -- )
   RB DECIMAL
   COUNT 15 DOUT
   ",#NUM" ",#NUM" ",#NUM"
   CLRCHN ;
HEADER!

JimBoyd wrote:

By placing NOHEADERS at the beginning of the target source for each disk of source, an entire Forth kernel can be made headerless. CH can be used to cause a few select words to have headers.

Although that will work, it's not necessary. Since RESUME does not affect the building of headers, NOHEADERS would only need to be at the beginning of the target source after START on the first source disk.
START makes header building the default.
RESUME does not affect heading building.

Likewise, if the target source were in an ordinary text file and there were include files, just including the include files would not affect header building. Each include file could change whether headers are built with the words I've mentioned.

Redefining HEADERS and NOHEADERS to reclaim four bytes.

Code:

: CH  ( -- )  // CREATE HEADER
   HEAD ON ;
: NH  ( -- )  // NO HEADER
   HEAD OFF ;
: HEADER@  ( -- F )
   HEADS @ ;
: HEADER!  ( F -- )
   DUP HEADS ! HEAD ! ;
: HEADERS  ( -- )
   TRUE HEADER! ;
: NOHEADERS  ( -- )
   FALSE HEADER! ;

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JimBoyd

Post subject: Re: Fleet Forth metacompiler redesign

Posted: Thu Mar 09, 2023 3:10 am

Joined: Fri May 05, 2017 9:27 pm
Posts: 895

[BEGIN] and [UNTIL] may not be needed on systems with EVALUATE .
Some source in ram block 1.

Code:

10
" CR DUP . 1- ?DUP 0= >IN !"
COUNT EVALUATE
CR .S

and the session log.

Code:

RAM LOAD 










EMPTY  OK

When interpreting, " returns the address of a counted string. The Ansi Forth word S" returns the address of a string and its count.
Even with this taken into consideration, this example doesn't work with one of the versions of Gforth on my computers without further modification.

Code:

10
S" CR DUP . 1- ?DUP 0= SOURCE NIP AND >IN !"
EVALUATE
CR .S

My Forth treats the value of >IN as unsigned. Any value of >IN greater or equal to the size of the text stream causes WORD to return a size of zero without causing an error.
My Forth's WORD uses a the word 'STREAM to obtain the address of the current location in the text stream and its remaining length.

Code:

: 'STREAM  ( -- ADR N )
   BLK @ ?DUP
   IF
      BLOCK B/BUF
   ELSE
      TIB #TIB @
   THEN
   >IN @
   OVER UMIN /STRING ;

OVER UMIN clips the value fetched from >IN so it doesn't exceed the size of the text stream. UMIN returns the unsigned minimum of two numbers.
/STRING is a word from Ansi Forth which I found to be quite useful.

Code:

/STRING   “slash-string”   STRING
   ( c-addr1 u1 n – – c-addr2 u2 )
   Adjust the character string at c-addr1 by n characters. The
   resulting character string, specified by c-addr2 u2, begins
   at c-addr1 plus n characters and is u1 minus n characters long.

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GARTHWILSON

Post subject: Re: Fleet Forth metacompiler redesign

Posted: Thu Mar 09, 2023 3:20 am

Joined: Fri Aug 30, 2002 1:09 am
Posts: 8543
Location: Southern California

very interesting idea (in a sense looping in a string that's being interpreted) !

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

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JimBoyd

Post subject: Re: Fleet Forth metacompiler redesign

Posted: Thu Mar 09, 2023 3:51 am

Joined: Fri May 05, 2017 9:27 pm
Posts: 895

There are a few places in the source for Fleet Forth where I use EVALUATE .
The following fills in the table holding the default vector for all the deferred words defined in Fleet Forth's kernel. This is done after the vectors for the deferred words have been set.

Code:

START.I&F
" TARGET  DUP @ @ OVER 2+ ! 4 +
  END.FORGET OVER 2+ U<
  HOST >IN !"
COUNT EVALUATE  TARGET
DROP

I also use EVALUATEd strings to automate defining parameters to use while building the kernel. For example, in the source for the kernel there is the following:

Code:

$63E DEFINE DR.OFFSET

That number is the largest number of blocks a dual disk version of the 1581 drive could hold, if such a device existed. The EVALUATEd strings which follow round that number up to the closest power of 2 and set other parameters used to define words such as R/W , RAM and DR+ .

Code:

// BLOCK SUBSYSTEM PARAMETERS
// THESE PARAMETERS ARE DETERMINED
// BY THE VALUE DR.OFFSET
DR.OFFSET $100 UMAX $8000
" HOST 1 RSHIFT 2DUP SWAP U< >IN !"
COUNT EVALUATE  TARGET
NIP 7 RSHIFT DEFINE DR.OFS.HI
0 DR.OFS.HI
" HOST 1 UNDER+ 2/ ?DUP 0= >IN !"
COUNT EVALUATE  TARGET  7 + 0
HEX <# #S ASCII $ HOLD #> DECIMAL
MACRO DR.OFS.PWR
#DRIVES DR.OFS.PWR LSHIFT 0
HEX <# #S ASCII $ HOLD #> DECIMAL
MACRO RAM.OFFSET

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JimBoyd

Post subject: Re: Fleet Forth metacompiler redesign

Posted: Sun Mar 19, 2023 10:47 pm

Joined: Fri May 05, 2017 9:27 pm
Posts: 895

The source for R/W , RAM and DR+ . Note: RR/W and DR/W are DEFERred words.

Code:

CODE R/W  ( ADR BLK# R/WF CNT -- )
   BEGIN
      SEC  5 ,X LDA  DR.OFS.HI # SBC
   CS WHILE
      5 ,X STA  INY  #DRIVES # CPY
   0= UNTIL
      ' RR/W SPLIT SWAP
      # LDA  # LDY
      (EXECUTE) 0= NOT BRAN
   THEN
   DRB STY
   ' DR/W SPLIT SWAP
   # LDA  # LDY
   (EXECUTE) 0= NOT BRAN  END-CODE

: RAM  ( BLK#1 -- BLK#2 )
   RAM.OFFSET + ;

: DR+  ( BLK#1 #DR -- BLK#2 )
   7 AND  DR.OFS.PWR LSHIFT  + ;

and what gets assembled and compiled.

Code:

R/W
  3931          SEC
  3932     5 ,X LDA
  3934     8  # SBC
  3936  3951    BCC
  3938     5 ,X STA
  3940          INY
  3941     8  # CPY
  3943  3931 ^^ BNE
  3945   184  # LDA
  3947    11  # LDY
  3949  3920 ^^ BNE ' EXECUTE >BODY 6 +
  3951  2686    STY ' DRB >BODY
  3954   173  # LDA
  3956    11  # LDY
  3958  3920 ^^ BNE ' EXECUTE >BODY 6 +
29 

RAM
  9988  2497 LIT 16384 
  9992  4944 +
  9994  2469 EXIT
8 

DR+
 12004  3308 CLIT 7 
 12007  4556 AND
 12009  3308 CLIT 11 
 12012  5268 LSHIFT
 12014  4944 +
 12016  2469 EXIT
14 

The use of RAM and DR+ is mentioned here.
R/W is Fleet Forth's BLOCK reading and writing word.

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JimBoyd

Post subject: Re: Fleet Forth metacompiler redesign

Posted: Thu Mar 23, 2023 2:25 am

Joined: Fri May 05, 2017 9:27 pm
Posts: 895

The redesign of Fleet Forth's metacompiler is complete. I'm fairly certain I presented all the source and covered everything.
Any questions?

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GARTHWILSON

Post subject: Re: Fleet Forth metacompiler redesign

Posted: Thu Mar 23, 2023 2:30 am

Joined: Fri Aug 30, 2002 1:09 am
Posts: 8543
Location: Southern California

Just use it a lot to wring out any bugs, and write a good manual for it.

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

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JimBoyd

Post subject: Re: Fleet Forth metacompiler redesign

Posted: Tue Mar 28, 2023 1:52 am

Joined: Fri May 05, 2017 9:27 pm
Posts: 895

The new metacompiler's first big test was metacompiling an existing version of Fleet Forth. Since I'm using VICE instead of a real Commodore 64, the disks are actually disk images and the disk image with the new kernel was identical to the one created with the original metacompiler. I also have SEEALL to test kernels I build. Successfully loading the system loader and the utilities is a test. SEEALL showing the expected disassembly/decompilation is another.

Code:

: (SEE)  ( CFA -- )
   DUP CR .NAME
   SETWIDTH <SEE> ;
: SEE  ( -- )  ' (SEE) ;
: SEEALL  ( -- )
   WITH-WORDS  NAME> (SEE)
   COLS ?CR ;

I've simplified some of the more obscure code for the metacompiler by adding two new words. These new words use the coroutine word CO

Code:

: >META  ( -- )
   ORDER@
   META DEFINITIONS
   CO ORDER! ;
: >SHADOW  ( -- )
   ORDER@
   [SHADOW] SHADOW DEFINITIONS
   CO ORDER! ;

The word >META saves the values of CONTEXT and CURRENT to the auxiliary stack then changes the search and compile vocabularies to META . CO causes the rest of >META to run after >META's caller exits. That last part of >META restores the CONTEXT and CURRENT vocabularies.
>SHADOW does the same thing for the SHADOW vocabulary.
This source

Code:

: DEFINE  ( W -- )
   ORDER@
   [SHADOW] SHADOW DEFINITIONS
   CONSTANT  ORDER! ;

META DEFINITIONS
: MACRO  ( ADR CNT -- )
   ORDER@
   [SHADOW] SHADOW DEFINITIONS
   [HOST] MACRO ORDER! ;
HOST

: <MCONSTANT>  ( N ADR -- )
   >IN @  HEADER  >IN !
   CF,  DUP V,
   ORDER@
   [SHADOW] SHADOW DEFINITIONS [HOST]
   CONSTANT
   ORDER! ;

: <M2CONSTANT>  ( D ADR -- )
   >IN @  HEADER  >IN !
   CF,  2DUP V, V,
   ORDER@
   [SHADOW] SHADOW [HOST]
   DEFINITIONS  2CONSTANT
   ORDER! ;

: <MCREATE>  ( ADR -- )
   >IN @ HEADER >IN !  CF,
   ORDER@
   [SHADOW] SHADOW DEFINITIONS
   THERE CONSTANT
   ORDER! ;

: <<MUSER>>  ( C -- )
   CREATE
      C,
      [ HERE 2+ >A ]
   DOES>
      C@ USER.AREA + ;
: <MUSER>  ( C ADR -- )
   >IN @  HEADER  >IN !  CF,
   DUP VC,
   ORDER@
   [SHADOW] SHADOW [HOST]
   DEFINITIONS
   <<MUSER>>
   ORDER! ;
A> CONSTANT MUSER-CF

is simplified to this

Code:

: DEFINE  ( W -- )
   >SHADOW CONSTANT ;

META DEFINITIONS
: MACRO  ( ADR CNT -- )
   >SHADOW MACRO ;
HOST

: <MCONSTANT>  ( N ADR -- )
   >IN @  HEADER  >IN !
   CF,  DUP V,
   >SHADOW CONSTANT ;

: <M2CONSTANT>  ( D ADR -- )
   >IN @  HEADER  >IN !
   CF,  2DUP V, V,
   >SHADOW 2CONSTANT ;

: <MCREATE>  ( ADR -- )
   >IN @ HEADER >IN !  CF,
   >SHADOW THERE CONSTANT ;

0 VALUE MUSER-CF
: <MUSER>  ( C ADR -- )
   >IN @  HEADER  >IN !  CF,
   DUP VC,
   >SHADOW
   CREATE
      C,
      [ HERE 2+ TO MUSER-CF ]
   DOES>
      C@ USER.AREA + ;

Likewise, this source

Code:

: DEFINER  ( CFA -- )
   ['] ORDER! >BODY >R
   ORDER@  META DEFINITIONS
   CREATE
      ,  0 ,  0 , 0 ,
   [ HERE 2+ >A ]
   DOES>
      DUP 2+ SWAP @ EXECUTE ;
   A> CONSTANT DEFINER-WORD

: DEF-RESET  ( -- )
   ['] ORDER! >BODY >R
   ORDER@ META WITH-WORDS
   NAME> DUP @ DEFINER-WORD <>
   IF  DROP EXIT  THEN
   >BODY 2+ 6 ERASE ;

: VERIFY  ( -- )
   ['] ORDER! >BODY >R
   ORDER@ META WITH-WORDS
   DUP NAME> DUP @ DEFINER-WORD <>
   IF  2DROP EXIT  THEN
   >BODY 2+ @
   IF  DROP EXIT  THEN
   CR RON ID.
   ." . NOT DEFINED IN TARGET" ;

is simplified to this

Code:

: DEFINER  ( CFA -- )
   >META
   CREATE
      ,  0 ,  0 , 0 ,
   [ HERE 2+ >A ]
   DOES>
      DUP 2+ SWAP @ EXECUTE ;
   A> CONSTANT DEFINER-WORD

: DEF-RESET  ( -- )
   >META WITH-WORDS
   NAME> DUP @ DEFINER-WORD <>
   IF  DROP EXIT  THEN
   >BODY 2+ 6 ERASE ;

: VERIFY  ( -- )
   >META WITH-WORDS
   DUP NAME> DUP @ DEFINER-WORD <>
   IF  2DROP EXIT  THEN
   >BODY 2+ @
   IF  DROP EXIT  THEN
   CR RON ID.
   ." . NOT DEFINED IN TARGET" ;

The metacompiler built with these changes successfully metacompiled Fleet Forth's kernel.

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