META26

\ Win32 Forth Metacompiler
\ Andrew McKewan, November 1995
\ Many thanks to Henry Laxen & Michael Perry for F83

\ SYS-WARNING-OFF        \ don't warn about use of system words
\ echo on


time-reset

ONLY FORTH ALSO DEFINITIONS


ANEW METACOMPILER
NOSTACK
WARNING OFF
: HAVE ( -- f ) DEFINED NIP 0<> ;

: >WORDLIST  ( voc-cfa -- wordlist )   VCFA>VOC ;  ( Win32Forth )


\ ======================================================================
\ Define the wordlists that are used in the metacompiler

VOCABULARY META         \ metacompiler implementation
VOCABULARY TARGET       \ target words
VOCABULARY TRANSITION   \ special compiling words
VOCABULARY FORWARD      \ forward references

' META        >WORDLIST CONSTANT META-WORDLIST          ( *SYSDEP* )
' TARGET      >WORDLIST CONSTANT TARGET-WORDLIST        ( *SYSDEP* )
' FORWARD     >WORDLIST CONSTANT FORWARD-WORDLIST       ( *SYSDEP* )
' TRANSITION  >WORDLIST CONSTANT TRANSITION-WORDLIST    ( *SYSDEP* )
' ASSEMBLER   >WORDLIST CONSTANT ASSEMBLER-WORDLIST     ( *SYSDEP* )


\ We will use the following search orders:
: IN-FORTH        ONLY FORTH ALSO DEFINITIONS  ;
: IN-META         ONLY FORTH ALSO META ALSO DEFINITIONS ;
: IN-TRANSITION   ONLY FORWARD ALSO TARGET ALSO TRANSITION ;



IN-META

\ ======================================================================
\ Memory Access Words

HEX 00008000     VALUE ORIGIN DECIMAL   \ where target image will run

CREATE IMAGE  40000 ALLOT               \ where target image is built
       IMAGE  40000 ERASE  ( clean start )

VARIABLE DP-T   ORIGIN               DP-T !   \ target dictionary pointer

: ORG   ( taddr -- )  DUP TO ORIGIN  DP-T ! ;

: THERE   ( taddr -- addr )     ORIGIN -  IMAGE +  ;
: C@-T    ( taddr -- char )     THERE C@ ;
: @-T     ( taddr -- n )        THERE @  ;
: C!-T    ( char taddr -- )     THERE C! ;
: !-T     ( n taddr -- )        THERE !  ;
: HERE-T  ( -- taddr )          DP-T @   ;
: ALLOT-T ( n -- )              ( HERE-T THERE OVER ERASE )  DP-T +!  ;
: C,-T    ( char -- )           HERE-T C!-T   1 DP-T +!  ;
: ,-T     ( n -- )              HERE-T  !-T   4 DP-T +!  ;
: S,-T    ( addr len -- )       0 ?DO  COUNT C,-T   LOOP DROP  ;

: ALIGN   HERE-T ALIGNED HERE-T - ALLOT-T ;

: TARGET-SAVE  ( addr len -<filename>- )
         bl word save-file ;
\        BL WORD COUNT R/W BIN CREATE-FILE ABORT" Cannot create file"   >R
\        R@ WRITE-FILE ABORT" Error writing Dictionary"
\        R> CLOSE-FILE ABORT" Cannot close file" ;

\ : +ORIGIN  ( n -- addr )  CELLS ORIGIN + THERE ;

\ ======================================================================
\ Target Memory Dump

: .2   ( n -- )   0 <# # # #> TYPE SPACE ;

: EMIT.  ( n -- )
   ( 127 AND)  DUP BL 127 WITHIN 0= IF  DROP [CHAR] .  THEN  EMIT ;

: DUMP  ( taddr len -- )  ( hex byte format with ascii )
    BASE @ >R HEX  OVER + DUP ROT
    ?DO  CR I 4 .R SPACE SPACE   I 16 + OVER MIN I
         2DUP DO  I C@-T .2  I J 7 + = IF SPACE THEN  LOOP
         2DUP -  16 OVER - 3 *  SWAP 8 < -  1+ SPACES
         DO  I C@-T EMIT.  LOOP
         START/STOP
    16 +LOOP  DROP  R> BASE ! ;

\ ======================================================================
\ Modify assembler to place code into target

     ' HERE-T     ASSEMBLER  IS HERE    META
     ' C,-T       ASSEMBLER  IS C,      META
     ' ,-T        ASSEMBLER  IS T,      META
     ' ,-T        ASSEMBLER  IS ,       META
     ' @-T        ASSEMBLER  IS t@      META
     ' !-T        ASSEMBLER  IS t!      META

\ ASSEMBLER MACROS
: MACRO  ASSEMBLER DEFINITIONS : ;
: END-MACRO   POSTPONE ; META DEFINITIONS ; IMMEDIATE


\ ======================================================================
\ Define Meta Branching Constructs

: ?CONDITION  TRUE - ABORT" Conditionals not paired" ;

: ?>MARK      ( -- f addr )   TRUE   HERE-T   0 ,-T   ;
: ?>RESOLVE   ( f addr -- )   HERE-T SWAP !-T   ?CONDITION ;
: ?<MARK      ( -- f addr )   TRUE   HERE-T   ;
: ?<RESOLVE   ( f addr -- )   ,-T   ?CONDITION   ;

\ ======================================================================
\ Meta Compiler Forward Reference Linking

\ Structure of a forward reference (cell offsets from BODY)
\       0       - target address if resolved
\       1       - resolved flag
\       2       - link to previous forward reference


VARIABLE FORWARD-LINK   \ linked list of FORWARD words (for .UNRESOLVED)
0 FORWARD-LINK !

: MAKE-CODE   ( pfa -- )
        @ ,-T   ;
: LINK-BACKWARDS   ( pfa -- )
        HERE-T OVER @ ,-T   SWAP !   ;
: RESOLVED?   ( pfa -- f )
        CELL+ @   ;

: DO-FORWARD   ( -- )
        DOES> DUP RESOLVED? IF  MAKE-CODE  ELSE  LINK-BACKWARDS  THEN ;

: (FORWARD)    ( taddr -- )
        GET-CURRENT >R
        FORWARD-WORDLIST SET-CURRENT
        CREATE
          , ( taddr )
          FALSE , ( resolved flag )
          HERE FORWARD-LINK @ , FORWARD-LINK !
        DO-FORWARD
        R> SET-CURRENT ;

: FORWARD:  ( -- )      \ Explicit forward reference
        0 (FORWARD) ;

: UNDEFINED   ( -- )    \ Undefined words create automatic forward reference
        HERE-T  (FORWARD)  0 ,-T  ;

\ ======================================================================
\ Create Headers in Target Image. We support only one FORTH-WORDLIST in
\ the kernel.

32 CONSTANT #THREADS     \ # of threads in FORTH-WORDLIST

CREATE FORTH-THREADS  #THREADS CELLS ALLOT
       FORTH-THREADS  #THREADS CELLS ERASE

\ Hash string to an integer (must match kernel definition!)
: HASH   ( addr len -- hashCode )
    0 -rot bounds ?do 1 lshift i c@ xor loop ;

: THREAD   ( addr len -- 'thread )      \ get vocab thread address
        HASH  #THREADS MOD  CELLS FORTH-THREADS +  ;

VARIABLE HEADS  HEADS ON
: |   HEADS OFF ;   ( make next word headerless )

: VIEW,  ( -- )
        LOADLINE @ ,-t ;

: ALIGN-HEADER  ( len -- )      \ make sure link field will be cell aligned
        1+ HERE-t +  DUP ALIGNED  SWAP - ALLOT-t ;

: .WORD   >IN @  BL WORD COUNT DUP 1+ ?CR TYPE SPACE  >IN ! ;

variable last-t

: HEADER   ( -- )
\        CR .S .WORD
        BL WORD ?UPPERCASE COUNT
        HEADS @
        IF      DUP ALIGN-HEADER
                2DUP S,-t                               \ name string
                HERE-t LAST-t !                         \ remember nfa
                DUP C,-t                                \ count byte
                VIEW,                                   \ view field
                THREAD  DUP @  HERE-t ROT !  ,-t        \ link field
        ELSE
                2DROP HEADS ON
        THEN  ;


\ ======================================================================
\ Meta Compiler Create Target Image

VARIABLE TARGET-LINK    \ linked list of TARGET words (for .SYMBOLS)
0 TARGET-LINK !

: DO-TARGET  DOES> MAKE-CODE ;  \ what target words do

: TARGET-CREATE   ( -- )
        >IN @ HEADER >IN !              \ create header in target
        TARGET DEFINITIONS              \ add word to TARGET wordlist
        CREATE
          HERE-T , ( xt )
          HERE TARGET-LINK @ , TARGET-LINK !    \ linked list of target words
        DO-TARGET
        META DEFINITIONS ;

: RECREATE   ( -- )
        >IN @   TARGET-CREATE   >IN !   ;

\ ======================================================================
\ Create target code words

HAVE CLEAR-LABELS 0= [IF]
: CLEAR-LABELS ;
: CHECK-LABELS ;
[THEN]

: INIT-ASSEMBLER  ( -- )        \ prepare for assembly code
        [ ASSEMBLER o] CLEAR-LABELS  SETASSEM o[ META ]
        ASSEMBLER DEFINITIONS  !CSP ;

: CODE   ( -- )
        TARGET-CREATE
        INIT-ASSEMBLER ;

: LABEL   ( -- )
        ALIGN
        INIT-ASSEMBLER   HERE-T CONSTANT  ;

HEX : CALL,  ( t-addr -- )  here-t ad>of &eb000000 or ,-t  ;  DECIMAL

ASSEMBLER DEFINITIONS
: LABEL      A;  HERE-T CONSTANT ;
: END-CODE   A;  IN-META CHECK-LABELS
      o[ ASSEMBLER o]  ?CSP  ;
: C;   END-CODE  ;
META DEFINITIONS

\ ======================================================================
\ Force compilation of target & forward words. We need to reference the
\ special runtime target words like LIT and BRANCH before they are defined,
\ so we store the name of the word and look it up when we need it. Hopefully
\ they will have been defined by then. [TARGET] is for target primatives and
\ [LABEL] is for target assembly labels (runtime of builtin defining words).

: FIND&EXECUTE  ( addr len wordlist -- ? )
        SEARCH-WORDLIST 0= ABORT" Target word not found"  EXECUTE ;

: DEFERED  ( wordlist -- )
        BL WORD COUNT POSTPONE SLITERAL
        POSTPONE LITERAL
        POSTPONE FIND&EXECUTE ;

: [TARGET]  ( -- )  TARGET-WORDLIST    DEFERED ; IMMEDIATE
: [LABEL]   ( -- )  ASSEMBLER-WORDLIST DEFERED ; IMMEDIATE


\ Find the next word in a single wordlist only
: DEFINED-IN  ( wordlist -- xt )
        BL WORD COUNT 2dup upper ROT SEARCH-WORDLIST   0= ?MISSING  ;

: 'T   ( -- xt )   TARGET-WORDLIST  DEFINED-IN ;
: 'F   ( -- xt )   FORWARD-WORDLIST DEFINED-IN ;

: [FORWARD]   ( -- )    'F COMPILE, ;   IMMEDIATE

\ ======================================================================
\ Define transition words, which behave like forth immediate words.

: T:   TRANSITION DEFINITIONS  META  :  ;
: T;   POSTPONE ;  META DEFINITIONS ; IMMEDIATE

: [TRANSITION]  TRANSITION-WORDLIST DEFINED-IN COMPILE, ; IMMEDIATE

T: (   POSTPONE (   T;
T: \   POSTPONE \   T;

: STRING,-T     [CHAR] " PARSE  DUP C,-T  S,-T  0 C,-T  ALIGN  ;

FORWARD: <(.")>
T: ."   [FORWARD]  <(.")>   STRING,-T   T;

FORWARD: <(S")>
T: S"    [FORWARD] <(S")>   STRING,-T   T;

FORWARD: <(ABORT")>
T: ABORT"   [FORWARD] <(ABORT")>    STRING,-T   T;

\ ======================================================================
\ Define target vocabularies (uh, wordlists)

VARIABLE VOC-LINK-T
FORWARD: <VOCABULARY>
: VOCABULARY   ( -- )
        TARGET-CREATE
        [FORWARD] <VOCABULARY>
        here-t cell- dup @-t over ad>of &eb000000 or swap !-t
        #THREADS ,-T
        HERE-T  VOC-LINK-T @ ,-T   VOC-LINK-T !
        #THREADS 0 DO  0 ,-T  LOOP ;
\        512 0 DO  0 ,-T  LOOP ;

: IMMEDIATE   ( -- )
        LAST-t @  DUP C@-t 128 OR  ( Precedence Bit )  SWAP C!-t ;

VARIABLE STATE-T

T: [COMPILE]   'T EXECUTE    T;

: >BODY-T  4 + ;

FORWARD: <(IS)>
T: IS      [FORWARD] <(IS)>    T;
:  IS    'T >BODY @ >BODY-T  2DUP !-T  8 + !-T ;
 ( patches both current and default value of defered word )

\ TO used inside a definition
T: TO   'T >BODY @ ( tcfa )  8 + ,-T  T;
T: +TO  'T >BODY @ ( tcfa ) 12 + ,-T  T;


\ ======================================================================
\ Display the Target Symbol Table

: @COL  _GETXY DROP ;

: TAB   @COL 60 >
        IF  CR  ELSE  20 @COL OVER MOD - SPACES  THEN ;

: .SYMBOLS    ( -- )
        TARGET-LINK
        BEGIN   @ DUP
        WHILE   DUP CELL - ( pfa )
                DUP @ TAB 5 .R SPACE
                BODY> >NAME .ID  ( *SYSDEP* )
                START/STOP
        REPEAT  DROP ;

\ ======================================================================
\ Meta Compiler Resolve Forward References

: .UNRESOLVED   ( -- )
        FORWARD-LINK
        BEGIN   @ DUP
        WHILE   DUP 2 CELLS - RESOLVED? 0=
                IF      DUP 2 CELLS - BODY> >NAME .ID  ( *SYSDEP* )
                THEN
                START/STOP
        REPEAT  DROP ;

: FIND-UNRESOLVED   ( -- cfa f )
        'F    DUP  >BODY RESOLVED?     ;

: RESOLVE   ( taddr cfa -- )
        >BODY   2DUP TRUE OVER CELL+ !   @
        BEGIN   DUP
        WHILE   2DUP @-T   -ROT SWAP
                dup @-t 24 rshift &eb =
                if dup>r rot [ assembler o] br>ad o[ forth ] swap
                  r@ ad>of &eb000000 or r> then !-T
        REPEAT  2DROP  !   ;

: RESOLVES   ( taddr -- )
        FIND-UNRESOLVED
        IF      >NAME .ID ." Already Resolved"   DROP  ( *SYSDEP* )
        ELSE    RESOLVE
        THEN   ;


\ ======================================================================
\ Meta compiler Branching & Looping

T: IF      [TARGET] ?BRANCH  ?>MARK   T;

T: THEN    [TARGET] _THEN    ?>RESOLVE    T;
T: ELSE    [TARGET]  BRANCH  ?>MARK   2SWAP ?>RESOLVE   T;

T: BEGIN   [TARGET] _BEGIN   ?<MARK   T;
T: AGAIN   [TARGET] _AGAIN   ?<RESOLVE   T;
T: UNTIL   [TARGET] _UNTIL   ?<RESOLVE   T;
T: WHILE   [TARGET] _WHILE   ?>MARK  2SWAP  T;
T: REPEAT  [TARGET] _REPEAT  ?<RESOLVE  ?>RESOLVE   T;

T: ?DO     [TARGET] (?DO)    ?>MARK   T;
T: DO      [TARGET] (DO)     ?>MARK   T;
T: LOOP    [TARGET] (LOOP)   2DUP CELL+   ?<RESOLVE   ?>RESOLVE   T;
T: +LOOP   [TARGET] (+LOOP)  2DUP CELL+   ?<RESOLVE   ?>RESOLVE   T;

T: case   [target] _CASE 0 t;
T: of     [target] _OF ?>mark t;
T: endof  [target] _ENDOF ?>mark 2swap ?>resolve rot 1+ t;
T: endcase [target] _ENDCASE 0 ?do ?>resolve loop t;

\ ======================================================================
\ Meta compiler literals

T: LITERAL   ( n -- )   [TARGET] LIT  ,-T   T;
T: [CHAR]    ( -- )     CHAR        [TRANSITION] LITERAL   T;
T: [']       ( -- )     'T >BODY @  [TRANSITION] LITERAL   T;


\ ======================================================================
\ Target EQU is like a constant except that if it is used in a definition
\ it will just compile a literal.

: (EQU)  ( n -- )
        CREATE ,  DOES> @ [TRANSITION] LITERAL ;

: EQU   ( n -<name>- )
        TRANSITION DEFINITIONS
        >IN @  OVER (EQU)  >IN !
        META DEFINITIONS
        CONSTANT ;

: HERE:  ( -<name>- )
        HERE-T
        TRANSITION DEFINITIONS
        >IN @  OVER (EQU)  >IN !
        META DEFINITIONS
        CONSTANT ;

\ ======================================================================
\ Meta compiler defining words

: CREATE  ( -- )
        RECREATE  [LABEL] DOVAR call,
        HERE-T CONSTANT  ;

: LABCREATE  ( -- )
        RECREATE  [LABEL] DOVAR call,
        init-assembler HERE-T CONSTANT  ;

: VARIABLE  ( -- )
        CREATE   0 ,-T   ;

: CONSTANT   ( n -- )
        RECREATE   [LABEL] DOCON call,
        DUP ,-T   CONSTANT   ;

: VALUE  ( n -- )
        TARGET-CREATE
        [LABEL] DOVALUE   call,
        ,-T
        [LABEL] DOVALUE!  call,
        [LABEL] DOVALUE+! call,  ;

: LOCAL  ( n -- )
        TARGET-CREATE
        [LABEL] DOLOCAL  call,
        1+ -4 * ,-T
        [LABEL] DOLOCAL!  call,
        [LABEL] DOLOCAL+! call,  ;

FORTH VARIABLE DEFER-LIST-T META
: DEFER   ( -- )
        TARGET-CREATE   &e51ff004  ,-T
        0 ,-T
        HERE-T  DEFER-LIST-T @ ,-T  DEFER-LIST-T !
        0 ,-T  ;

FORWARD: <(;CODE)>
T: ;CODE   ( -- addr )
        [FORWARD] <(;CODE)>   HERE-T
        STATE-T OFF   IN-META
        INIT-ASSEMBLER T;

T: DOES>     ( -- addr )
        [FORWARD] <(;CODE)>   HERE-T
        &e3ce03ff ,-t \ bic r0, link, # &fc000003
        [LABEL] DODOES CALL,   T;


\ ======================================================================
\ Identify numbers (single numbers only)

: &number? ( ad len -- ad len false | n true )
    over c@ [char] & =
    if 1 /string base @ >r hex
      >number 0= nip nip
      r> base !
    else false
    then  ;

: NUMBER?  ( addr len -- n f )
        OVER C@ [CHAR] - =              \ leading minus sign?
        DUP >R IF  1 /STRING  THEN
        0 0 2SWAP &number? ?dup
        0= if >NUMBER 0= NIP NIP then ( -- u f )
        R> IF SWAP NEGATE SWAP THEN ;

\ ======================================================================
\ Meta Compiler Compiling Loop.

\ We need a special version of WORD that will span multiple lines.
\ This will also save >IN so we can rescan the input stream.
FORTH VARIABLE T-IN META
: TOKEN  ( -- addr )
        BEGIN   >IN @ T-IN !
                BL WORD  DUP C@ 0=
        WHILE   DROP REFILL  0= ABORT" end of file in definition"
        REPEAT  ?UPPERCASE ;

: ]   ( -- )
        STATE-T ON   IN-TRANSITION
        BEGIN   TOKEN FIND
                IF      EXECUTE
                ELSE    COUNT NUMBER?
                        IF      [TRANSITION] LITERAL
                        ELSE    DROP T-IN @ >IN !
                                UNDEFINED ( create forward reference )
                        THEN
                THEN
                STATE-T @ 0=
        UNTIL   ;

T: [   IN-META   STATE-T OFF   T;
T: ;   [TARGET] UNNEST   [TRANSITION] [   T;

\ ======================================================================
\ Interpretive words for Meta

: '   'T >BODY @   ;
: ,   ,-T ;
: C,  C,-T ;
: HERE HERE-T ;
: ALLOT   ALLOT-T  ;
: ,"  STRING,-T ;
: >BODY >BODY-T ;

\ : DIS  ( t-addr -- )  THERE [ DISASSEMBLER ] REST [ META ] ;
\ : DS   ' @-T DIS ;

: :   TARGET-CREATE  [LABEL] DOCOL call,   ]  ;

\ And we're off.....

CR .( Metacompiler Loaded )

\ ======================================================================

CR .( Compiling the KERNEL...) CR

FLOAD fkernel26bit

\ Resolve metacompiler forward references
' (.")          RESOLVES <(.")>
' (S")          RESOLVES <(S")>
' (ABORT")      RESOLVES <(ABORT")>
' (IS)          RESOLVES <(IS)>
' (;CODE)       RESOLVES <(;CODE)>

\ Initialize variables
HERE-T  DP !-T
' FORTH >BODY 2 CELLS +
FORTH-THREADS OVER THERE #THREADS CELLS MOVE
DUP CURRENT !-T
DUP CONTEXT !-T
DUP CONTEXT CELL+ !-T
    VOC>VLINK VOC-LINK !-T              \ setup minimal voc-link for >name
defer-list-t @ defer-list !-t

  CR .( Unresolved references: ) CR   .UNRESOLVED
  CR
  CR .( Host Bytes Free:             )    UNUSED U.
  CR .( First Target Code Address:   )    ORIGIN THERE U.
  CR .( Last Target Code Address:    )    HERE-T THERE U.
  CR .( Target origin:               )    ORIGIN 1 H.R .( h)
  CR .( Target size:                 )    HERE-T ORIGIN - U.

IMAGE HERE-T ORIGIN - TARGET-SAVE kernel26

CR HERE-T ORIGIN - .  .( bytes written to file kernel )

.elapsed