: / /MOD SWAP DROP ;
: MOD /MOD DROP ;
-: */ * / ;
+: */ -ROT * SWAP / ;
: NEGATE 0 SWAP - ;
;
: DO IMMEDIATE
+ ' LIT , -1 , [COMPILE] IF
+ ' >R , ' >R ,
+ ' LIT , HERE @ 0 , ' >R ,
+ HERE @
+;
+
+: ?DO IMMEDIATE
+ ' 2DUP , ' - , [COMPILE] IF
' >R , ' >R ,
' LIT , HERE @ 0 , ' >R ,
HERE @
: I RSP@ 3 - @ ;
+: J RSP@ 6 - @ ;
+
: ?LEAVE IMMEDIATE
' 0BRANCH , 13 ,
' R> , ' RDROP , ' RDROP ,
;
: +LOOP IMMEDIATE
+ ' DUP , \ Store copy of increment
+
' R> , ' SWAP , ' R> , ' SWAP , ' R> , ' SWAP , ' + , ' 2DUP , ' - ,
' SWAP , ' >R , ' SWAP , ' >R , ' SWAP , ' >R ,
- ' 0<= , ' 0BRANCH ,
- HERE @ - ,
+
+ \ Condition differently depending on sign of increment
+ ' SWAP , ' 0>= , [COMPILE] IF
+ ' 0<= ,
+ [COMPILE] ELSE
+ ' 0> ,
+ [COMPILE] THEN
+
+ \ Branch back to begining of loop kernel
+ ' 0BRANCH , HERE @ - ,
+
+ \ Clean up
' RDROP , ' RDROP , ' RDROP ,
+
+ \ Record address of loop end for any LEAVEs to use
HERE @ SWAP !
+
+ [COMPILE] ELSE
+ ' 2DROP , \ Clean up if loop was entirely skipped (?DO)
+ [COMPILE] THEN
;
: LOOP IMMEDIATE
PSP@ SWAP - ( add to the stack pointer )
@ ( and fetch )
;
-
: ROLL ( x_u x_u-1... x_0 u -- x_u-1 ... x_0 x_u )
1+ DUP PICK SWAP ( x_u x_u-1 ... x_0 x_u u+1 )
+ PSP@ 1- SWAP - PSP@ 2- SWAP
+ DO
+ i 1+ @ i !
+ LOOP
+ SWAP DROP
;
( With the looping constructs, we can now write SPACES, which writes n spaces to stdout. )
: SPACES ( n -- )
- 0 DO
- SPACE
- LOOP
+ DUP 0> IF
+ 0 DO SPACE LOOP
+ ELSE
+ DROP
+ THEN
;
( Standard words for manipulating BASE. )
THEN
;
+
+( STRINGS ---------------------------------------------------------------------- )
+
+( Since the smallest unit of memory in our system is 64 bits and since strings
+ are stored as arrays of 64 bit integers, the character store/fetch words are
+ just aliases of the standard store/fetch words. )
+: C! ! ;
+: C@ @ ;
+
+( Block copy, however, is important and novel: )
+: CMOVE ( src dest length -- )
+
+ DUP 0<= IF
+ EXIT
+ THEN
+
+ -ROT OVER - ( length src (dest-src) )
+ -ROT DUP ROT + SWAP ( (dest-src) (src+length) src )
+
+ DO
+ I @ ( (dest-src) i@ )
+ OVER I + ( (dest-src) i@ (dest-src+i) )
+ ! ( (dest-src) )
+ LOOP
+
+ DROP
+;
+
+( C, appends a byte to the current compiled word. )
+: C,
+ HERE @ C!
+ 1 HERE +!
+;
+
+: S" IMMEDIATE ( -- addr len )
+ STATE @ IF ( compiling? )
+ ' LITSTRING , ( compile LITSTRING )
+ HERE @ ( save the address of the length word on the stack )
+ 0 , ( dummy length - we don't know what it is yet )
+ KEY DROP
+ BEGIN
+ KEY ( get next character of the string )
+ DUP '"' <>
+ WHILE
+ C, ( copy character )
+ REPEAT
+ DROP ( drop the double quote character at the end )
+ DUP ( get the saved address of the length word )
+ HERE @ SWAP - ( calculate the length )
+ 1- ( subtract 1 (because we measured from the start of the length word) )
+ SWAP ! ( and back-fill the length location )
+ ELSE ( immediate mode )
+ HERE @ ( get the start address of the temporary space )
+ KEY DROP
+ BEGIN
+ KEY
+ DUP '"' <>
+ WHILE
+ OVER C! ( save next character )
+ 1+ ( increment address )
+ REPEAT
+ DROP ( drop the final " character )
+ HERE @ - ( calculate the length )
+ HERE @ ( push the start address )
+ SWAP ( addr len )
+ THEN
+;
+
+: ." IMMEDIATE ( -- )
+ STATE @ IF ( compiling? )
+ [COMPILE] S" ( read the string, and compile LITSTRING, etc. )
+ ' TELL , ( compile the final TELL )
+ ELSE
+ ( In immediate mode, just read characters and print them until we get
+ to the ending double quote. )
+ KEY DROP
+ BEGIN
+ KEY
+ DUP '"' = IF
+ DROP ( drop the double quote character )
+ EXIT ( return from this function )
+ THEN
+ EMIT
+ AGAIN
+ THEN
+;
+
+( CONSTANTS AND VARIABLES ------------------------------------------------------ )
+
+: CONSTANT
+ WORD ( get the name (the name follows CONSTANT) )
+ CREATE ( make the dictionary entry )
+ DOCOL , ( append DOCOL (the codeword field of this word) )
+ ' LIT , ( append the codeword LIT )
+\ , ( append the value on the top of the stack )
+ ' EXIT , ( append the codeword EXIT )
+;
+
+: ALLOT ( n -- addr )
+ HERE @ SWAP ( here n )
+ HERE +! ( adds n to HERE, after this the old value of HERE is still on the stack )
+;
+
+: VARIABLE
+ 1 CELLS ALLOT ( allocate 1 cell of memory, push the pointer to this memory )
+ WORD CREATE ( make the dictionary entry (the name follows VARIABLE) )
+ DOCOL , ( append DOCOL (the codeword field of this word) )
+ ' LIT , ( append the codeword LIT )
+ , ( append the pointer to the new memory )
+ ' EXIT , ( append the codeword EXIT )
+;
+
+
+: VALUE ( n -- )
+ WORD CREATE ( make the dictionary entry (the name follows VALUE) )
+ DOCOL , ( append DOCOL )
+ ' LIT , ( append the codeword LIT )
+ , ( append the initial value )
+ ' EXIT , ( append the codeword EXIT )
+;
+
+: TO IMMEDIATE ( n -- )
+ WORD ( get the name of the value )
+ FIND ( look it up in the dictionary )
+ >DFA ( get a pointer to the first data field (the 'LIT') )
+ 1+ ( increment to point at the value )
+ STATE @ IF ( compiling? )
+ ' LIT , ( compile LIT )
+ , ( compile the address of the value )
+ ' ! , ( compile ! )
+ ELSE ( immediate mode )
+ ! ( update it straightaway )
+ THEN
+;
+
+( x +TO VAL adds x to VAL )
+: +TO IMMEDIATE
+ WORD ( get the name of the value )
+ FIND ( look it up in the dictionary )
+ >DFA ( get a pointer to the first data field (the 'LIT') )
+ 1+ ( increment to point at the value )
+ STATE @ IF ( compiling? )
+ ' LIT , ( compile LIT )
+ , ( compile the address of the value )
+ ' +! , ( compile +! )
+ ELSE ( immediate mode )
+ +! ( update it straightaway )
+ THEN
+;
+
+
+( PRINTING THE DICTIONARY ------------------------------------------------------ )
+
+: ID.
+ 1+ ( skip over the link pointer )
+ DUP @ ( get the flags/length byte )
+ F_LENMASK AND ( mask out the flags - just want the length )
+
+ BEGIN
+ DUP 0> ( length > 0? )
+ WHILE
+ SWAP 1+ ( addr len -- len addr+1 )
+ DUP @ ( len addr -- len addr char | get the next character)
+ EMIT ( len addr char -- len addr | and print it)
+ SWAP 1- ( len addr -- addr len-1 | subtract one from length )
+ REPEAT
+ 2DROP ( len addr -- )
+;
+
+: ?HIDDEN
+ 1+ ( skip over the link pointer )
+ @ ( get the flags/length byte )
+ F_HIDDEN AND ( mask the F_HIDDEN flag and return it (as a truth value) )
+;
+: ?IMMEDIATE
+ 1+ ( skip over the link pointer )
+ @ ( get the flags/length byte )
+ F_IMMED AND ( mask the F_IMMED flag and return it (as a truth value) )
+;
+
+: WORDS
+ LATEST @ ( start at LATEST dictionary entry )
+ BEGIN
+ ?DUP ( while link pointer is not null )
+ WHILE
+ DUP ?HIDDEN NOT IF ( ignore hidden words )
+ DUP ID. ( but if not hidden, print the word )
+ SPACE
+ THEN
+ @ ( dereference the link pointer - go to previous word )
+ REPEAT
+ CR
+;
+
+( FORGET ---------------------------------------------------------------------- )
+
+: FORGET
+ WORD FIND ( find the word, gets the dictionary entry address )
+ DUP @ LATEST ! ( set LATEST to point to the previous word )
+ HERE ! ( and store HERE with the dictionary address )
+;
+
+( DUMP ------------------------------------------------------------------------ )
+
+\ TODO!
+
+( CASE ------------------------------------------------------------------------ )
+
+: CASE IMMEDIATE
+ 0 ( push 0 to mark the bottom of the stack )
+;
+
+: OF IMMEDIATE
+ ' OVER , ( compile OVER )
+ ' = , ( compile = )
+ [COMPILE] IF ( compile IF )
+ ' DROP , ( compile DROP )
+;
+
+: ENDOF IMMEDIATE
+ [COMPILE] ELSE ( ENDOF is the same as ELSE )
+;
+
+: ENDCASE IMMEDIATE
+ ' DROP , ( compile DROP )
+
+ ( keep compiling THEN until we get to our zero marker )
+ BEGIN
+ ?DUP
+ WHILE
+ [COMPILE] THEN
+ REPEAT
+;
+
+
+( DECOMPILER ------------------------------------------------------------------ )
+
+: CFA>
+ LATEST @ ( start at LATEST dictionary entry )
+ BEGIN
+ ?DUP ( while link pointer is not null )
+ WHILE
+ 2DUP SWAP ( cfa curr curr cfa )
+ < IF ( current dictionary entry < cfa? )
+ NIP ( leave curr dictionary entry on the stack )
+ EXIT
+ THEN
+ @ ( follow link pointer back )
+ REPEAT
+ DROP ( restore stack )
+ 0 ( sorry, nothing found )
+;
+
+: SEE
+ WORD FIND ( find the dictionary entry to decompile )
+
+ ( Now we search again, looking for the next word in the dictionary. This gives us
+ the length of the word that we will be decompiling. (Well, mostly it does). )
+ HERE @ ( address of the end of the last compiled word )
+ LATEST @ ( word last curr )
+ BEGIN
+ 2 PICK ( word last curr word )
+ OVER ( word last curr word curr )
+ <> ( word last curr word<>curr? )
+ WHILE ( word last curr )
+ NIP ( word curr )
+ DUP @ ( word curr prev (which becomes: word last curr) )
+ REPEAT
+
+ DROP ( at this point, the stack is: start-of-word end-of-word )
+ SWAP ( end-of-word start-of-word )
+
+ ( begin the definition with : NAME [IMMEDIATE] )
+ ':' EMIT SPACE DUP ID. SPACE
+ DUP ?IMMEDIATE IF ." IMMEDIATE " THEN
+
+ >DFA ( get the data address, ie. points after DOCOL | end-of-word start-of-data )
+
+ ( now we start decompiling until we hit the end of the word )
+ BEGIN ( end start )
+ 2DUP >
+ WHILE
+ DUP @ ( end start codeword )
+
+ CASE
+ ' LIT OF ( is it LIT ? )
+ 1+ DUP @ ( get next word which is the integer constant )
+ . ( and print it )
+ ENDOF
+ ' LITSTRING OF ( is it LITSTRING ? )
+ [ CHAR S ] LITERAL EMIT '"' EMIT SPACE ( print S"<space> )
+ 1+ DUP @ ( get the length word )
+ SWAP 1+ SWAP ( end start+1 length )
+ 2DUP TELL ( print the string )
+ '"' EMIT SPACE ( finish the string with a final quote )
+ + ( end start+1+len, aligned )
+ 1- ( because we're about to add 4 below )
+ ENDOF
+ ' 0BRANCH OF ( is it 0BRANCH ? )
+ ." 0BRANCH ( "
+ 1+ DUP @ ( print the offset )
+ .
+ ." ) "
+ ENDOF
+ ' BRANCH OF ( is it BRANCH ? )
+ ." BRANCH ( "
+ 1+ DUP @ ( print the offset )
+ .
+ ." ) "
+ ENDOF
+ ' ' OF ( is it ' (TICK) ? )
+ [ CHAR ' ] LITERAL EMIT SPACE
+ 1+ DUP @ ( get the next codeword )
+ CFA> ( and force it to be printed as a dictionary entry )
+ ID. SPACE
+ ENDOF
+ ' EXIT OF ( is it EXIT? )
+ ( We expect the last word to be EXIT, and if it is then we don't print it
+ because EXIT is normally implied by ;. EXIT can also appear in the middle
+ of words, and then it needs to be printed. )
+ 2DUP ( end start end start )
+ 1+ ( end start end start+1 )
+ <> IF ( end start | we're not at the end )
+ ." EXIT "
+ THEN
+ ENDOF
+ ( default case: )
+ DUP ( in the default case we always need to DUP before using )
+ CFA> ( look up the codeword to get the dictionary entry )
+ ID. SPACE ( and print it )
+ ENDCASE
+
+ 1+ ( end start+1 )
+ REPEAT
+
+ ';' EMIT CR
+
+ 2DROP ( restore stack )
+;
+
+
+( WELCOME MESSAGE ------------------------------------------------------------- )
+
+CR CR ." --- TimForth initialized --- "
+
+
The Lambda Lab / projects / forth.jl.git / blobdiff