X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?p=forth.jl.git;a=blobdiff_plain;f=src%2Flib.4th;h=955cadfe236e34a1c286d4e98c9f5659b5245676;hp=ea4e7dea202350178b613bb5f70423de06fedf9f;hb=d2b2b3e5b33f882c18c9e7cf8c6623f4e863c2dd;hpb=91c9ee133605d4d8871b897b109a60f401b3aa79 diff --git a/src/lib.4th b/src/lib.4th index ea4e7de..955cadf 100644 --- a/src/lib.4th +++ b/src/lib.4th @@ -1,3 +1,10 @@ +: \ IMMEDIATE + KEY + 10 = 0BRANCH [ -5 , ] +; \ We can now comment! + +\ BASIC DEFINITIONS ---------------------------------------------------------------------- + : / /MOD SWAP DROP ; : MOD /MOD DROP ; : */ -ROT * SWAP / ; @@ -8,26 +15,28 @@ : FALSE 0 ; : NOT 0= ; -: CELLS ; \ Allow for slightly more portable code +\ Translate a number of cells into memory units +\ (in our case 1 cell = 1 memory unit) +: CELLS ; + +\ 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@ @ ; +: C, , ; : DEPTH PSP@ PSP0 @ - ; : '\n' 10 ; : BL 32 ; -: LITERAL IMMEDIATE ' LIT , , ; +: LITERAL IMMEDIATE ['] LIT , , ; -: ':' [ CHAR : ] LITERAL ; -: ';' [ CHAR ; ] LITERAL ; -: '(' [ CHAR ( ] LITERAL ; -: ')' [ CHAR ) ] LITERAL ; -: '<' [ CHAR < ] LITERAL ; -: '>' [ CHAR > ] LITERAL ; -: '"' [ CHAR " ] LITERAL ; -: 'A' [ CHAR A ] LITERAL ; -: '0' [ CHAR 0 ] LITERAL ; -: '-' [ CHAR - ] LITERAL ; -: '.' [ CHAR . ] LITERAL ; +: [CHAR] IMMEDIATE + CHAR + ['] LIT , , +; : CR '\n' emit ; : SPACE BL emit ; @@ -51,7 +60,7 @@ \ CONTROL STRUCTURES ---------------------------------------------------------------------- : IF IMMEDIATE - ' 0BRANCH , \ compile 0BRANCH + ['] 0BRANCH , \ compile 0BRANCH HERE @ \ save location of the offset on the stack 0 , \ compile a dummy offset ; @@ -63,7 +72,7 @@ ; : ELSE IMMEDIATE - ' BRANCH , \ definite branch to just over the false-part + ['] BRANCH , \ definite branch to just over the false-part HERE @ \ save location of the offset on the stack 0 , \ compile a dummy offset SWAP \ now back-fill the original (IF) offset @@ -77,25 +86,25 @@ ; : UNTIL IMMEDIATE - ' 0BRANCH , \ compile 0BRANCH + ['] 0BRANCH , \ compile 0BRANCH HERE @ - \ calculate the offset from the address saved on the stack , \ compile the offset here ; : AGAIN IMMEDIATE - ' BRANCH , \ compile BRANCH + ['] BRANCH , \ compile BRANCH HERE @ - \ calculate the offset back , \ compile the offset here ; : WHILE IMMEDIATE - ' 0BRANCH , \ compile 0BRANCH + ['] 0BRANCH , \ compile 0BRANCH HERE @ \ save location of the offset2 on the stack 0 , \ compile a dummy offset2 ; : REPEAT IMMEDIATE - ' BRANCH , \ compile BRANCH + ['] BRANCH , \ compile BRANCH SWAP \ get the original offset (from BEGIN) HERE @ - , \ and compile it after BRANCH DUP @@ -104,13 +113,21 @@ ; : UNLESS IMMEDIATE - ' NOT , \ compile NOT (to reverse the test) + ['] NOT , \ compile NOT (to reverse the test) [COMPILE] IF \ continue by calling the normal IF ; : DO IMMEDIATE - ' >R , ' >R , - ' LIT , HERE @ 0 , ' >R , + ['] LIT , -1 , [COMPILE] IF + ['] >R , ['] >R , + ['] LIT , HERE @ 0 , ['] >R , + HERE @ +; + +: ?DO IMMEDIATE + ['] 2DUP , ['] - , [COMPILE] IF + ['] >R , ['] >R , + ['] LIT , HERE @ 0 , ['] >R , HERE @ ; @@ -119,43 +136,91 @@ : J RSP@ 6 - @ ; : ?LEAVE IMMEDIATE - ' 0BRANCH , 13 , - ' R> , ' RDROP , ' RDROP , - ' LIT , HERE @ 7 + , ' DUP , ' -ROT , ' - , ' SWAP , ' ! , - ' BRANCH , + ['] 0BRANCH , 13 , + ['] R> , ['] RDROP , ['] RDROP , + ['] LIT , HERE @ 7 + , ['] DUP , ['] -ROT , ['] - , ['] SWAP , ['] ! , + ['] BRANCH , 0 , ; : LEAVE IMMEDIATE - ' LIT , -1 , + ['] LIT , -1 , [COMPILE] ?LEAVE ; : +LOOP IMMEDIATE - ' R> , ' SWAP , ' R> , ' SWAP , ' R> , ' SWAP , ' + , ' 2DUP , ' - , - ' SWAP , ' >R , ' SWAP , ' >R , ' SWAP , ' >R , - ' 0<= , ' 0BRANCH , - HERE @ - , - ' RDROP , ' RDROP , ' RDROP , + ['] DUP , \ Store copy of increment + + ['] R> , ['] SWAP , ['] R> , ['] SWAP , ['] R> , ['] SWAP , ['] + , ['] 2DUP , ['] - , + ['] SWAP , ['] >R , ['] SWAP , ['] >R , ['] SWAP , ['] >R , + + \ 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 - ' LIT , 1 , + ['] LIT , 1 , [COMPILE] +LOOP ; + +\ 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 +; + + \ COMMENTS ---------------------------------------------------------------------- : ( IMMEDIATE 1 \ allowed nested parens by keeping track of depth BEGIN KEY \ read next character - DUP '(' = IF \ open paren? + DUP [CHAR] ( = IF \ open paren? DROP \ drop the open paren 1+ \ depth increases ELSE - ')' = IF \ close paren? + [CHAR] ) = IF \ close paren? 1- \ depth decreases THEN THEN @@ -171,12 +236,22 @@ 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. ) @@ -217,10 +292,10 @@ ( print the remainder ) DUP 10 < IF - '0' ( decimal digits 0..9 ) + [CHAR] 0 ( decimal digits 0..9 ) ELSE 10 - ( hex and beyond digits A..Z ) - 'A' + [CHAR] A THEN + EMIT @@ -273,7 +348,7 @@ SWAP ( u flag ) IF ( was it negative? print the - character ) - '-' EMIT + [CHAR] - EMIT THEN U. @@ -282,7 +357,7 @@ : . 0 .R SPACE ; : .S ( -- ) - '<' EMIT DEPTH U. '>' EMIT SPACE + [CHAR] < EMIT DEPTH U. [CHAR] > EMIT SPACE PSP0 @ 1+ BEGIN DUP PSP@ 2 - <= @@ -314,13 +389,350 @@ THEN ; -: 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 + +( STRINGS ---------------------------------------------------------------------- ) + + +( 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 1+ @ i ! + I @ ( (dest-src) i@ ) + OVER I + ( (dest-src) i@ (dest-src+i) ) + ! ( (dest-src) ) LOOP - SWAP DROP + + 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 [CHAR] " <> + 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 [CHAR] " <> + 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 ( -- ) + [COMPILE] S" ( read the string, and compile LITSTRING, etc. ) + ['] TELL , ( compile the final TELL ) +; + +: .( + KEY DROP + BEGIN + KEY + DUP [CHAR] ) = IF + DROP ( drop the double quote character ) + EXIT ( return from this function ) + THEN + EMIT + AGAIN ; -include ../examples/mandelbrot.4th + +( CONSTANTS AND VARIABLES ------------------------------------------------------ ) + +: CONSTANT + WORD HEADER ( make dictionary entry (the name follows CONSTANT) ) + 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 -- ) + HERE +! ( adds n to HERE, after this the old value of HERE is still on the stack ) +; + +: VARIABLE + CREATE + 1 CELLS ALLOT ( allocate 1 cell of memory, push the pointer to this memory ) +; + + +: VALUE ( n -- ) + WORD HEADER ( 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 +; + +( Fill u ints, starting at a, with the value b ) +: FILL ( a u b -- ) + -ROT OVER + SWAP ?DO + DUP I ! + LOOP + DROP +; + +: ERASE ( a u -- ) + 0 FILL +; + +( 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) + DUP 32 >= OVER 127 <= AND IF + EMIT ( len addr char -- len addr | and print it) + ELSE + BASE @ SWAP HEX + ." \x" 0 .R + BASE ! + THEN + 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! + + +( 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 ) + + DUP >CFA @ CASE + DOCOL OF + \ Colon definition + [CHAR] : EMIT SPACE DUP ID. SPACE + DUP ?IMMEDIATE IF ." IMMEDIATE " THEN CR + ENDOF + DOVAR OF + \ Variable definition + ." Variable " DUP ID. CR + 2DROP EXIT + ENDOF + DOCON OF + \ Constant definition + ." Constant " DUP ID. CR + 2DROP EXIT + ENDOF + + \ Unknown codeword + ." Primitive or word with unrecognized codeword." CR + DROP 2DROP EXIT + ENDCASE + + ( begin the definition with : NAME [IMMEDIATE] ) + ( [CHAR] : EMIT SPACE DUP ID. SPACE + DUP ?IMMEDIATE IF ." IMMEDIATE " THEN CR 4 ) + + 4 SPACES + + >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 EMIT [CHAR] " EMIT SPACE ( print S" ) + 1+ DUP @ ( get the length word ) + SWAP 1+ SWAP ( end start+1 length ) + 2DUP TELL ( print the string ) + [CHAR] " 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 ['] ? ) + ." ['] " + 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 + + [CHAR] ; EMIT CR + + 2DROP ( restore stack ) +; + + +( MEMORY ------------------------------------------------------------------ ) + +: UNUSED ( -- cells ) + MEMSIZE HERE @ - ;