X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?a=blobdiff_plain;f=src%2Flib.4th;h=eae7a5dcaf0652a523e5d771bb006c0803293422;hb=bb2da3fd725bbc0672ad7e61fd441434c51da630;hp=781a9667f3848e9b94ec880579fac695e3b323e3;hpb=f767595849002e0e49e1e6f6b0a0c401b09e5c05;p=forth.jl.git diff --git a/src/lib.4th b/src/lib.4th index 781a966..eae7a5d 100644 --- a/src/lib.4th +++ b/src/lib.4th @@ -1,6 +1,6 @@ : / /MOD SWAP DROP ; : MOD /MOD DROP ; -: */ * / ; +: */ -ROT * SWAP / ; : NEGATE 0 SWAP - ; @@ -109,6 +109,14 @@ ; : 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 @ @@ -116,6 +124,8 @@ : I RSP@ 3 - @ ; +: J RSP@ 6 - @ ; + : ?LEAVE IMMEDIATE ' 0BRANCH , 13 , ' R> , ' RDROP , ' RDROP , @@ -130,12 +140,30 @@ ; : +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 @@ -169,16 +197,22 @@ 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. ) @@ -316,3 +350,349 @@ 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" ) + 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 --- " + +