--- /dev/null
+\ Decompilation
+
+: .NAME
+ 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) )
+;
+
+: SEE
+ BL WORD FIND ( find the dictionary entry to decompile )
+
+ CR
+
+ 0= IF
+ ." Word '" COUNT TYPE ." ' not found in dictionary."
+ EXIT
+ THEN
+
+ >LINK
+
+ ( 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 LINK> @ CASE
+ DOCOL OF
+ \ Colon definition
+ [CHAR] : EMIT SPACE DUP 1+ .NAME SPACE
+ DUP ?IMMEDIATE IF ." IMMEDIATE " THEN CR
+ ENDOF
+ DOVAR OF
+ \ Variable definition
+ ." Variable " DUP 1+ .NAME CR
+ 2DROP EXIT
+ ENDOF
+ DOCON OF
+ \ Constant definition
+ ." Constant " DUP 1+ .NAME CR
+ 2DROP EXIT
+ ENDOF
+
+ \ Unknown codeword
+ ." Primitive or word with unrecognized codeword." CR
+ DROP 2DROP EXIT
+ ENDCASE
+
+ 4 SPACES
+
+ LINK> >BODY ( 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"<space> )
+ 1+ DUP @ ( get the length word )
+ SWAP 1+ SWAP ( end start+1 length )
+ 2DUP TYPE ( 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 )
+ >NAME ( and force it to be printed as a dictionary entry )
+ .NAME 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 )
+ >NAME ( look up the codeword to get the dictionary entry )
+ .NAME SPACE ( and print it )
+ ENDCASE
+
+ 1+ ( end start+1 )
+ REPEAT
+
+ [CHAR] ; EMIT CR
+
+ 2DROP ( restore stack )
+;
+
The Lambda Lab / projects / forth.jl.git / blobdiff