💾 Archived View for stack.tilde.cafe › gemlog › 2022-10-23.Octo.progress.gmi captured on 2024-08-18 at 17:53:22. Gemini links have been rewritten to link to archived content

-=-=-=-=-=-=-

Octo progress, burning out...

I feel a bit burnt out. I had a good month of relatively clear thinking, but feel a bit brainfogged again. Things that were obvious a couple of weeks ago strain my abilities.

A lot of chores are piling up and I will have to travel shortly. So I am trying to wrap up the loose ends in order to avoid losing the thread of this project. I have a dozen (or more?) directories with projects like this sitting abandoned.

Progress

Octo is pretty solid. It has grown beyond a toy, and it's hardly a minimal system even though it's only 2500 bytes of dictionary. Well, to be fair, the table is the same size, and the symbol table is a hair bigger, with 237 symbols defined:

> WORDS
decomp decomp1 deco.lit deco.deref deco.bytes tt2 tt1 bench WORDS THEN ELSE IF WHILE UNTIL AGAIN
BEGIN branch, 0branch, STRLIT-KEY-HANDLER td regs sys _makepr hd.a16 hd.8 hd1 hd hex32sp hex32sp.2
hex32sp.4 dig2 dig4 dig8 hex32 hex16 hex8 dumpfile sys.slot sys.error.msg sys.msg sys.str ALLOT
included MAIN REPL.prompt REPL.step REPL.out REPL.in REPL.debrace state.restore state.save
compile.until compile.one 0c, ; : { ( [ ['] & lit, , w, c, ref, erase.range erase [char]
HASH.PRIME HASH.BASIS PAD.size PAD LINENO BRACEDEPTH PARENDEPTH THELIT LATEST@ LATEST HEAD.ORIGIN
REPL.ptr REPL.buf TRAMP.STRLIT.CHAR SRCBUF.FOFF SRC@ SRC TIB HERE@ HERE DICPTR RUNPTR HAN.SRC.LOG
HAN.SRC HAN.OUT HAN.IN BASE XFP head.source see head.name srcfile.seek src.end.set src.end.get
src.open ' IMMEDIATE head.new .art .src .flag heads.find.code heads.find.hash heads.scan parse
word parse.num parse.neg hash ws SRCBUF.refill \ KEY keyp SRCBUF.reset SRCBUF.clr SRCBUF.get
SRCBUF.put ACCEPT compile.dofixupU8 dot.out . digout digits HEXDIGITS emit cr spaces space 2spaces
tell puts file.open file.open.ro os.ftruncate os.signal os.close os.seek os.open os.read os.write
bye tabe.safemap tabe.wipeup tabe.end tabe.wipemap tabe.map TABEMAP tabe.deref tabe.intern
tabe.find tabe tabe.mask 4dup D+ D- swap2 drop2 dup2 stamp wordlen i case loop do parse.digit
<lambda> Z; NZ; mem.scan ascode regs.prim break 0< 0= < next for bit.reset bit.set bit.test
lzcnt > = push <strU8> strlen lrol <branch> u/mod * _incf4 decf incf *2 /2 rpick DSP / <lit>
<litS16> <litU16> <litS8> <litU8> DOVAR DOCONST one four zero RTOS RSP rfree <0branch> <nzbranch>
xor or and nip - pop drop + CALLSTREAM execute ABORT PROTECT 2x neg c! w! ! 1- 4+ 1+ rot pick
over swap dup w@ c@ dupc@ @ dup@ NOOP.IMM

I can compile code and load files (which can recursively load other files). Many faults are trapped; entering `0 @` actually recovers to the command prompt with an error message and shows where the error was. I can even decompile bytecodes into pretty readable listings:

> 30000911 hd
30000911 F8 F8 F7 FF FE FA FF 00  F6 F6 F5 F5 FD FF FF FD  ⋆⋆⋆⋆⋆⋆⋆⋆⋆⋆⋆⋆⋆⋆⋆⋆
30000921 00 EC C0 20 16 DF BF 7F  11 43 FF FE 2D E2 8B 86  ⋆⋆⋆ ⋆⋆⋆⋆C⋆⋆-⋆⋆⋆
> $3000911 8 decomp
: hd.8
2x
: hd.4
2x 2x dupc@ hex8 space 1+ ;

Look above. The first command is a hexdump of bytecodes at 911. Only the first 8 bytes matter here, up to the 00, which is <RETURN> or `;`.

The second command is a request to decompile 8 bytes, and the result is shown below. Several things are worth considering:

Note the labels`: hd.8` and `: hd.4`. These are just names associated with addresses, and the decompiler picks them up. Labels are valid call targets, and take up no space in the dictionary, so words can fall off from one onto the next: hd.8 continues into hd.4.
; or $00 is simply a <RETURN> token, and does not imply anything about ending a word.
2x simply does whatever follows up to the ; twice. hd.8 does hd.4 twice. hd4 does something 4 times (2x 2x). How? 2x simply pushes the IP (instruction pointer) onto the return stack, so when the rest is done, the token machine gets to do it again. This is often better than setting up a loop.
The first three tokens, the three `2x`s are encoded as F8 F8 F7 ! Amazing, isn't it? That's the sliding window token machine in action. By the time we get to the third one, the indirection table is adjusted one slot up, so what used to be F8 became F7. The lowest slot is retired, and the top slot, FF is made available to the code that follows.
The fourth token happens to be an FF! Yup, it's dupc@, which is the same as `dup c@', but as a single token because it happens a lot and I made a combo routine.

Just out of curiosity, do you want to see the table? Octo has a command `td` to dump the table for a particular address, so let's see:

$30000913 td
30000913 F7 FF FE FA FF 00 F6 F6  F5 F5 FD FF FF FD 00 EC  ⋆⋆⋆⋆⋆⋆⋆⋆⋆⋆⋆⋆⋆⋆⋆⋆
20000914.F7 300000A6 2x
00  300006B6 30000082 30000693 300006C3 300001EE 30000545 300002F0 300006B9  30000536 30000185 3000053A 30000822 300006F6 30000523 3000025C 300006C6 
10  30000658 300006A2 00000000 00000000 00000000 00000000 3000026D 00000000  3000070A 30000705 300002BB 3000013E 300001FE 00000000 300000A1 30000590 
20  30000755 00000000 00000000 00000000 00000000 00000000 00000000 30000310  00000000 00000000 00000000 00000000 300006CB 30000301 30000568 3000071F 
30  3000023D 30000722 300000F5 300001B8 30000518 30000618 30000349 3000057B  00000000 300006E7 30000592 00000000 3000019C 300006DA 300006E4 300002DC 
40  3000060A 3000007C 00000000 300006DF 3000061F 30000620 3000061E 00000000  30000139 00000000 00000000 00000000 300008B8 3000069D 00000000 00000000 
50  00000000 300004A8 300004C3 00000000 300006FB 30000664 00000000 3000036C  300005D0 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
60  00000000 00000000 00000000 00000000 00000000 00000000 00000000 300006B1  00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
70  00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000  00000000 00000000 00000000 00000000 00000000 00000000 30000335 3000052A 
80  30000328 3000035A 300003F2 00000000 3000008E 00000000 300001F8 30000278  00000000 00000000 00000000 00000000 3000072F 30000728 00000000 00000000 
90  30000406 300006F1 300006AC 00000000 00000000 300007C0 300001F3 00000000  00000000 300006EC 00000000 00000000 00000000 00000000 00000000 300007AE 
A0  00000000 00000000 00000000 00000000 00000000 30000622 00000000 00000000  00000000 00000000 00000000 300007B1 00000000 00000000 30000115 00000000 
B0  00000000 00000000 00000000 30000421 30000032 3000065F 300006D0 3000017A  30000445 3000038D 30000467 30000086 30000801 300006D5 300008BF 300003D8 
C0  30000808 30000810 300000FD 30000152 30000194 00000000 00000000 3000081A  3000041C 30000645 30000533 300007D2 00000000 30000510 300007E6 300008C2 
D0  300004D4 300004E0 300004E5 00000000 00000000 00000000 00000000 00000000  00000000 3000010E 30000933 300000C9 30000254 300004C8 00000000 300008F1 
E0  300004AD 300001DD 00000000 3000005B 00000000 300000E9 00000000 30000105  00000000 00000000 00000000 00000000 300001A4 300001E9 300006B6 30000047 
F0  30000700 300004D6 30000143 300008F6 30000223 300008F5 300008F4 300000A6  3000017F 30000134 300004DC 30000911 30000901 30000919 300008E5 30000039

I hope you have a very wide screen to see all 256 entries. Slot $F7 is $300000A6, which is `2x`, as shown above. The table itself is at 20000914. 3000039 is dupc@.

As expected, there are lot's of zeros, because I was very conservative with the sliding table algorithm. It slides one slot for every 4 tokens. The system would work fine with one slot for every 8 tokens, and we would still have zeroes, because a lot of these slots are reused. Remember, all three 2x tokens refer to the same slot! And I'd be surprised if the slot is used in other places as well, as I am fond of 2x.

Ah, it's beautiful to look at.

It's worth it...

Sometimes I wonder why I do this. But then I look at this amazing machine chugging away, constructing these tables and indirecting through them without missing a beat, and it makes me feel good.

I miss Lisp, however. I wish I could figure out a way to apply this tech to a Lisp interpreter, but that seems like a much larger project. Or is it? A simple Lisp metacircular interpreter is only a handful of functions, really. And function application is not that different, I suppose, than what I am doing. Hmm..

index

home