ENGINE.md step 2, the carrier. Ruled 2026-10-05 (V3-PARITY.md 1i), on
DECOMPOSITION.md section 6: a write to a port blocks until the neighbour
reads.
- node: v4_node_port_attach, v4_node_port_served; a store to the port keeps
the value as the request and blocks the node
- exec: a blocked node executes nothing; served, it goes on from the opcode
after the store, in the same instruction word; a fault meanwhile abandons
the rest of the word
- compile.v4: n KERNEL-WORD name makes a word whose body writes n to the
port; its arguments and results are on the data stack
- boot: the kernel's words are made by handing the node text, and requests
are served between the node's opcodes; one no one serves is error 12
- BYE, the first kernel word: hosted it leaves the program, as hosted v3;
on the lone node it is v3's cold restart
- ENGINE.md 3a: multiuser, multitasking, preemptive and cooperative, and
what that asks of the engine
Verified: make -C v4 test passes at both widths, with tests/test_port.c;
hosted-check passes on three ISAs; clean qemu with STARFORTH_V4=1 on amd64,
aarch64 and riscv64 passes POST with the same hashes as hosted, and a
kernel word no one serves and BYE typed at each prompt are answered
(logs/20261005-185506, -185734, -190101; -185234 is an amd64 run in which
those two lines were not typed).
Not done: v3's own C functions serving a node.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A v4 node no longer reads its own command line or prints a prompt. Its
host puts a line of text in the node's input buffer and starts it at
(LINE); the node interprets it and stops at (IDLE), leaving in
(LINE-STATUS) how it ended: completed, an error, or QUIT. The host says
" ok" or " ERROR" and prompts, as the kernel's REPL does for a v3 VM. A
line may be 1024 characters, a block, as v3's. Ruled 2026-10-05
(V3-PARITY.md 1b); design ENGINE.md 3.1.
- quit.v4: (REPL), the node's prompt loop, is gone; (LINE) (IDLE) (DONE)
- image.h/.c: v4_line_begin, v4_line_done, v4_line_status; the node is
idle at switch-on
- boot.c: v4_boot_line, the one loop the hosted binary, the kernel and the
capsule loader hand a line with; the code that took " ok" and the prompt
back out of the node's output is gone
- hosted.c, sk_v4.c: the prompt and the line editing are the host's
- test_host_quit.c: the tests are the node's host; two tests of the old
80-character prompt line now test a whole line, 1024 and 1025 characters
Verified: make -C v4 test passes at both widths; hosted-check passes on
three ISAs; clean qemu with STARFORTH_V4=1 on amd64, aarch64 and riscv64
passes POST (550 of 550) with the same hashes as hosted, and three lines
typed at each bare-metal prompt through the serial port are answered
correctly (logs/20261005-180922, -181152, -181541).
Still the lone node: kernel_main.c starts it before the fleet tables.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
(CATCH): while it is not zero, a line that ends in an error sets it to -1
and ends " ok" instead of " ERROR". (EMIT-HOOK): the xt of a word that is
given each character EMIT would send to the console. The prompt loop sets
(EMIT-HOOK) to 0 at the end of every line. docs/v4.0.0/NUCLEUS.md 6.3,
amended: it said one nucleus word would do.
Verified: make -C v4 test passes at both widths; by hand at the hosted
prompt, an unknown word and a division by zero are caught, the output hook
receives every character, and an uncaught error still says ERROR.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- Each entry's flags cell also holds v3's four fields: denied, pinned,
mode and a 16-bit TTL.
- compile.v4: INTERPRET checks every word it is about to execute or
compile -- recheck at TTL 0, else count down; a denied word is refused
with v3's line, the stack emptied and the line ended.
- capsule/acl.v4: ACL-MODE@ ACL-MODE! ACL-TTL@ ACL-TTL! ACL-ALLOW@
ACL-ALLOW! ACL-PINNED? ACL-PIN ACL-INHERIT ACL-INIT-PRIMITIVES ACL-HEAT@
ACL-WORD-ID, and ACL-HOOK.
- capsule/ACL.fth: v3's ACL.4th as FORTH source the node compiles; loading
it switches access control on.
- v3 checks every execution, inside definitions too. v4's code is native,
so it checks a word when it is compiled as well as when interpreted; a
call compiled while the word was allowed is not checked again.
DECOMPOSITION.md 5.20 says so.
- ACL-HEAT@ is 0 until heat is readable (D-6).
- tests/test_host_quit.c: seven transcripts of the v3 binary; the policy
file loaded and exercised; COLD.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- capsule/log.v4: the level constants LOG-ERROR .. LOG-DEBUG, LOG-LEVEL!
and LOG-LEVEL@, LOG-ERROR" .. LOG-DEBUG" and LOG-ERROR-STR ..
LOG-DEBUG-STR. A message is printed if its level is at or below
LOG-LEVEL, as v3's line -- colour, level, text -- without the time of
day, which a node has not got.
- LOG-xxx" compiles like ." : the level, a call to (LOG"), the text. SEE
shows it as text. COLD puts LOG-LEVEL back to LOG-INFO.
- tests/test_host_quit.c: ten transcripts of the v3 binary, every level
at every setting.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- capsule/tools.fth: SEE as FORTH source the node compiles itself. v4
code is native, so it shows each instruction word of a definition: the
opcodes by name, literals' values, the names of the words called or
jumped to, and text compiled by ." S" and ABORT" as text. A data word
shows what it holds; an immediate word says so.
- quit.v4: the three string run-time words get names, compile-only, so
that SEE can tell text from code.
- tests/test_host_quit.c: definitions with literals, text, IF and loops;
the capsule's own words; SEE shown by SEE.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- capsule/editor.fth: the block editor as FORTH source, which the node
compiles itself. It is a vocabulary, EDITOR, used at the ordinary
prompt: n EDIT, then L N B T P E D S H R I WIPE DONE. v3's EDIT, a
shell of its own, is not carried over (ruled 2026-10-05); v3's L S and
SHOW are kept in FORTH as they were, with COPY.
- system.v4: COLD (the system as the loader left it), WARM, PAGE,
VERSION, 79-STANDARD (FORTH-79: silent), and DEFER IS DEFER@ as v3.
- input.v4: where words are split at blanks a zero byte reads as a blank,
so a block never written, or filled a line at a time, loads cleanly.
- tests/test_host_quit.c: the editor's source fed to the prompt line by
line, every command on empty and full screens, what reaches storage;
the system words; deferred words.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- The golden model's host node gets a block storage device: four
memory-mapped registers (number, address, command, status), 1024-byte
blocks as 256 cells. tests/test_node.c.
- capsule/blocks.v4: BLOCK BUFFER UPDATE SAVE-BUFFERS EMPTY-BUFFERS LIST
LOAD SCR BLK (FORTH-79) and v3's FLUSH THRU and -->, over two buffers.
- The text being interpreted is at the address in (SRC), which QUERY makes
the terminal's buffer and LOAD a block's; LOAD saves and restores it, so
blocks nest and the rest of LOAD's line runs afterwards. WORD makes
sure a loading block is still in a buffer before it reads.
- In a block, \ skips to the next 64-character line.
- A block number that does not exist, and --> at the terminal, are errors
with messages (D-18).
- tests/test_host_quit.c: ten transcripts of the v3 binary; nesting three
deep on two buffers; what reaches the device and when.
v3's LOAD drops the rest of its line, and v3 has no BLK.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- VOCABULARY DEFINITIONS CONTEXT CURRENT FORTH, and v3's ORDER. A name is
looked up in the CONTEXT vocabulary and then in FORTH; a new entry goes
into the CURRENT vocabulary; : makes the CURRENT vocabulary CONTEXT;
FORTH is immediate.
- WORDS lists the CONTEXT vocabulary. FORGET takes what was defined later
out of every vocabulary, and a vocabulary that goes gives way to FORTH.
- v3's vocabularies separate nothing: a word defined in one is found from
every other, and one redefined in a vocabulary replaces FORTH's for good.
- tests/test_host_quit.c: isolation, chaining to FORTH, two vocabularies
with the same names, FORGET across them; and DUMP is now checked to put
BASE back.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- capsule/qmath.v4: Q.FROM-INT Q.TO-INT Q.1 Q.0 Q.SCALE Q.+ Q.- Q.* Q./
Q.ABS Q.NEG Q.= Q.< Q.> Q.0= Q.MAX Q.MIN Q.EXP Q.SQRT Q.LOG Q.SIN Q.COS
Q.PRINT -- the definitions test_foundation.c executes on the mesh node,
now in the host node's vocabulary.
- numout.v4: DUMP.
- Q./ by zero, and Q.SQRT and Q.LOG outside their domain, leave the
result D-11 and D-12 give and then raise an error (D-18): "Division by
zero", "Argument out of range". v3 returns 0 silently.
- tests/test_host_quit.c: 122 results printed by Q.PRINT are transcripts
of the v3 binary, the same at both cell widths; signed values, the
errors and DUMP's layout besides.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- compile.v4: CASE OF ENDOF ENDCASE, as v3 (they nest; a word out of
place is a control structure mismatch); ['] and [LITERAL].
- quit.v4: S" and its run-time word; at the prompt the text is copied to
PAD.
- capsule/system.v4: WORDS and VLIST; FORGET (FORTH-79), which gives the
space back and will not remove a word below FENCE -- the capsule's own
words -- where v3's FORGET DUP succeeds.
- tests/test_host_quit.c: ten more transcripts of the v3 binary, and
nesting, the fence and the listing.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
capsule/words.v4: the stack, comparison, shift, double, mixed and string
words whose definitions DECOMPOSITION.md already gives and the mesh-node
tests execute, now in the host node's vocabulary:
2SWAP 2OVER 2ROT 2>R 2R> 2R@ 2@ 2! -! 0<> 0> <> <= >= U< U> ABS MAX MIN
WITHIN LSHIFT RSHIFT D- DABS D0= D0< D= D2* D2/ D< DMAX DMIN M+ M-
CMOVE> MOVE FILL ERASE BLANK -TRAILING COMPARE SEARCH SCAN SKIP
?TERMINAL TRUE FALSE INVERT NOP
- A shift count that is negative or as large as the cell is an error, as
in v3 (code 9, "Shift count out of range").
- tests/test_host_quit.c: 36 sessions from the prompt that are
transcripts of the v3 binary, and the cases where v4 keeps the standard
(MOVE in cells; M+ and M- with the double low cell first).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Ruled 2026-10-04: guard all errors. The errors that set NODE-ERROR and
let the line run on now stop it at once, with a message.
- A store of a non-zero code to NODE-ERROR is a trap, a sixth kind of
fault: nothing after it executes, the return stack is emptied, and the
data stack is left as the word left it. Not attached, NODE-ERROR is
plain memory, as the tests below the prompt use it.
- The capsule's words store a code where they stored -1, and the prompt's
(RAISED) prints its message: Negative count, Not a number, Number too
long, Not a character, Dictionary full, Name missing, Control structure
mismatch, Control structures too deep.
- ' and COMPILE and [COMPILE] of a word that is not there say
UNKNOWN WORD: 'xxx', as the interpreter does.
- tests: the trap in test_exec.c; every message from the prompt, with the
rest of the line not run and the stack kept, in test_host_quit.c.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- capsule/numout.v4: <# # #S HOLD SIGN #>, . .R U. U.R D. D.R, ?, SPACES,
DECIMAL HEX OCTAL -- the definitions DECOMPOSITION.md 5.8 gives and the
mesh-node tests execute, now words of the host node's vocabulary.
- .S, which D-16 makes possible again: as v3, the depth, then every value
from the deepest, then a new line. It needs six cells of the stack
free.
- tests/test_host_quit.c: printed from the prompt, with 14 more sessions
that are transcripts of the v3 binary, and the ends of the number range
at each cell width.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
With the stacks counted and guarded (D-16) their size is a parameter of
the node. The host node, which runs the interpreter and the compiler
under the user's programme, gets 32 values and 32 return entries; a mesh
node keeps the F18's 10 and 9. Nothing else about the mechanism or any
word's definition changes.
- stack.h: V4_DATA_RING and V4_RET_RING are build parameters; the
Makefile sets them for the host-node tests.
- tests/test_host_quit.c no longer assumes a size: it fills the stacks to
whatever they are, and takes every exit with the return stack full.
- Measured on the host node now: 28 values on a line, 29 waiting between
lines, words 31 deep from the prompt.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Ruled 2026-10-04, revising D-2: stack overflow and underflow are errors
that are shown and return to the prompt, not silent wrap-around.
- Each stack counts what it holds. Before every opcode the executor
checks that the stacks hold what it takes and have room for what it
leaves; otherwise the opcode does nothing and the node faults, as for a
bad address, to that kind's handler. Every fault empties both stacks.
- The fault handler is now a table of five jumps: address, data overflow,
data underflow, return overflow, return underflow. The host node says
"Stack overflow", "Stack underflow", "Return stack overflow",
"Return stack underflow", then ERROR and the prompt.
- Two registers, DSTACK-DEPTH and RSTACK-DEPTH: a fetch reads the depth,
a store empties the stack. QUIT, ABORT and the error exits empty the
return stack before they call anything; ABORT empties the data stack.
- capsule/forth.v4: DEPTH, PICK and ROLL, to FORTH-79 (counting from
one). PICK and ROLL set the values above the one wanted aside in
memory, and work with the stack full.
- Division by zero now takes its operands off the stack, as v3 does.
- A colon with no room for its entry abandons the line.
- tests: every opcode at every depth of both stacks; the faults, the
registers and the three words from the prompt.
The sizes are unchanged: ten values, nine return entries.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Ruled 2026-10-04: guarded, an error shown, back to the prompt.
- capsule/forth.v4: / MOD /MOD */ */MOD M/MOD, M* and S>D join the
vocabulary. Each dividing word tests its divisor first; zero prints
v3's message ("/: Division by zero"), ends an open definition, prints
ERROR and returns to the prompt from however deep.
- SM/REM here has UM/MOD written into it and keeps its signs in memory,
and */MOD has M* written in, so that division can be used inside words
that other words call: / from four words deep, */MOD from three.
- forth.v4 now loads after quit.v4, which the guard leaves through.
- tests: v3 transcripts for each message; /MOD, /, MOD and */MOD against
C on every pair of edge values.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Ruled 2026-10-04: guarded, an error shown, back to the prompt.
- The executor checks every address a programme uses (P, A, B) before
using it. Outside memory the opcode does nothing, the rest of its word
is not executed, and P becomes the node's fault handler; a node with no
handler stops. v4_node_load/store never index outside memory.
- capsule/quit.v4: (FAULT), the host node's handler, prints
"Address out of range", ends an open definition, prints ERROR and
returns to the prompt.
- tests: every memory opcode and P in test_exec.c; from the prompt, from
inside nested words and loops, in test_host_quit.c.
This closes the hole node.h described: a wild address used to index the
model's own memory gigabytes out of bounds.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Layer 5 of the compiler capsule. The host node is now started at QUIT and
left running: it prompts, reads a line from its console with QUERY,
interprets it, says " ok" or " ERROR", and goes round again.
- capsule/quit.v4: QUIT and ABORT (FORTH-79), ABORT" and (ABORT") as v3 has
them, ." and (.") (FORTH-79). Text is compiled as a counted string after
the call; the run-time word returns to the cell after it.
- INTERPRET prints v3's messages before abandoning a line:
UNKNOWN WORD: 'xxx' and xxx: compile-only.
- core.v4: CR SPACE COUNT TYPE, as DECOMPOSITION.md gives them.
- input.v4: WORD split so that (PARSE) can take text without skipping
leading delimiters (." " is an empty string); EXPECT keeps its place in
memory, so six values may wait on the stack while a line is typed.
- tests/test_host_quit.c: the node is fed characters and its output read;
16 sessions are transcripts of the v3 binary.
QUIT stops the line from inside any word and says nothing; v3's goes on
with the line and cannot be compiled. v3's compiled ABORT" crashes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Measured, compiling a DO loop left one return entry spare under
INTERPRET and a defining word called from inside another word
overflowed the nine-entry return stack (D-2); the prompt loop will take
one more.
C@ and C! shift without a loop. The code generator shifts each opcode
into the word being built, so nothing is placed by a counted shift, and
the address masks come from a table. The dictionary search, the
in-liner, the end of a loop and the making of a data word are each one
word reached by a jump.
Every kind of line now leaves at least three return entries spare while
it compiles; a word run from the interpreter has six; and CREATE ...
DOES> works from the prompt, from a word, and from a word that calls
that.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The fourth layer of the compiler capsule. compile.v4: INTERPRET's
loop, STATE [ ] : ; EXIT IMMEDIATE LITERAL COMPILE [COMPILE] ' EXECUTE,
CREATE VARIABLE CONSTANT DOES>, and IF ELSE THEN BEGIN UNTIL AGAIN
WHILE REPEAT DO ?DO LOOP +LOOP on a control-flow stack in memory.
forth.v4: the first words of the vocabulary, the in-line ones.
FORTH source now goes in and running code comes out. 49 programmes
were run through the v3 binary and through this; every result agrees,
bar COMPILE, which v3 cannot run. The code laid down for each control
structure is word for word the expansion DECOMPOSITION.md gives.
A line may have six values on the stack while it is interpreted, and
words called from the interpreter may nest eight deep.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
WORD, the dictionary words and the code generator run underneath
whatever the user has on the stacks, which are ten and nine deep (D-2).
Measured, they used five to seven data cells of their own, leaving a
line about three. Each now keeps what it works on in its file's
scratch cells and has at most three cells on the data stack; , calls
nothing; and the longest chains of calls are shorter.
The public words of core.v4, input.v4 and dict.v4 get dictionary
headers. NUMBER is split so the interpreter can have a flag instead of
NODE-ERROR. The host-node tests share one memory map, host_map.h.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
&NAME is the address of a word as a literal; CONST+N is a loader
constant plus an offset as one literal, so that a capsule file can
address the cells of its scratch area without adding at run time.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
'header NAME [flags]' in front of a word gives it a dictionary entry in
the layout capsule/dict.v4 uses, linked to the header before it, so the
words of a capsule are in the dictionary as soon as it is assembled.
The name is taken as it stands (it may be ( or + or ;) and the
assembler's own name for the code may differ.
Tested in the assembler's own test, and by FIND and the field words
running over assembler-made entries beside ones (HEADER) made.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The third layer of the compiler capsule, v4/capsule/codegen.v4: opcodes,
literals and branches packed into instruction words at HERE, by the
rules of sections 1.2 and 2. (OP,) (LIT,) (LABEL) (BRANCH,) (JUMP,)
(CALL,) (BRANCH>) (RESOLVE) (FLUSH) (CG-RESET).
Tested by laying the same programmes down with the text assembler on
one node and with the code generator, running, on another, and
comparing memory word for word: every opcode, literals and branches in
every slot position, and 600 random programmes. What it lays down is
then run.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The second layer of the compiler capsule, v4/capsule/dict.v4: HERE ALIGN
ALLOT , C, 2, PAD LATEST; an entry layout reached entirely from the xt,
with >LINK LFA LINK> >NAME NFA NAME> CFA PFA >BODY TRAVERSE SMUDGE
HIDDEN on it; and FIND and ' .
FIND is FORTH-79's and v3's. ' is FORTH-79's: the parameter field
address, which for a code word is what FIND gives. ALLOT counts cells
(D-1). 31 characters of a name are significant.
Executed at both cell widths against a list of 300 entries kept in C.
WORD no longer holds its length on the return stack.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
FORTH-79's reference .R right-justifies the number in its field and
prints nothing after it; v3 printed a space. . U. and D. still print
their one space.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
MOVE moves n cells, the cell at addr1 first, and nothing for n <= 0.
v3's moved bytes like memmove; CMOVE and CMOVE> do that.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
LEAVE sets the limit equal to the index: the rest of the body runs with
the index unchanged and the loop ends at the next LOOP or +LOOP. v3's
left the loop at once, which is FORTH-83's.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Ruled 2026-10-04: standard words follow the standard where v3 did not.
EXPECT takes up to n characters (v3 took n-1) and does nothing for
n <= 0. QUERY takes up to 80 (v3: 1024). WORD stores the delimiter it
met, or a zero at the end of the text, after the word, and leaves >IN
just past that one delimiter (v3 skipped them all and stored a zero);
the word may be up to 255 characters (v3: 62).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The first layer of the compiler capsule, on the host node: TIB >IN SPAN
SOURCE BL EXPECT QUERY WORD ENCLOSE CONVERT NUMBER and the comment
words. The definitions are text, v4/capsule/core.v4 (the core words
they rest on) and v4/capsule/input.v4, assembled by the text assembler,
which can now read a file.
EXPECT, QUERY, WORD and ENCLOSE behave as v3's. CONVERT and NUMBER are
FORTH-79 (ruled 2026-10-04): any BASE, a double in the standard order,
and NUMBER returns a signed double or sets NODE-ERROR.
Executed at both cell widths against C and against values recorded from
the v3 binary.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Node memory is a build parameter. Tests named test_host_*.c are now
built with V4_NODE_WORDS=16384, the host node that will hold the
compiler, the dictionary and the text being compiled; every other test
keeps the 1024-word mesh node.
The first such test checks the node at that size and the text
assembler's branch placement, which only matters there: a branch slot
that cannot reach the whole node is not used.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Test support, beside the slot packer: reads definitions in the notation
DECOMPOSITION.md uses -- words, opcodes, literals, constants, labels,
branches, FOR NEXT and FOR UNEXT, in-line macros, comments -- and lays
them down through the slot packer, so they no longer have to be retyped
opcode by opcode in C.
Tested by assembling SWAP, UM/MOD, C@ and C! both ways on two nodes and
comparing memory word for word, by running what is assembled, and on
every error it reports, each with its line number.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
?TERMINAL reads CONSOLE-STATUS; KEY polls it until a character is
pending and then takes it from CONSOLE-RX. Executed on the golden
model at both cell widths, including a transcript of the v3 binary, and
KEY shown still waiting after 5000 instruction words with no input.
v3's KEY returned -1 at the end of its input; here KEY waits.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The console's receive side, standing in for the console node until the
mesh exists, as CONSOLE-TX does for output. A data fetch (@, @+, @b)
from CONSOLE-STATUS gives -1 when a character is pending and 0 when
not; from CONSOLE-RX it gives the next character and takes it, or -1
with none pending. The characters come from a queue the test feeds.
Instruction words and literals are still fetched with v4_node_load, so
code at a register's address is never taken for the register.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
(DO) (?DO) (LOOP) (+LOOP) (LEAVE) I J UNLOOP and (0BRANCH), laid down
in line by hand as the compiler will, executed on the golden model at
both cell widths against C on every pair of 14 loop ends and 11 steps,
and against sequences recorded from the v3 binary.
(LOOP) goes round again while index < limit, signed, as v3 does; the
document's equality test differed whenever start >= limit. (+LOOP) is
now specified. J keeps the outer index in A and needs no extra return
entry.
LEAVE discards the limit and index. v3 left them on its return stack,
which made a LEAVE in an inner loop stop the outer one.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
M- M* M/MOD MOD */ */MOD, D0< D2* D2/ 2ROT, 2DROP and 2>R 2R@ 2R>,
beside UM* and SM/REM in test_foundation.c. Executed on the golden
model at both cell widths against C and results recorded from the v3
binary.
M- widens n before negating it, so the most negative n is right.
*/MOD goes through a full double product. D2/ is one +* step.
M- and M/MOD take the double in the standard order ( lo hi ), as M+
does; v3 took its low cell on top.
The foundation test's node is now full: 958 of the 960 words below its
variables.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
NIP SWAP ROT -ROT ?DUP 2DUP, >R R@ R>, @ ! +! -! 2@ 2! CELLS,
- NEGATE 1+ 1- 2+ 2- MIN MAX, OR NOT 0= 0< 0<> 0> = <> < > <= >= U<
WITHIN TRUE FALSE in a new test, and * and / beside UM* and /MOD in
test_foundation.c. Executed on the golden model at both cell widths
against C on every combination of the edge values and against recorded
transcripts of the v3 binary.
WITHIN is low <= n < high with signed comparisons, which is what v3
computes; the document's circular form differed for low > high.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
FILL ERASE MOVE, COUNT CMOVE CMOVE> BLANK -TRAILING COMPARE SEARCH SCAN
SKIP, as loops over the call-free C@ and C!, executed on the golden
model at both cell widths against C and five recorded transcripts of
the v3 binary.
A negative count reads as 0 where v3 read it so, and elsewhere writes
nothing and sets NODE-ERROR. v3's counted-string auto-detection is not
kept in any of them.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
One case per byte position, like C!: the cell is shifted down with a
2/ loop and masked. It replaces the version built on LSHIFT, RSHIFT
and SWAP calls. C@ now leaves its caller 7 return entries (was 4), and
the words above it gain with it: TYPE 6 (was 3), DUMP 4, Q.PRINT, U.
and U.R 3 (were 2). The signed number words stay at 2: their sign
waits on the return stack.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
BASE and HLD leave their variable's word address; DECIMAL, HEX and
OCTAL store 10, 16 and 8. Executed on the golden model at both cell
widths, including a recorded transcript of the v3 binary.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Built on the number-output words and executed on the golden model at
both cell widths against a C reference and recorded transcripts of the
v3 binary (DUMP byte for byte at 64-bit cells).
Q.PRINT is signed (D-8) and always decimal; DUMP is always hex; both
put BASE back. Each keeps its working state in a variable, (QP) and
(DP), so each leaves its caller 4 data cells and 2 return entries.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The number-printing words, on pictured output and TYPE, executed on the
golden model at both cell widths against a C reference (ten bases,
eleven field widths) and six recorded transcripts of the v3 binary.
Each plain word is its .R word with a width of 0; all six share one
tail. The field width waits in a variable, (W), so the picture runs no
deeper than it does on its own: each word leaves its caller 4 data
cells and 2 return entries.
As v3, the .R words print a trailing space. Unlike v3, D. takes
( lo hi ), prints the whole double, and printing honours BASE.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
: EMIT ( c -- ) CONSOLE-TX b! !b ;
: CR ( -- ) 10 jump EMIT
: SPACE ( -- ) 32 jump EMIT
: TYPE ( baddr u -- )
-if OK drop drop NODE-ERROR b! -1 !b ;
OK: if DONE over C@ EMIT push 1 + pop -1 + jump OK
DONE: drop drop ;
They follow v3 (v3/src/word_source/io_words.c): EMIT prints the low byte
of the cell, CR character 10, SPACE a blank; TYPE prints u bytes,
nothing for u = 0, and for u < 0 nothing, with NODE-ERROR set where v3
raised its error flag. TYPE does not check the address range, which v3
does; out-of-range addressing is still an open question in node.h.
New test v4/tests/test_terminal.c, on a node of its own with the console
attached, 939 checks per width. Two transcripts of the real v3 binary
are recorded as expected output:
65 EMIT 66 EMIT SPACE 67 EMIT CR 68 EMIT 321 EMIT -> "AB C\nDA"
S" Hello, v3" TYPE 91 EMIT <text> 0 TYPE 93 EMIT -> "Hello, v3[]"
Also: EMIT of every byte and of wider values, CR, SPACE, TYPE from every
start within a cell at lengths 0..40, bytes with the top bit set and
zero bytes, negative counts, and that TYPE writes no memory. At 32- and
64-bit cells, optimised and ASan+UBSan (`make test`, `make sanitize`).
Five mutations each fail.
Headroom (data cells under args / return entries): EMIT 8/8, TYPE 4/3.
TYPE's depth is C@'s, which is still as written (C@ -> RSHIFT -> SWAP).
Test results on the amd64 host only. This is a development check, not
acceptance (JUSTIFICATION.md section 16).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
EMIT is a device service: a character sent to the console node. The
mesh and its ports are development step 2 and the memory map is open
(D-4), so the single-node model now stands in for the console with one
memory-mapped register, so that printing words can be run and their
output compared with v3's.
v4_node_console_attach(n, addr): after it, a store to word address
`addr` appends the low 8 bits of the value to a buffer on the node
(V4_CONSOLE_CAP characters, 4096 by default) and does not write memory;
a load from `addr` reads the memory word as before. Characters past the
capacity are counted in console_dropped and discarded. The hook is in
v4_node_store, which all four store opcodes use.
It is off by default: v4_node_reset detaches the console (address -1)
and empties the capture, so the ISA's behaviour and every existing test
are unchanged unless a console is attached. The address is the
caller's choice.
New test v4/tests/test_console.c, 22 checks per width: direct stores,
!b, ! and !+ through the executor printing "Hi!", memory at and around
the register untouched, the low byte only, overflow, detach, a console
at word 0, and reset. At 32- and 64-bit cells, optimised and ASan+UBSan
(`make test`, `make sanitize`); all other v4 tests still pass. Four
mutations of the hook each fail.
DECOMPOSITION.md section 7 gains the CONSOLE-TX row. No printing word is
defined here; EMIT and the words on it are still to do.
Test results on the amd64 host only. This is a development check, not
acceptance (JUSTIFICATION.md section 16).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
`#` held the high quotient on the return stack across its second
UM/MOD, which was the deepest point of pictured output once C! was made
call-free. It now rotates it under the division on the data stack
(-ROT in line: SWAP push SWAP pop).
Headroom, return entries: <# #S #> 2 -> 3, the signed picture 1 -> 2.
Data room is unchanged.
Same 4716 checks per width at 32- and 64-bit cells, optimised and
ASan+UBSan (`make test`, `make sanitize`); the headroom checks now
require the new figures.
Test results on the amd64 host only. This is a development check, not
acceptance (JUSTIFICATION.md section 16).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
C! as written in 5.3 called RSHIFT and LSHIFT (which call SWAP) and OR.
It is now one straight-line case per byte position: the byte is shifted
up with a `2* unext` loop, that byte of the cell cleared with a constant
mask, and the two added. The word address is `2/ 2/` of the byte
address. The upper half of a 64-bit cell is still preserved.
Headroom (data cells under args / return entries): 5/4 -> 7/7.
Same checks as before (every byte of two adjacent words, eight values,
neighbours and the upper half untouched) at 32- and 64-bit cells,
optimised and ASan+UBSan (`make test`, `make sanitize`). Four mutations
fail, one of them only at 64-bit cells, where it differs.
test_pictured.c carries the same C!. The pictured words did not gain
return-stack room from this: <# #S #> still leaves 2 entries and the
signed picture 1. With C! shallow, the deepest point is now inside `#`,
which holds the high quotient on the return stack across its second
UM/MOD. Recorded in 5.8; `#` is unchanged.
Test results on the amd64 host only. This is a development check, not
acceptance (JUSTIFICATION.md section 16).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
DECOMPOSITION.md 5.8 only named these as "standard pictured-output
definitions over UM/MOD and a hold buffer". They are now written out
(5.8) and run on the golden model.
D-13 (ruled 2026-10-03): the hold buffer takes 63 characters, as v3's;
HOLD of a value outside 0-255, or into a full buffer, stores nothing and
sets NODE-ERROR, which is what v3 did with its error flag.
Behaviour follows v3 otherwise: digits 0-9 then A-Z, BASE outside 2..36
reads as 10, SIGN ( n -- ). Stack effects are the standard ones, as 5.8
already ruled (v3 took its double low cell on top). The buffer is 64
bytes, filled backwards from its end through HLD; `#` divides by the
base in two UM/MOD steps. HOLD, SIGN and # end in a jump to the next
word instead of a call, which saves two return-stack entries: with
calls, the signed picture `.` needs overflowed the 9-deep return stack.
New test file v4/tests/test_pictured.c, on a node of its own:
test_foundation.c's hand-assembled words already fill 901 of a node's
1024 words. It re-assembles SWAP, OR, UM/MOD, LSHIFT, RSHIFT and C! as
they are in test_foundation.c.
Checked against a C reference (short division on 16-bit limbs) at 32-
and 64-bit cells, optimised and ASan+UBSan (`make test`, `make
sanitize`), 4716 checks per width: <# #S #>, <# # # 46 HOLD #S #> and
the signed picture, in bases 10, 16, 2, 8, 36, 3 and the invalid 0, 1,
37, -5, on every pair of 15 edge cells; HOLD of 12 values; and a base-2
number that overflows the buffer (63 characters kept, NODE-ERROR set,
nothing outside the buffer written). Six mutations all fail.
Headroom: <# #S #> leaves 3 data cells and 2 return entries; the signed
picture leaves 1 return entry. The depth is C!'s as written (C! ->
LSHIFT -> SWAP), which is unchanged.
Test results on the amd64 host only. This is a development check, not
acceptance (JUSTIFICATION.md section 16).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Both run exactly as written in DECOMPOSITION.md 5.3 and need no change:
four bytes to a cell, little-endian, byte address = 4 * word address +
byte index, at either cell width.
Checked at 32- and 64-bit cells, optimised and ASan+UBSan (`make test`,
`make sanitize`): every byte of two adjacent words, eight values
including ones wider than a byte, with the other bytes of the word, the
upper half of a 64-bit cell and the neighbouring words left untouched.
Breaking C!'s mask or C@'s mask fails.
Headroom (data under args / return): C@ 6/4, C! 5/4.
Test results on the amd64 host only. This is a development check, not
acceptance (JUSTIFICATION.md section 16).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Both run exactly as written in DECOMPOSITION.md 5.5 and need no change.
Checked against C on the edge vectors for every count 0 .. N (a count
of N gives 0), at 32- and 64-bit cells, optimised and ASan+UBSan
(`make test`, `make sanitize`). Removing RSHIFT's sign-bit mask fails.
Headroom (data under args / return): 7/5 each.
They are dependencies of C@ and C!, which the pictured-output hold
buffer needs.
Test results on the amd64 host only. This is a development check, not
acceptance (JUSTIFICATION.md section 16).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
