rajamesandClaude Opus 5.5
2930349bbf
The boot is now nucleus, forth79.4th, POST, prompt, on both products. - forth79.4th: U* and U/MOD, the capsule's first colon definitions. They are in the FORTH-79 Required Word Set and neither v3 nor v4 had them. - post79.4th: 550 cases, 126 of the 130 required words. 443 are v3's with v3's result. The rest follow three rulings (2026-10-05): address- dependent cases are checked for count, not value; where v3 departs from FORTH-79 the standard's result is expected; words v3 has no case for get cases written by hand. v4/tools/post79_rules.py holds each exception with its reason and docs/v4.0.0/POST79.md lists them all. - every case starts from an empty stack, DECIMAL and FORTH DEFINITIONS - the boot requires POST's tally line with fail=0 Verified: tests=550 pass=550 fail=0 and identical PARITY lines on hosted amd64, aarch64 and riscv64 (make -C v4 hosted-check) and on bare metal, clean qemu with STARFORTH_V4=1, on the same three (logs/20261005-1619xx, -1621xx, -1625xx). A U/MOD broken on purpose fails five cases and stops the boot. make -C v4 test passes. Not shown: all words but those two are still assembled, so POST has so far tested the assembled words. Nothing was typed at a bare-metal prompt. Open: PAD 42 OVER ! faults on v4 (D-1). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
v4/
StarForth v4: the 32-instruction F18-derived core. The design lives in
docs/v4.0.0/JUSTIFICATION.md (why) and docs/v4.0.0/DECOMPOSITION.md
(every v3 word mapped to a v4 fate).
The first deliverable is the hosted C99 golden model (JUSTIFICATION.md §10,
step 1). It must pass POST and hold K≡1.0 with 32- and 64-bit cells on all
three host ISAs.
Acceptance (JUSTIFICATION.md §16): v4 must be equivalent to v3 at any point
in time, with the same vocabularies and behaviour, on the F18-derived engine;
and every ISA, hosted and bare metal, must still reach its ok prompt.
make -C v4 test passing is a development check, not acceptance.
What exists so far is the single node: registers, circular stacks, memory, all
32 opcodes, per-opcode and per-call-target heat, and three console
registers (CONSOLE-TX, which captures output, and CONSOLE-RX and CONSOLE-STATUS, which hand out
input a test feeds) standing in for the console node until the mesh exists. The tests load definitions
onto a node either opcode by opcode (v4/include/v4/asm.h) or as text in the notation DECOMPOSITION.md
uses (v4/include/v4/text.h). make -C v4 test builds
and runs the tests at both cell widths; make -C v4 sanitize repeats them
under ASan and UBSan. There is no POST and no K measurement yet.
The system: nucleus, capsules, prompt
docs/v4.0.0/NUCLEUS.md is the design. A v4 system is four things:
| Part | Where | What it is |
|---|---|---|
| Engine | v4/src |
The golden model of the 32-opcode node |
| Nucleus | v4/capsule/*.v4, built by v4/tools/mkimage.c |
The assembled words, as a memory image linked into the binary |
| Capsules | capsules/v4/*.4th, baked by tools/mkcapsule.c |
FORTH source, loaded when the system comes up |
| Boot | v4/system/boot.c |
Starts the nucleus, checks and loads each capsule, prints the parity lines, gives the prompt |
Two products link the same four and differ only in the console:
- Hosted Linux,
v4/tools/hosted.c:make -C v4 hostedbuildsv4/build/starforth4-amd64,-aarch64and-riscv64, static, 64-bit cells. - Bare metal,
kernel/src/v4/sk_v4.c:make -f kernel/Makefile ARCH=<arch> STARFORTH_V4=1.
A boot prints:
PARITY:V4_NUCLEUS words=292 image_hash=0x...
PARITY:V4_CAPSULE name=v4:forth79.4th capsule_id=0x... capsule_hash=0x... dict_hash=0x...
PARITY:OK
ok>
Every build of one commit prints the same hashes. make -C v4 hosted-check
boots the three hosted binaries (the two foreign ones under user-mode QEMU)
and fails unless their output is identical and ends in PARITY:OK.
A capsule line the node does not answer ok to ends the boot, naming the
capsule, block and line, with PARITY:FAIL and POST: FAILED.
State, 2026-10-05: all six builds start the nucleus, load v4:forth79.4th,
pass POST and reach ok>, with the same lines:
PARITY:V4_NUCLEUS words=295 image_hash=0x3ed5d5fc83f0b026
PARITY:V4_CAPSULE name=v4:forth79.4th capsule_id=0x4055641ee17d176b capsule_hash=0x4055641ee17d176b dict_hash=0x1ec33b48cc76a0b5
PARITY:V4_POST tests=550 pass=550 fail=0
PARITY:V4_CAPSULE name=v4:post79.4th capsule_id=0xb987dbb4388990bd capsule_hash=0xb987dbb4388990bd dict_hash=0x671fdd7aebf0f8d8
PARITY:OK
POST: PASSED
ok>
Bare-metal logs: logs/20261005-161924/amd64/, logs/20261005-162142/aarch64/,
logs/20261005-162524/riscv64/. Each run was ended once the prompt was in the
log; nothing was typed at a bare-metal prompt, so keyboard input there is not
yet verified. The capsules were unsigned (no signing key on this machine).
What this does not yet show. forth79.4th holds two definitions, U*
and U/MOD. Every other word is still in the assembled nucleus, so POST is
so far a test of the assembled words. Moving them to the capsule, a group at
a time with POST after each, is the next step (NUCLEUS.md section 8).
POST
capsules/v4/post79.4th: 550 cases in blocks 7000 up, covering 126 of the
130 words of the FORTH-79 Required Word Set. 443 are v3's cases with what
the hosted v3 binary did as the expected result. The other 107, and the 27
v3 cases left out, are listed with reasons in docs/v4.0.0/POST79.md.
make -C v4 postboots the amd64 system: the quick check after a change.make -C v4 hosted-checkboots all three hosted ISAs and compares them.make -C v4 post79writes the capsule again (tools/mkpost.py,tools/post79_rules.py); it needs the hosted v3 binary.
POST is FORTH: a harness of FORTH-79 words and two nucleus hooks, (CATCH)
and (EMIT-HOOK). It forgets itself when it has finished. The boot passes
only on seeing POST's tally line with fail=0 (v4/system/boot.c). A colon
definition broken on purpose (U/MOD without its last SWAP) fails five
cases and the boot stops with POST: FAILED.
Not tested: KEY, EXPECT, QUERY (the keyboard) and QUIT (it returns
without ok).
Open: PAD 42 OVER ! faults on v4, because PAD is a byte address and !
takes a cell address (D-1). FORTH-79 expects it to work. The v3 case for it
is left out until that is ruled.
The Required Word Set list in tools/mkpost.py was written from memory of
the standard and has not been checked against the document.