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>
First code for StarForth v4 (JUSTIFICATION.md section 10, step 1): one node
of the 32-instruction core as a C99 model, with cell width as a build
parameter.
- Node: P, A, B, F18 circular stacks (10 and 9 deep, D-2), word-addressed
memory (D-1), 5% guard bands on every bounded list.
- Instruction word: six 5-bit slots in 32 bits at every cell width.
- Executor: all 32 opcodes of DECOMPOSITION.md 1.3. Cell arithmetic wraps
explicitly; no signed overflow or implementation-defined shift.
- Heat: per-opcode and per-call-target counters and the anti-clock, driven
by instruction retirement (1.4, D-6 interim).
- Slot packer and runner for tests, and a reference unsigned multiply in
plain C99 with no 128-bit type.
Tests run at 32- and 64-bit cells, and under ASan and UBSan. They cover
every opcode and execute the first section 4 definitions (NIP SWAP OR
NEGATE ROT 0< 0= 2DUP - U<) against the C operation each stands for.
UM* as written in section 4 is exact only while u1 <= 2^(n-2). Two known
failing cases are pinned in test_foundation.c until it is rewritten.
DECOMPOSITION.md: record D-9, the instruction word is 32 bits at every
cell width (ruled 2026-10-02).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
