rajamesandClaude Opus 5.5
e117333a87
Q.LOG is v3's q48_log_approx: x = 2^k * m with 1.0 <= m < 2.0, ln m by up to 6 Newton rounds on e^y = m, result y + k * ln 2. As ruled, e^y is Q.EXP's Taylor loop written in line rather than a call to Q.EXP, so Q.LOG calls only Q.*, Q./ and UM*. After the reduction m, y, the Taylor term and its sum each fit one cell, so the 7-cell variable (QL) holds single cells. x <= 0 returns 0 and sets NODE-ERROR (D-12). Checked bit for bit against v3's q48_log_approx (ported into the test) on 22 positive edge values, 2000 pseudo-random x of every magnitude and a sweep of every 17th reduced m, at 32- and 64-bit cells, optimised and ASan+UBSan (`make test`, `make sanitize`). Mutating the round count, the 100-ulp stop, ln 2 or the Taylor length all fail. v3's clamp y = max(y - corr, 0) is kept but cannot fire: a scan of all 65536 values of m in C never reaches it, and never needs more than 4 rounds. So no test covers it. The test harness's per-call step limit is raised from 100000 to 4000000 instruction words: a 64-bit Q./ takes about 6500, and a mutant forcing extra Newton rounds ran past the old limit and looked like a width difference. Headroom (data under arg / return): Q.LOG 3/2. 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>
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, and per-opcode and per-call-target heat. 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 compiler capsule, no POST and no K
measurement yet.