rajamesandClaude Opus 5.5
981f4180ce
DECOMPOSITION.md 5.26 described both words in prose only. They are now
written out, call-free, on one observation: +* with S = 0 never adds, so
each step is an exact arithmetic right shift of the double T:A.
: Q.FROM-INT ( n -- q ) push 0 a! 0 pop 15 FOR +* UNEXT push drop a pop ;
T:A = n:0 is n * 2^N; N-16 shifts leave n * 2^16 (count 15 at
32-bit cells, 47 at 64).
: Q.TO-INT ( q -- n ) push a! 0 pop 15 FOR +* UNEXT drop drop a ;
16 shifts at every width; the low cell is left in A. Rounds toward
minus infinity, as v3's arithmetic shift does.
Both clobber A; added to the section 2 list.
Checked at 32- and 64-bit cells, optimised and ASan+UBSan:
- Q.FROM-INT against n * 2^16 for edge values and 20000 pseudo-random n,
and against v3's q48_from_u64 for n >= 0 (low cell at 64-bit, D-10).
- Q.TO-INT against v3's (int64_t)q >> 16 on the edge Q values and 20000
pseudo-random Q values, and against a C double shift on 20000
arbitrary doubles.
- Round trip Q.TO-INT(Q.FROM-INT(n)) = n.
Mutating either shift count or the S = 0 setup fails 40000+ checks.
Note: make sanitize prints UBSan reports but does not fail on them. One
was found here, in the test's own random shift amount (fixed); a grep of
the full sanitize output now shows no runtime errors.
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.
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.