Hojun-Cho
e8977a413d
A tagged leaf at the end of a dot chain (depth >= 2) fell to the
one-word scalar tail in FOUR walkers — the value-chain read spine,
the value-chain assign walker, the chained-*struct read branch, and
the chained-*struct assign branch — in BOTH stages, byte-identical,
gate-blind:
READ: one MOVQ pulled the TAG word only; is-tests passed by
tag-luck while as/match/let consumers read stale DX/CX/R8
as payload (ken x5c: o.r.min as size added entry-zero DX —
want 28 got 20; ken b8 same through a mid-chain *rep).
ASSIGN: one sized store landed the rhs ON the tag slot, payload
kept its old bytes (ken x5d: `o.r.min = 8: size` made the
following is-test false).
The single-dot arms were already correct — each fix is that arm
verbatim at the chained site:
read: the tagged cursor (AX=tag, DX=val0, R8=val2 before
CX=val1 — the base may live in CX/AX; >32B box leaves its
ADDRESS in AX, the #37 mem-read convention). wwstage rides
the existing cgloadtaggedfield helper; the *struct-base
branches stage AX into BX first (cursor targets AX).
assign: full slot rewrite via the shared widener
(cg_widen_tagged_store / cgwidentaggedstore, base BX/BP),
plain `=` only — compound on tagged stays loud (#133).
The nested-LITERAL half of the old #38 filing dissolved: the
canonical fill's tagged-field widen delegation (#23, 413aafa) already
covers any depth — x5c's literal init emits a correct tag at HEAD;
only the chained READ/ASSIGN halves were live (probe-proven, asm at
/tmp/pB).
Probes converge byte-id and runtime-correct: x5c/d/e (28), depth-2
(b3/b9), (void|str) 32B box + match readback (b5), *outer root (b7),
mid-chain *rep (b8), non-tagged control (f38a). 938 rows chained_*
pin all six shapes. Residuals filed, not folded (rule 11): the
INDEX-spine sibling xs[i].min payload read (task #58); tagged-field
GLOBALS stay loud at DATA emit (#129 A.2), so the walkers'
global arms are mirror-only today.
Task #38.