The turn's RNG cost has never been measured end to end. combat-done-tail.md
found two draw sites in OnAllCombatDone_Tail that nothing models and that both
run before the autosave, so a reimplementation that reproduces both ProcessTurn
functions exactly still diverges the first turn a node line expires.
RngLedger recovers an ABSOLUTE WORD POSITION from (mt[624], left) alone, by
indexing the forward-only chain of blocks the twist generates. Word deltas
between any two observations are then exact -- across twists, across NextInt
rejection loops, and across draws nobody hooked. That last point is not
theoretical: the image has four draw entry points, one of which (NextUInt
0x004f7670) appears in no previous lane's primitive set, plus inlined draws in
twelve functions. A primitive-counting hook would have undercounted silently.
Six nested trace hooks bracket one End Turn between the two autosaves and
attribute the words: the two turn drivers, the two tail phases that can draw,
and ProcessNodeSpaceTravel because it runs twice a turn. NodeLineDecay carries
a real model -- one word per expired node line under NodePath::RemainingLife --
so compare mode checks the count rather than reporting it.
Corrections from the instruction stream, both load-bearing:
* StrategyHost::Autosave is ret 8, not ret 4, and returns the std::string* in
EAX. A void-returning hook would have dropped it at both call sites.
* node-line decay's 0x20000-fleet skip runs AFTER the Chance(0.5f) call, not
before, so it cannot change the draw count -- combat-done-tail.md reads as
if it gated the roll.
fpu.sample_turn releases StrategyServer::ProcessTurn, which the fpu sampler and
this ledger both want and MinHook grants to one of them. Default on: no
existing run changes behaviour.
Host ctest 37/37; shim cross-built on CT111; clean-room check OK.
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