849c5069fc
Seven End Turns from ref-turn2.sav on VM140, six control words, whole-state checksum on every post-turn autosave. 53-bit and 64-bit x87 give byte-identical state across all 35,394 leaves, so an x64/SSE port computing in IEEE double has NO double-rounding budget to preserve and floats=bits is free. Two settings do move state, each reproduced on a repeat run: 0x007f (24-bit) Sys[112 "Gamma Cephei"]/Pop2/PopG/PopC 540000000 -> 540000002 0x1a7f (round-up) Flt[34 "Beta Fleet"]/Pos/.[0] and /Pos/.[2], 1 ULP each So the port must hold intermediates at 53 bits and use round-to-nearest -- both SSE defaults, now measured rather than assumed, each with a named regression witness. The briefed triple was under-powered: 0x027f is 53-bit (it differs from 0x127f only in bit 12, infinity control, ignored since the 387) and 0x137f is 64-bit, not a rounding change. Run as written all three come back identical, and that would have "proved" something false on both axes that matter. Evidence the forced word actually held: read-back at each force site plus 38 independent in-pipeline hook samples per run spanning turn phases 4, 6 and 8, all reading the forced value. Mars::Application::Run calls _controlfp(0x50000,0x3070300) at 0x0089f606 every frame, which is 0x127f, so forcing at StrategyClient::EndTurn is wiped before the turn runs; StrategyServer::BeginProcessTurn is the point that works. Also re-confirms the End-Turn determinism oracle on engine cef889e: bb4fd9ac... / 978041ac... unchanged. New tools: verify/fpu-cw/cw_census.py, verify/fpu-cw/trace_bitdiff.py (the latter exists because under a forced 24-bit word the CRT's own %g rendering degrades, so trace text is not a valid comparison surface).
50 lines
2.9 KiB
Text
50 lines
2.9 KiB
Text
===== 127f vs off =====
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A verify/results/fpu-cw/run-127f/shim.trace.jsonl.gz
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B verify/results/fpu-cw/run-off/shim.trace.jsonl.gz
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Game::ServerSystem::ProcessTurn: 6 leaf difference(s) over 28 record(s)
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rec[4] .coverage.n: 3 -> 1
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rec[4] .coverage.undeclared: [{'region': 'system', 'off': 420, 'len': 3}, {'region': 'system', 'off': 424, 'len': 3}, {'region': 'system', 'off': 428, 'len': 3}] -> [{'region': 'system', 'off': 420, 'len': 12}]
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rec[15] .coverage.n: 6 -> 4
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rec[15] .coverage.undeclared: [{'region': 'system', 'off': 216, 'len': 1}, {'region': 'system', 'off': 368, 'len': 1}, {'region': 'system', 'off': 420, 'len': 3}, {'region': 'system', 'off': 424, 'len': 3}, {'region': 'system', 'off': 428, 'len': 3}, {'region': 'system', 'off': 568, 'len': 4}] -> [{'region': 'system', 'off': 216, 'len': 1}, {'region': 'system', 'off': 368, 'len': 1}, {'region': 'system', 'off': 420, 'len': 12}, {'region': 'system', 'off': 568, 'len': 4}]
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rec[16] .coverage.n: 3 -> 1
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rec[16] .coverage.undeclared: [{'region': 'system', 'off': 420, 'len': 3}, {'region': 'system', 'off': 424, 'len': 3}, {'region': 'system', 'off': 428, 'len': 3}] -> [{'region': 'system', 'off': 420, 'len': 12}]
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Game::StrategyServer::MoveFleet: 0 leaf difference(s) over 7 record(s)
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Game::TechTree::ProcessResearch: 0 leaf difference(s) over 3 record(s)
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TOTAL: 6
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===== 127f vs 007f =====
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A verify/results/fpu-cw/run-127f/shim.trace.jsonl.gz
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B verify/results/fpu-cw/run-007f/shim.trace.jsonl.gz
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Game::ServerSystem::ProcessTurn: 0 leaf difference(s) over 28 record(s)
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Game::StrategyServer::MoveFleet: 0 leaf difference(s) over 7 record(s)
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Game::TechTree::ProcessResearch: 0 leaf difference(s) over 3 record(s)
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TOTAL: 0
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===== 127f vs 027f =====
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A verify/results/fpu-cw/run-127f/shim.trace.jsonl.gz
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B verify/results/fpu-cw/run-027f/shim.trace.jsonl.gz
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Game::ServerSystem::ProcessTurn: 2 leaf difference(s) over 28 record(s)
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rec[15] .coverage.undeclared[2].len: 3 -> 2
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rec[15] .coverage.undeclared[2].off: 420 -> 421
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Game::StrategyServer::MoveFleet: 0 leaf difference(s) over 7 record(s)
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Game::TechTree::ProcessResearch: 0 leaf difference(s) over 3 record(s)
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TOTAL: 2
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===== 127f vs 137f =====
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A verify/results/fpu-cw/run-127f/shim.trace.jsonl.gz
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B verify/results/fpu-cw/run-137f/shim.trace.jsonl.gz
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Game::ServerSystem::ProcessTurn: 0 leaf difference(s) over 28 record(s)
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Game::StrategyServer::MoveFleet: 0 leaf difference(s) over 7 record(s)
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Game::TechTree::ProcessResearch: 0 leaf difference(s) over 3 record(s)
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TOTAL: 0
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===== 127f vs 1a7f =====
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A verify/results/fpu-cw/run-127f/shim.trace.jsonl.gz
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B verify/results/fpu-cw/run-1a7f/shim.trace.jsonl.gz
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Game::ServerSystem::ProcessTurn: 0 leaf difference(s) over 28 record(s)
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Game::StrategyServer::MoveFleet: 2 leaf difference(s) over 7 record(s)
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rec[6] .side.pos.after.v.x.bits: 3240690712 -> 3240690711
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rec[6] .side.pos.after.v.z.bits: 1070090545 -> 1070090546
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Game::TechTree::ProcessResearch: 0 leaf difference(s) over 3 record(s)
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TOTAL: 2
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