Cesarus85--mjolnir-vr/research/circular_queue_obj/EXPERIMENTS.md

circular_queue.obj strict closeout ledger

Baseline

• Canonical base: e54ead79c.
• Compiler: XDK 3911 CL 13.00.9254.1, /O2 /Oy- /DDEBUG /Dxbox.
• Seven functions are strict-exact.
• _circular_queue_dequeue_data: target 0x100, candidate 0xF0, 12 relocations each.
• Historical commits 73ce982b0/634fd66a7, c5514492d, and d63b25044/53e1dab90 are treated as the prior evidence ledger.
• The locally available VC7 13.00.9210 compiler was also tested against the unchanged source. It emits the same 0xF0 candidate and normalized SHA 40adf3be... as 13.00.9254.1; the residual is not resolved by the only alternate authentic compiler binary available locally.
• The October 2001 beta XBE contains the same dequeue implementation instruction-for-instruction (function VA 0x00118fb0), including xor bl,bl, the later EBX=read_offset coalescing, and dual success/failure epilogues. This proves the topology was stable across builds but exposes no source/local-variable records.

Excluded historical repetitions

The prior lanes already tested five legal-C lifetime/control-flow families around the result, read_offset, and final advance write. They preserved the semantic relocation identities but did not make VC7 keep FALSE in BL or coalesce EBX with read_offset. These families will not be rerun without new provenance or a demonstrably different control.

New experiments

ID	Evidence-backed source control	Size/relocs	First divergence	Outcome
N1	Claude's previously designed but never executed early-failure return: initialize result=FALSE, return it when data_size > size, and return literal TRUE after the copy.	0xF0, 12	+0x4, queue remains in EBX; fail epilogue emitted at +0x5b with xor al,al.	Rejected. It duplicates an epilogue but does not keep the false value live in BL, and makes relocation-address drift worse.
N2	Keep January's success-first block layout, but return literal TRUE inside it and return initialized result only from the trailing failure path.	0xF0, 12	+0x4; normalized SHA unchanged from canonical (40adf3be...).	Rejected/no effect. VC7 still folds the failure value to xor al,al; this is source-equivalent to canonical at optimized IR.
N3	Make the initialized result participate in the success guard: if (!result && data_size <= circular_queue_size(queue)). This tests a zero-byte SSA/lifetime anchor while preserving semantics.	0xF0, 12	+0x4; normalized SHA unchanged (40adf3be...).	Rejected/no effect. The redundant predicate is eliminated before register allocation.
N4	Explicitly model January/October's disjoint register lifetime with a scalar union overlaying boolean result and long read_offset; return TRUE on success and the union's boolean on failure.	0xF0, 12	+0x4; normalized SHA unchanged (40adf3be...).	Rejected/no effect. VC7 scalarizes the union and still constant-folds the failure value.
N5	Put boolean result = FALSE first in the declaration list (the historical/source-natural priority), use a literal success return inside the block, and reserve result for the trailing fail return.	0xF0, 12	+0x4; normalized SHA unchanged (40adf3be...).	Rejected/no effect. Declaration initialization/order does not alter the allocator in this combination.
N6	Insert a zero-byte _ReadWriteBarrier() immediately after result=FALSE, retaining canonical control flow.	0xF0, 12	+0x6; SHA f803ad9d....	Partial structural movement only: prologue push order now matches January, but queue still claims EBX, no xor bl,bl is emitted, and failure remains xor al,al.
N7	Combine N6 with the historical outer if (result && advance) writeback/return topology.	0xF0, 12	+0x6; SHA 9ae0aa56....	Rejected. Barrier aligns prologue scheduling, but the result still folds and the old shared-tail shape remains.
N8	Preserve the result as a late PHI by switching on it after the copy block, with distinct success/default returns.	0x100, 12	+0x3; SHA ac2dc1a8....	Exact padded size, but not a near match: VC7 spills result to [ebp-1], creates a frame and emits switch-dispatch instructions.
N9	Replace N8's switch with if (result == TRUE) and distinct returns.	0xF0, 12	+0x4; SHA 40adf3be....	Rejected/no effect. The simpler late branch is folded completely.
N10	Switch directly on the runtime availability predicate so the failure result dies before read_offset begins.	0x100, 12	+0x4; SHA 107cae55....	Exact padded size only; VC7 emits setle plus switch-dispatch overhead and an inline failure epilogue, not January's direct jg/tail failure.
N11	Combine N6's partial prologue alignment with N9's explicit outer success branch.	0xF0, 12	+0x6; SHA f803ad9d....	Rejected/no effect beyond N6.
N12	Use two zero-byte barriers (after FALSE initialization and after the success assignment), following the scenario two-barrier precedent.	0xF0, 12	Prologue remains queue-in-EBX; SHA 1f080135....	Rejected. It changes optimized control flow but still does not materialize FALSE in BL or reach target size.
N13	Scope read_offset and contiguous_size inside the success block while retaining canonical result flow.	0xF0, 12	+0x4; SHA 40adf3be....	Rejected/no effect. VC7 recovers the canonical lifetimes.
N14	N13 plus register boolean result.	0xF0, 12	+0x4; SHA 40adf3be....	Rejected/no effect. /O2 ignores the hint for this allocation decision.
N15	N14 plus a local queue_reference alias used by the complete function.	0xF0, 12	+0x4; SHA 40adf3be....	Rejected/no effect. The alias is eliminated.
N16	Use result++ instead of result=TRUE on the success edge.	0xF0, 12	+0x4; SHA 40adf3be....	Rejected/no effect. Boolean range propagation folds it to the canonical form.
N17	Store the result in a one-byte local structure.	0xF0, 12	+0x4; SHA 40adf3be....	Rejected/no effect. The aggregate is scalarized.
N18	Single-iteration do loop with a failure break, then the copy body and result=TRUE.	0x150, 17	+0x5; SHA 8e348c3a...; 267 differing bytes.	Important partial. It creates January's xor bl,bl, dual tails, and later EBX=read_offset, but causes circular_queue_verify to inline again inside the already-inlined size path, adding 80 padded bytes and five relocations.
N19	N18 plus __declspec(noinline) on circular_queue_verify.	0xF0, 12	+0x4; SHA 40adf3be....	Rejected. Preventing the nested inline also destroys the desired BL lifetime and returns to baseline.
N20	N18 with the size expression written manually from queue fields and one validator call.	0x150, 17	+0x5; SHA 8e348c3a....	Rejected. The direct validator is still inlined and produces the same oversized object.
N21	N20 with a local function pointer used for the validator call.	0x100, 12	+0x4; SHA 9339ad1b...; 68 differing bytes.	Closest local dequeue shape, but rejected: address-taking changes the validator from its target private EAX convention to cdecl and regresses the validator/caller sibling cluster.
N22	N20 plus __declspec(noinline) on the validator.	0xF0, 12	+0x4; SHA 40adf3be....	Rejected; same fixed point as N19.
N23	Single-iteration loop expressed as do ... while (result == FALSE).	0x150, 17	+0x5; SHA 8e348c3a....	Rejected; same nested-inline fixed point as N18.
N24	N23 plus __declspec(noinline) validator.	0xF0, 12	+0x4; SHA 40adf3be....	Rejected; same baseline fixed point as N19.
N25	N23 plus _ReadWriteBarrier() at validator entry.	0x150, 17	+0x5; SHA 8e348c3a....	Rejected. The barrier preserves the standalone validator but does not stop the optimizer from cloning/inlining its body at the nested call.
N26	N23 plus noinline validator and _ReadWriteBarrier() after FALSE initialization.	0xF0, 12	+0x7; SHA f803ad9d...; 218 differing bytes.	Rejected; reproduces N6's partial prologue movement without BL materialization.
N27	while (TRUE) with explicit failure and success break statements.	0xF0, 12	+0x4; SHA 40adf3be....	Rejected/no effect. The loop simplifies to canonical IR.
N28	Explicit goto dequeue_done on failure with a success-only copy block.	0xF0, 12	+0x4; SHA 40adf3be....	Rejected/no effect. VC7 folds it to canonical IR.
N29	__forceinline helper returning FALSE for result initialization.	0xF0, 12	+0x4; SHA 40adf3be....	Rejected/no effect. The helper and value fold away.
N30	__forceinline helper returning data_size <= circular_queue_size(queue).	0xF0, 12	+0x4; SHA 40adf3be....	Rejected/no effect. The helper folds into the canonical comparison.
N31	Historical declaration initializer plus inner advance and result assignment after advance.	0xF0, 12	+0x4; SHA 40adf3be....	Rejected/no effect.
N32	Reverse the comparison spelling to circular_queue_size(queue) >= data_size.	0xF0, 12	+0x4; SHA bbe01e24....	Rejected. It changes comparison orientation (cmp eax,esi/jl) but preserves the wrong allocation and moves away from January.
N33	Assign result before the optional advance write.	0xF0, 12	Early success-tail divergence; SHA c3d7f616....	Rejected. It creates the historical shared success epilogue rather than January's literal-success/failure-BL tails.
N34	Force-inline wrapper around validator combined with the N18 loop.	0x150, 17	+0x5; SHA 8e348c3a....	Rejected; recursive/nested inlining remains.
N35	Ordinary static wrapper around validator combined with the N18 loop.	0x150, 17	+0x5; SHA 8e348c3a....	Rejected; wrapper also inlines to the same oversized fixed point.
N36	Move the private validator definition immediately after reset, matching January's observed function-symbol order; canonical dequeue body.	0xF0, 12	+0x4; full SHA 40adf3be1fa79c0b9aaf6b169e37da2e59aa4e306efef68a9573b7aa7ec8dede; 222 differing bytes.	Rejected/no effect. Function-definition order does not change the canonical allocator/inliner fixed point. All seven siblings remain exact.
N37	N36 definition order combined with N18's single-iteration failure-break loop.	0x150, 17	+0x5; full SHA 8e348c3ab923622446e3d5b4ff940cfd3e6466990d4e4aa793f8343d121e3f93; 267 differing bytes.	Rejected. It reproduces N18 exactly, proving observed definition order does not prevent the unwanted nested inline. All seven siblings remain exact.

Historical hash prefixes are retained where the earlier experiment session did not preserve the complete digest. They uniquely identify the measured output within this ledger; those shapes were not rerun solely to expand a digest.