Cesarus85--mjolnir-vr/docs/object_matching_logs/libcmt_cfin_obj.md

libs/libcmt/cfin.obj exact-match ledger

This atomic lane starts at campaign commit 08f86f9b. Before editing, cfin.obj was MISSING at config index 656, unparked, absent from all refs, logs, and worktrees, and cleared against every active peer claim.

Plain-English behavior and provenance

_fltin2 converts a decimal C string into the CRT's encoded double result. It records how many bytes were consumed and translates three parser outcomes—no digits, overflow, and underflow—into the flags expected by formatted input.

The primary provenance is obj\i386\cfin.obj from the authentic XDK 3911 libcmt.lib (archive SHA-256 60aa4c87c97eeb6662b31d9d37cf3caba1afabaec72c47b090e7a0ce8b632f55; member SHA-256 086449a89357ab11903fa8a0de9218da0095792e5122ee7eee25ce0852ba16f9). Its CodeView names Microsoft source d:\xbox-finalfre\private\sdktools\crt\fpw32\conv\cfin.c and compiler ID 0x001c2426. The public Xbox source is pinned at Git blob 6d722d94a5a50abf80b6586477f68ee67035cbcb; its matching internal type definitions are pinned at blobs 09e8ca9500638a15144c2dfb534e2e4e79dba64d and 971e0166e136b26061b18f96785f3a2f410b2529.

The archive member is strict-identical to January before reconstruction: one 133-byte _fltin2 function, two REL32 relocations (___strgtold12 at +29 and __ld12tod at +65), normalized SHA-256 0d0ab166e005e1e23f55b0afc554f32cd06d89b881491d01010a02e969d27ff7, and no runtime data.

Measured source shapes

ID	One changed factor	Strict result	Decision
E01	Faithful control flow, but represent the temporary as a C double and assign 0.0	130/133 bytes, 2/2 relocs; VC7 emitted fldz/fstp and needed only two saved registers	Rejected: the authentic source explicitly avoids x87 exceptions while copying/zeroing the representation
E02	Preserve the same readable control flow, but model the double as two named 32-bit representation words, including its ABI alignment slot	133/133 bytes, 2/2 exact relocs, identical normalized SHA	Accepted

The word representation is semantic, not byte forcing: Microsoft's own source states that it copies a DOUBLE wrapper rather than executing floating-point instructions specifically to avoid raising IEEE exceptions.

Validation and house/Berth audit

• XDK 3911 CL 13.00.9254.1 used unchanged /O1 /Gy flags.
• Hardened coff_compare reports all_equal: true; no aliases or data owners exist in this object.
• Full-build, progress/semantic, regression, admission, and test results are recorded after the final clean commit/rebase.
• The source uses named status enums, checked structure layout, vertical prototypes, and ordinary readable C. It contains no assembly, volatile, forced inline/noinline, undefined aliasing, byte patch, flag change, comparator exception, or waiver. The explicitly named representation words preserve an intentional original behavior, not a bug; no behavioral bug was found that needs a fix note.