Every conclusion that named EulerAngles::operator=(const LinearMatrix&) as the
fault site was wrong, including the disassembly built on top of it. Three
independent proofs:
1. ROTATION.CPP is ours, so the function was instrumented directly -- print
this, &matrix and a local's address on the first twelve calls plus any wild
pointer. The run faulted with ZERO [euler] lines: never called.
2. After the probe was added, 0x66D9 disassembles to a two-byte conditional
jump (jnl) that touches no memory. The dump reports ErrCode 0004, a data
READ.
3. EIP 0x66D9 and cr2 0x7000FA64 are identical to the byte across every build
this session, including builds where the code at that offset changed
completely. A fault in our CODE segment moves when the code moves. This
one does not -- it lives in the DPMI host, which loads low and never gets
relinked.
The map lookup was a coincidence: our _TEXT is section-relative from 0, so its
offsets overlap the host's low addresses, and the map will name a function for
any small number. Before resolving a fault address against the map, confirm it
belongs to our segment -- cheapest check is whether it moves on relink.
What is actually true, by same-binary A/B:
vRIO DOWN, serial1 still a namedpipe -> mission LAUNCHES
vRIO UP, same conf, same binary -> FAULT
The trigger is a LIVE RIO stream, not an unplugged cable. The emulator reports
continuous serial1 RX overruns, the fault lands wherever the app happened to be
(terrain one run, the mech's inside view another), and the shipped binary
survives the identical conditions. A fault at a fixed host address, at
arbitrary points in the app, requiring an interrupt-driven stream, is an
interrupt re-entrancy signature rather than a wild pointer.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
CydandClaude Fable 5
3c42766f48
