Files
Sylpheed/docs/re/data
sylph-decoder 89d51449e7 re: the A-press fault is SOLVED -- Xenia swallows input, the guest pump is unbounded
The 326 MB log from the failing run was still on disk, so this needed no
emulator time at all.

Mechanism: Xenia's XamInputGetKeystrokeEx returns X_ERROR_SUCCESS with a zeroed
keystroke on every call while a XAM dialog is up (xam_input.cc:197, upstream
Canary). The game's keystroke pump -- sub_82457038, read out of the image -- is
an unbounded 'while (GetKeystrokeEx() == SUCCESS) queue.push_back()'. It queued
8 388 608 empty keystrokes, grew its vector to 64 MB, asked for 128 MB, got a
failed allocation back unchecked, and copied off the top of the guest stack.

Two independent instruments agree to within 7: the Canary counter's last report
before the crash says 8 388 601 swallowed calls; the crash dump's r29 says the
vector held 8 388 608. The reporting granularity is 600.

Retracts this page's own 'r9 is a wild pointer above 4 GB'. Xenia prints
si_addr, a host address; the guest is mapped at 0x100000000, so the fault
address is guest 0x701D0000 -- which is exactly r9 in the register dump.

Also refutes nothing of the port's, but answers its ask #3: the two press-a
captures are different frames (40.84 % of the band's pixels differ at the
best alignment, which has a sharp minimum), so its 0.301 % is not an
instrument floor.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wuu56cE8vJGTBtn1ppsk8v
2026-08-30 06:44:49 +00:00
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