The fake disc ID homebrew gets when it has no PARAM.SFO is built from the sum of
the bytes of its folder name, summed through a plain char - which is signed on
x86 and unsigned on ARM. So the same homebrew folder produced one ID on Windows
and a different one on Android, quietly splitting its savestates and per-game
config between platforms. Sum through unsigned char, which is what the ARM
builds (Android, iOS, Apple Silicon) already did.
Uppercasing is now explicit and ASCII-only rather than toupper(). Passing a
negative char to toupper() is undefined and trips MSVC's debug CRT assert, so a
folder with a non-ASCII name could stop a debug build dead, and what it did with
bytes above 0x7F otherwise depended on the locale.
ASCII folder names - very nearly all of them - produce exactly the same ID as
before. Non-ASCII ones change on the signed-char platforms, to what the
unsigned-char ones were already generating.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GZq8ZtJmFY7bkX5FVkr3P9
