8 hours ago
- The 1992 game Comanche: Maximum Overkill used a custom DOS extender with expand-down segments for data to catch null pointer accesses, not unreal mode.
- The game refused to work with EMM emulators and crashed with EMM386 active; it also hung or rebooted without HIMEM.SYS due to a substandard DOS extender.
- The game's protected mode entry code (at 1318:0BB5) did not reload segment registers or perform a far jump as Intel recommended, relying on real-mode CS after switching.
- On 386/486 CPUs, CS remained writable in protected mode because real-mode far jumps changed CS access rights to read/write; Pentium and later CPUs ignored rights in real mode, making CS not writable if it had been reloaded in protected mode since reset.