Mihai Parparita 049f8b68c5 machines: repeat 4 MB ROM in 16 MB mapped space ...

Per the Hammerhead ERS the ROM region is 0xFF000000-0xFFFFFFFF. We were
only mapping the ROM at the uppermost 4 MB of that (0xFFC00000). The fact
that copies are returned at other addresses in that range is not
explicitly stated in the ERS, but it does appear to be emprically true.
It's also corroborated by the 9600 wiring diagram, which shows only enough
address bits for 4MB being used for the ROM.

Also does the same fix for Platinum/7200, which has the same mapping and
address bits, and adds some notes about this to the documentation.

Fixes SheepShaver in BeOS guests, which was using 0xFF000000 to get at
the hardware ROM (see https://github.com/cebix/macemu/blob/96e512bd6376e78a2869f16dcc8a9028bce5ee72/BasiliskII/src/BeOS/SheepDriver/sheep_driver.c#L454).

2026-10-14 15:46:43 -07:00

..

developers

machines: repeat 4 MB ROM in 16 MB mapped space

2026-10-14 15:46:43 -07:00

users

main: allow realtime mode to be enabled at startup

2026-10-08 17:56:05 -07:00