RaspberryPi RISC OS on QEmu

I’ve just noticed that there is a QEmu based emulation of the Raspberry Pi that starts up in a Linux environment. Is anybody familiar enough with QEmu and the RISC OS images to know if the emulator could be set to run RISC OS?

I’d be very surprised if RISC OS (or even the official Pi Linux distro) works with the so-called Pi Qemu. Based on my experience with qemu-omap3, very little effort goes into emulating the SoC specific hardware, or even some of the ARM CP15 registers. Basically they just implement the bare minimum to get Linux working, quite possibly using different hardware/drivers than what would be used in a real system.

For the Pi things are even worse than on OMAP, due to the OS’s reliance on the GPU firmware. The GPU processor architecture isn’t publicly documented, so they can’t write an emulator for it. So all the firmware features which Broadcom/the Pi foundation implement in the firmware will then have to be reimplemented manually in Qemu. Unless there are some die-hard Pi Qemu fans out there, I’d be very surprised if the Pi Qemu is emulating nothing more than a generic ARMv6 CPU with generic Qemu hardware.

By the flags being passed to qemu in the launcher script (I had a go to see if RISC OS would work on it the other day – didn’t manage anything more than a black screen sadly), it’s emulating a Versatile PB with ARM 1176.