[OpenBIOS] PReP PowerPC "emulation"

Lennart Sorensen lsorense at csclub.uwaterloo.ca
Thu Sep 16 16:34:59 CEST 2010


On Thu, Sep 16, 2010 at 02:50:52PM +0200, Massimo Montecchi wrote:
> So why the QEMU documentation states in this way ?
> 
> Use the executable ‘qemu-system-ppc’ to simulate a complete PREP or PowerMac
> PowerPC system.
> 
> QEMU emulates the following PowerMac peripherals:
> 
>    - - UniNorth or Grackle PCI Bridge
>    - - PCI VGA compatible card with VESA Bochs Extensions
>    - - 2 PMAC IDE interfaces with hard disk and CD-ROM support
>    - - NE2000 PCI adapters
>    - - Non Volatile RAM
>    - - VIA-CUDA with ADB keyboard and mouse.
> 
> QEMU emulates the following PREP peripherals:
> 
>    - - PCI Bridge
>    - - PCI VGA compatible card with VESA Bochs Extensions
>    - - 2 IDE interfaces with hard disk and CD-ROM support
>    - - Floppy disk
>    - - NE2000 network adapters
>    - - Serial port
>    - - PREP Non Volatile RAM
>    - - PC compatible keyboard and mouse.
> 
> QEMU uses the Open Hack’Ware Open Firmware Compatible BIOS available at
> http://perso.magic.fr/l_indien/OpenHackWare/index.htm.
> 
> Since version 0.9.1, QEMU uses OpenBIOS http://www.openbios.org/ for the
> g3beige and mac99 PowerMac machines. OpenBIOS is a free (GPL v2) portable
> firmware implementation. The goal is to implement a 100% IEEE 1275-1994
> (referred to as Open Firmware) compliant firmware.
> 
> The following options are specific to the PowerPC emulation:
> ‘-g WxH[xDEPTH]’
> 
> Set the initial VGA graphic mode. The default is 800x600x15.
> ‘-prom-env string’
> 
> Set OpenBIOS variables in NVRAM, for example:
> 
> 
> qemu-system-ppc -prom-env 'auto-boot?=false' \
>  -prom-env 'boot-device=hd:2,\yaboot' \
>  -prom-env 'boot-args=conf=hd:2,\yaboot.conf'
> 
> These variables are not used by Open Hack’Ware.
> 
> More information is available at http://perso.magic.fr/l_indien/qemu-ppc/.

That is seriously out of date.  It used to be (in 0.9.1 for example)
that the default was to emulate an oldworld PowerMac or a PReP powerpc.
Now the default is to emulate a newworld Mac with openbios (not open
hackware).  I don't know if PReP support is even being maintained anymore,
since no one cares now that newworld Mac support is there.

So wherever that info above was found is almost entirely useless with
current versions of qemu.  Certainly needs a rewrite with current info.

-- 
Len Sorensen



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