Re: [Qemu-devel] [Bug 811683] [NEW] 7400, 7410, 7450 cpus vector have wrong exception prefix at reset

[Andreas Färber]

Hi,

Am 16.07.2011 um 23:49 schrieb till:

> I have a proprietary ROM implementing system calls that are executed  
> via
> the 'SC' instruction.
>
> I use qemu-0.14.1,
>
> qemu-system-ppc -M prep -cpu $CPU -bios my_bios -kernel my_kernel
>
> That works fine on a 604 (CPU=0x00040103) - but does not on an  
> emulated 7400 (CPU=0x000c0209) or 7450 (CPU=0x80000201). I found  
> that the emulator jumps to 0x00000c00 instead of 0xfff00c00.
> Probably this is due to a wrong setting in target-ppc/ 
> translate_init.c:
>
> init_excp_604() correctly sets env->hreset_vector=0xfff00000UL;
>
> but
>
> init_excp_7400() says env->hreset_vector=0x00000000UL;
>
> which seems wrong. (the 7400 manual says a hard-reset jumps  
> initializes the
> prefix to 0xfff00000.)

Do you have a link to a spec saying so? Should be trivial to change  
then.

> Likewise, init_excp_7450() (and probably other, related CPUs) are  
> wrong.
>
> Indeed, when I change the value in init_excp_7400() to 0xfff00000UL  
> then
> everything works as expected for me.
>
> ** Affects: qemu
>     Importance: Undecided
>         Status: New

> Bug description:
>  I have a proprietary ROM implementing system calls that are executed
>  via the 'SC' instruction.
>
>  I use qemu-0.14.1,
>
>  qemu-system-ppc -M prep -cpu $CPU -bios my_bios -kernel my_kernel

We are currently in the process of revamping the PReP machine you are  
using above. Is your BIOS available publicly so that we can test we  
don't break anything for you?

Andreas