Re: [Qemu-devel] [PATCH 5/7] PPC: Implement e500 (FSL) MMU

[Scott Wood <scottwood@freescale.com>]

On Sat, 7 May 2011 23:36:29 +0200
Alexander Graf <agraf@suse.de> wrote:

> On 07.05.2011, at 00:25, Scott Wood wrote:
> >> +void helper_booke206_tlbsx(target_ulong address_hi, target_ulong address_lo)
> > 
> > What is address_hi?
> > 
> > From gen_tlbsx_booke206() it looks like these two arguments correspond to
> > the two operands, so shouldn't they be added together?  I only see
> > address_lo used.
> 
> Yup. According to the e500 spec:
> 
>   Note that rA = 0 is the preferred form for tlbsx and that some Freescale implementations, such as the e500, take an illegal instruction exception program interrupt if rA!=0.
> 
> So I figured that we're architecturally close enough if we just ignore it for now :).

Architecturally, ignoring it and taking a trap are significantly
different. :-)

In practice it won't matter much, but it seems simple to handle it (why
handle it in tlbivax but not here?), especially if this is to be general
book3e code rather than e500.  I'm still confused about the "address_hi/lo"
naming.

-Scott