Re: [Qemu-devel] [PATCH v1 1/1] target_arm: Make the reset rom_ptr a property

[Peter Maydell]

On 21 August 2014 14:15, Christopher Covington <address@hidden> wrote:
> On 08/21/2014 08:33 AM, Peter Maydell wrote:
>> I think the ELF loading thing is a separate issue -- if we're loading
>> an ELF file we should honour its entry point address instead of
>> trying to load from the vector table. (The question of what we
>> do about SP is an interesting one...)
>
> In my experience with A-profile, software is expected to either know enough
> about the platform to set the SP to something sane itself or make the
> SYS_HEAPINFO semihosting call, which despite the name returns both stack and
> heap information.

My point was that M profile is significantly different from
A profile here. In A profile on CPU reset only the PC is
set to a known value, and therefore any bare metal code
that gets run will always set up SP itself in some way.
In M profile, on CPU reset both PC and SP are read from
the vector table, and so it's reasonable to have bare
metal code for M profile whose entry point assumes that
SP has been initialized.

-- PMM