Re: [Qemu-devel] [RFC] extensions to the -m memory option

[Liviu Ionescu]

> On 02 Jun 2015, at 13:42, Peter Maydell <address@hidden> wrote:
> 
> On 2 June 2015 at 11:32, Peter Crosthwaite <address@hidden> wrote:
>> On Tue, Jun 2, 2015 at 3:15 AM, Liviu Ionescu <address@hidden> wrote:
>>> similar content is also present in Table B3-1 "ARMv7-M address map", in ARM 
>>> DDI 0403D, "ARMv7-M Architecture Reference Manual".
>>> 
>>> 0x00000000-0x1FFFFFFF | Code | Typically ROM or flash memory. Memory 
>>> required from address 0x0 to support the vector table for system boot code 
>>> on reset.
>>> 0x20000000-0x3FFFFFFF | SRAM | SRAM region typically used for on-chip RAM.
>>> 
>> 
>> The Devil is in the "typically" which means it's not actually specced
>> on the processor layer. I think the case is reasonable for your
>> intermediate layer though with a critical mass of vendors opting into
>> this "typical" case.
> 
> Yep. The CPU itself (and the M profile architecture) are opinionated
> about the memory map layout (much more so than A/R profile), but don't
> actually insist on it, and the flash/ROM are outside the core proper.

the  "ARMv7-M Architecture Reference Manual" does not mandate on a specific 
memory type ("Typically ROM or flash memory"), but when it writes "Memory 
required from address 0x0 to support the vector table for system boot code on 
reset.", my understanding is that this is a mandatory requirement.

anyway, my implementation includes a "cortexm-mcu" type, which is intended as 
base type for specific vendor mcu objects, and as such it includes rom and ram.

regards,

Liviu