Re: [ECOS] ROMRAM startup in arm arch

["Gary D. Thomas" <gary dot thomas at mind dot be>]

On Fri, 2003-01-31 at 10:53, Mark Salter wrote:
> >>>>> Jonathan Larmour writes:
> 
> > Are there any ARM platforms with ROMRAM startup that _don't_ copy it in 
> > the platform HAL?
> 
> > The AT91 seems to only relocate 0x10000 bytes (64K) no matter what which 
> > looks quite odd indeed.
> 
> > The aaed2000, excalibur, ebsa285, as well as edb7xxx and integrator as we 
> > know all seem to copy all ROM.
> 
> > So any reasons for me not to tweak vectors.S to relocate from ROM to RAM 
> > only for ROM startup? And fix the at91 to be consistent with the other 
> > platforms?
> 
> Is there any reason to copy all ROM? Ideally, just copy that part of ROM
> which actually contains something useful.

The code currently (except for the AT91 does so - it just copies
TEXT + RODATA + DATA from ROM/FLASH to RAM.  The problem is that
the initialized DATA stuff is lumped with the RODATA (by the
linking process - at least with the way we've traditionally
laid out the labels) and so it gets copied by the ROM->RAM
relocation and then again by the ROM "initialize DATA from
RODATA" in vectors.S).  It's this "extra" latter copy which
is under consideration.

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