Re: [ECOS] Porting eCos to DDB-VRC4375(Memory mapping)

["Ling Su" <lingsu at palmmicro dot com>]

Sorry, I checked out the newest CVS version, I found it is correct. So
following question is invalid. :)

Rgds,
-Ling
----- Original Message -----
From: "Ling Su" <lingsu@palmmicro.com>
To: "Nick Garnett" <nickg@cygnus.co.uk>
Cc: <ecos-discuss@sources.redhat.com>
Sent: Tuesday, January 30, 2001 11:42 AM
Subject: Re: [ECOS] Porting eCos to DDB-VRC4375(Memory mapping)


> Dear Nick,
>
> Thanks a lot for you helpful explaination! I found it is not consistent
for
> the mlt_mips_vr4300_vrc4373_rom.ldi, mlt_mips_vr4300_vrc4373_rom.mlt, and
> mlt_mips_vr4300_vrc4373_rom.h. Supposely the *.ldi and *.h are both
> generated by *.mlt, right? but in in mlt_mips_vr4300_vrc4373_rom.ldi and
> mlt_mips_vr4300_vrc4373_rom.h, we can find the ram ORIGIN is 0x80000200
> LENGTH is 0x7fe00. Any particular reason for this? I am a little bit
> confused.
>
> Regards,
> -Ling
>
>
> >
> > <2>. In the mlt_mips_vr4300_vrc4373_rom.ldi,
> > MEMORY
> > {
> >     ram: ORIGIN = 0x80000800, LENGTH = 0x7F800
> >     rom: ORIGIN = 0xBFC0000, LENGTH = 0x80000
> > }
> > I don't quite understand the ram LENGTH setting, why we just use 512KB
ram
> > in rom start up setting? Can we set the ram LENGTH to larger. Another
> thing
> > is why its ORIGIN is 0x80000800?
>
> Again, the RAM length is probably just left over from an earlier
> version of the code. Generally we use the ROMRAM startup for all
> VRC4373 non-RAM configurations, I suspect that the ROM startup has not
> been used for a long time and has not been kept up to date.
>
> The RAM starts at 0x80000800 because we have various tables defined to
> go into low RAM. Below 0x80000400 there are hardware defined interrupt
> vectors. We have the VSR table at 0x80000400 and the vector table at
> 0x80000600.
>
>
>
>