Re: SID and eCos

[Scott Dattalo <scott at dattalo dot com>]

On Tue, 18 Jun 2002, Scott Dattalo wrote:

> 
> I'm trying to use SID to simulate an ARM processor. When I build a "hello 
> world" example and try to simulate it, I get this:
> 
> $ arm-elf-sid hello
> loader: write to data accessor failed at address 0x2020000, status 2
> loader: error loading hello

I think I answered my question.

The Makefile I used to create the executable is part of eCos. I 
specifically target Atmel's AT91EB40 evaluation board. The generic, out of 
the box, SID arm emulation knows nothing about an AT91EB40. The error 
reported above is telling me that the executable accesses RAM that doesn't 
exist (hey, I think I like that:).  So I added a few --memory-region's:

$ arm-elf-sid --cpu=arm --memory-region=0x2020000,0x20000 
--memory-region=0xfffe0000,0x1ffff --gdb=2000 -EL hello

And that worked! 

So now it looks like I have not one, but two (mostly) independent ways to 
simulate my source. I like the SID approach because of the added 
flexibility; specifically the ability to profile.

----

As an aside...

sid appears to be an extraordinarily powerful tool. Is there any reason 
why it's not more popular? Judgeing from the mailing list archives, it 
appears that not too many people are using it.

As another asided, I'm the primary author the GNUPIC Simulator, gpsim.  
This is a GPL'd simulator of Microchip PIC microcontrollers. The homepage
is: http://www.dattalo.com/gnupic/gpsim.html . The GNUPIC tool chain does
not use gcc/binutils - instead we emulate Microchip's tool chain and I'm
porting to SDCC (Small Device C Compiler). However, I'm going to
investigate to what extent it's possible to leverage our two projects.
Specifically, I'd like to incorporate the abstract hardware interface that
sid supports with gpsim.  And to reciprocate, I can add some of gpsim's
modules to sid!

Scott