Re: [ECOS] Redboot/eCos memory usage

[Gary Thomas <gary at mlbassoc dot com>]

On Sat, 2005-12-03 at 08:20 +0000, R S wrote:
> Confused with eCos/Redboot memory layout structure.
> 
> 1. How can I find how much available memory my target has for eCos applications.
> My target.ld is as below:
> 
> MEMORY
> {
>     vrom : ORIGIN = 0x00000000, LENGTH = 0x00001000
>     ram  : ORIGIN = 0xC0000000, LENGTH = 0x08000000
> }
> 
> 2. How much of the ram is used by redboot? Below is the message I get on
> booting redboot
> 
> RedBoot(tm) bootstrap and debug environment [ROM]
> Non-certified release, version 2.00 - built 11:55:39, May 15 2002
> 
> Platform: BRH (XScale)
> Copyright (C) 2000, 2001, 2002, Red Hat, Inc.
> 
> RAM: 0xc0000000-0xc8000000, 0xc00171e8-0xc7fd1000 available
> FLASH: 0x00000000 - 0x00400000, 32 blocks of 0x00020000 bytes each.
> 
> How is it that the two address ranges overlap??

They don't - the first range indicates the total amount and the 
second range is what's available for user/eCos programs.

> 
> primarily, what I intend to do is reduce my heap size and use the available
> memory to create another memory section. In my application, I used
> mallinfo.arenasize to find initial heap size. It reported over 133MB size??

Are you sure?  I think you are confusing sizes here - 1MB = 1024*1024 
bytes = 1048576 bytes, so your board has 128MB = 134217728 bytes total.

eCos programs can safely use any of the memory from 0xc00171e8 up to
0xc7fd1000 (the lower and upper edge regions are used by RedBoot).

> That appears really huge to me. Is this available for use entirely by eCos
> application or does Redboot uses it too??
> 
> Thanks in advance
> 
> 
-- 
Gary Thomas <gary@mlbassoc.com>


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