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Memory model

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Ravi Uday

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Jun 15, 2004, 11:29:15 PM6/15/04
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Hi,

Can anyone tell me what kind of memory model does VxWorks use?
Please cite some examples as to how this works or any pointers to
documents/pdfs...is welcome.

Some pointers on how to write driver using VxWorks will be of great help.

Thanks,
ravi

jamie

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Jun 16, 2004, 6:56:38 AM6/16/04
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Ravi Uday wrote:

Hi ravi,

google >>> vxworks + "memory model"

lots of links.

Jamie

prashanth b s

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Jun 16, 2004, 9:00:02 AM6/16/04
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rav...@yahoo.com (Ravi Uday) wrote in message news:<ecca3ca6.04061...@posting.google.com>...

Hello,
VxWorks5.4 uses a flat addressing model

that is there is no virtual memory

you will not have a user and a super user space .

any space can be accesed from any place i mean task.

so the user should be careful in using the pointers and memory related
issues else the system may crash at any time.

but you can have a separate memory management module attached to your
OS and can be used to manage virtual memory.this comes as a separate
package and we have to buy it from the Wind river

hope i am clear

for documents if you have installed the VxWorks the user manual itself
is very useful.if any one else can help in this it will be better,
since i am using the manual from vxworks which is installed

Prashanth
******************************************************************
P.S: Its not age that counts, its attitude!!!
******************************************************************

rsripathi

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Jun 16, 2004, 2:05:08 PM6/16/04
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The default is a flat memory model (kernel and applications run in the
same space). You could have a virtual memory model if your processor
supports a mmu and you have the vxworks libraries that support the
mmu. I hear that vxworks 5.5 or 6.0 comes with the support to protect
the kernel and the text segment.

I think there is a manual on how to write drivers that comes with your
other manuals. Please refer to it.

HTH,
-Ram

rav...@yahoo.com (Ravi Uday) wrote in message news:<ecca3ca6.04061...@posting.google.com>...

Aditya Amar

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Jun 17, 2004, 4:39:56 PM6/17/04
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As some other people have already pointed out, "plain vanilla" VxWorks
has a flat memory model....which means you can shoot yourself pretty
badly,
if you are not careful.

Read up the arch supplement for whatever processor you use e.g
"VxWorks for PowerPC Architecture supplement"...it should have some
info on the System Memory Layout

Also Appnote-116 by WindRiver provides a good explanation for Heap
management

hth,
Aditya

Ravi Uday

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Jun 22, 2004, 2:33:07 AM6/22/04
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jamie <n...@spam.com> wrote in message news:<MHVzc.28075$7H1.1...@news20.bellglobal.com>...

I read through the BSP call 'intconnect' and have some doubts on the first
parameter (VOIDFUNCPTR * vector)

Since we are using MIPS processor, can i call 'excVecGet(FUNCPTR * vector)'
to get the offset vector pointer so that i can use it when i call 'intconnect'

I really dont know where in the sys initialization ( UsrInit()) does this
vector is being populated and how can i get hold of this initialized pointer

Ex:

FUNCPTR get_vector ()
{

FUNCPTR vtb;

vtb = excVecGet ( vtb );

intconnect( vtb, intThread, 0 );
}

Thx,
Ravi

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