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Stack in salvo

Postby sandhya » Mon Mar 08, 2004 5:59 am

Hi,

We are using PIC18F8620 processor with Salvo RTOS. I am responsibile to come up with a memory model for our system. I am not sure how salvo handles stack. How and where does it stores the register values, and the return addresses when there is an interrupt? How and where does it stire values when the user pushes and pops addresses/ data? Can you please explain me.

sandhya
 
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Location: Erie, PA, USA

Re: Stack in salvo

Postby aek » Mon Mar 08, 2004 7:34 am

The simplest way to explain how Salvo uses the stack on the PIC18 is to say that Salvo's stack usage is the same as that of a typical foreground / background "main loop" application, with an extra 4 bytes (I believe) of stack usage because the tasks are dispatched via a call-by-pointer in Salvo's scheduler, OSSched().

Apart from reviewing the Salvo User Manual and Compiler Reference Manuals, I would recommend that you install Salvo Lite, and then step through a tutorial (say, tu5) in either C or assembly, while watching the SP registers -- that'll give you a clear overview of what it's doing.

Interrupt processing is just like any other application.

If the user is explcitly pushing and popping data, as long as any pushes are undone by pops before the next context switch, then there shouldn't be any impact on Salvo.

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aek
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Re: Stack in salvo

Postby sandhya » Mon Mar 08, 2004 7:44 am

hi,
I am not able to view your reply on "Stack in Salvo" under General Forums
sandhya
 
Posts: 4
Joined: Mon Mar 08, 2004 12:00 am
Location: Erie, PA, USA

Re: Stack in salvo

Postby aek » Mon Mar 08, 2004 8:50 am

Reload the page in your browser?

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