# Stack frame structure

**URL:** <https://forums.digi.com/t/stack-frame-structure/11951>\
**Category:** Rabbit Software\
**Tags:** stack\
**Created:** [September 17, 2013, 2:04pm UTC](https://forums.digi.com/t/stack-frame-structure/11951 "2013-09-17T14:04:01Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![RickMcDonald](https://avatars.discourse-cdn.com/v4/letter/r/b5ac83/32.png) [@RickMcDonald](https://forums.digi.com/u/RickMcDonald)\
**Post date:** [September 17, 2013, 2:04pm UTC](https://forums.digi.com/t/stack-frame-structure/11951/1 "2013-09-17T14:04:01Z")

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I notice whenever a auto variable or parameter are referenced on the stack in mixed assembly, the form is SP+@SP+X. That implies to me that X would be a negative offset if it is referencing an auto, and a positive offset when referencing a parameter. Is this a correct assumption?

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**Author:** ![trooper2](https://avatars.discourse-cdn.com/v4/letter/t/edb3f5/32.png) [@trooper2](https://forums.digi.com/u/trooper2)\
**Post date:** [September 24, 2013, 2:24pm UTC](https://forums.digi.com/t/stack-frame-structure/11951/2 "2013-09-24T14:24:00Z")

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I am no assembly expert but there are two great resources that I can recommend.

One is the instruction set manual itself [http://ftp1.digi.com/support/documentation/0190098\_l.pdf](http://ftp1.digi.com/support/documentation/0190098_l.pdf) and the other is a book written by Larry Cicchinelli called Assembly Language Essentials.