What This Document Is
This document is a focused instructional resource for Computer Organization (CEG 320) at Wright State University, specifically addressing the critical concept of stack frame management using the LINK assembler directive. It delves into how local variables are handled within subroutines and the implications for program structure, particularly when dealing with recursive functions. The material builds upon foundational assembly language principles and explores techniques for organizing data and code in more complex programs.
Why This Document Matters
This resource is essential for students learning assembly language programming and seeking a deeper understanding of subroutine implementation. It’s particularly valuable when you’re tasked with writing programs that require local variables, or when you need to implement recursive algorithms. Understanding stack frames is fundamental to debugging and optimizing assembly code, and is a key skill for anyone pursuing further study in computer architecture or systems programming. If you're struggling to manage local data within your subroutines, or are confused about how recursion impacts memory usage, this material will provide clarity.
Common Limitations or Challenges
This document concentrates specifically on the *mechanics* of using LINK and UNLK for stack frame management within a 68k assembly environment. It assumes a basic familiarity with assembly language concepts like registers, addressing modes, and subroutine calls. It does not provide a comprehensive introduction to assembly programming itself, nor does it cover alternative methods for managing local variables. It also focuses on conceptual understanding and doesn’t include a complete, runnable program example.
What This Document Provides
* An explanation of how to assemble and link multiple source files.
* Discussion of the challenges associated with managing local variables in subroutines, particularly in relation to recursion.
* A conceptual breakdown of the LINK directive and its effect on the stack pointer and frame pointer.
* Illustrative diagrams to help visualize stack frame allocation and deallocation.
* An examination of how parameters are passed to and from subroutines within the context of a stack frame.
* A detailed look at the UNLK directive and its role in restoring the stack to its original state.
