CSC362 2004S, Class 28: Stack Frames 

Admin:
* Late: Sam
* Stack frames have another name in the book (Activiation Records)
* Due date for phase 3 extended to a week from Friday
* Extra credit for attending awesome Math talk today
* Cool "humanities" convo tomorrow (no extra credit)

Overview:
* Where we are and where we're going
* What goes in a stack frame
* Layout of stack frames
* Interpreting variable references
* And more as it comes up

Key topics for rest of course will have to do with code generation
(and modification)
* Immediate issue: Where are my variables

Step one: Layout of memory
    +--------+
 0  | CODE   |
    +--------+
    |        |
    |        |
    |        |
    |        |
    |        |
    |        |
    |        |
    +--------+
* Instruction sequences (the code for your program)
* Variables 
  * Global variables (exists throughout the program)
    Available for complete lifetime
    Accessible to all code
  * Local variables 
    Limited scope: Only accessible in certain parts of the program
    When the procedure that owns a local variable terminates, the local variable becomes "garbage"/inaccessible
    * In some languages, local variables maintain their last value (certain kinds of variables in C, all variables in "traditional" fortran)

REMAINDER OF CLASS ON REAL BOARD DUE TO POWER FAILURE