CS 342 Lecture -*- Outline -*-

* Activation record (AR or frame)
	info needed for a single execution of a procedure

---------------------
	Aho and Ullman's design for Activation Record (using static links):

                     |\\\\\\\\\\\\\\\\\\\\\\\\\	 <____ SP (stack pointer)
		     |			      |
	        TEMP:| 	     temporaries      |
		     |________________________|
		     |                        |
		VAR: |       local data       |
		     |	  (storage for vars)  |
        	     |________________________|
fixed  |        IP:  |   saved machine status |	<_________ EP (env pointer)
size   |	     |	 (ip and other regs)  |
fields |	     |________________________|
       |        SL:  |	     static link      |
       |	     |	     (or display)     |
       |             |________________________|
       |	DL:  |      dynamic link      |
        	     |________________________|
		PAR: |  	              |
		     |    actual parameters   |
                     |  		      |
		     |________________________|
	        RET: |    returned value      |
       	       	     |    (for functions)     |
		     __________________________
---------------------
	*describe reasons for this layout,
		how affected by semidynamic arrays.

	MacLennen's environment part consists of VAR, TEMP, PAR, and SL

	dynamic link (DL): pointer to AR of caller
	parameters and results may be passed in machine registers

** Machine status part (IP)
	does saved part save information about caller or callee?
		-MacLennan: stores information for callee
		-Sebesta, Aho, et al: stores information for caller
			less code
			why?
			-caller can access it on return, with less indirection
			-want to put as much in caller as possible,
				since callee's code is executed for all calls

** Local data storage
	laid out when declarations processed (aggregates laid out contiguously)
	(dynamic arrays kept outside this field)
	at compile time can determine relative address = offset of variables
		(and fields within aggregates)