CPSC 2310 - DAY 21
OCTOBER 24, 2016

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TWO-DIMENSIONAL ARRAYS
----------------------

storage allocation is now more difficult - row major or column major
	 0  1  2
	+--+--+--+
       0|  |  |  |
	+--+--+--+
       1|  |  |  |
	+--+--+--+

(0,0) -+
(0,1)  | row 0
(0,2) -+			ROW MAJOR ORDER
(1,0) -+
(1,1)  | row 1
(1,2) -+


(0,0) -+ column 0
(1,0) -+

(0,1) -+ column 1		COLUMN MAJOR ORDER
(1,1) -+

(0,2) -+ column 2
(1,2) -+

C is row major, while FORTRAN is column major

MULTIPLE ENTRY POINTS
---------------------

Multiple entry points allow different function names, different parameter lists
different parameters, etc.

fn_ab:
	mov r0, #1	//default first parameter
fn_b:
	mov r1, #2	//default second parameter

fn:
sum:
	add r0, r0, r1	//add parameters and return sum
bx lr

PASS BY VALUE
-------------

	.Use of the parameter without needing to load it from memory.
	
PASS BY REFERENCE
-----------------

	.Must first load the value from memory (equiv. to dereferencing)
	before using it.

SEPERATE ASSEMBLY
-----------------

	.seperate source files provide a nice structure for dividing a project
	among team members

	.minimize the work of reassembly and relinking when change occurs
	in only one source file

	.prewritten libraries provide machine extensions (ex. square root)

*** by using gcc -Wall -c first.c, this means compile and don't link ***
*** allows you to compile and test the syntax of one file, is not executable ***

PROGRAM TESTING
---------------

	.BOTTOM-UP DEVELOPMENT
		.write and test the lowest-level (leaf) subroutines first,
		then write the modules or program that uses them
		
		.requires extra effort of writing drivers

	.TOP-DOWN DEVELOPMENT
		.write the highest level functions first and test the logic

		.requires extra effort of writing stub routines that
		are placeholders for lower level subroutines