Add documentation for prj1.asm

readme.md

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+# Project 1
+- You can see this project in action at https://git.unixvoid.com/mfaltys/CSCI-4350
+
+The source code for this project is documented line-by-line but I will
+go over a broad approach here.  
+
+At the time of writing there are 2 functions: main and lookup:
+
+## Main
+The main function takes some user input (for argument 2, the number to be found)
+and stores it into register `$a1` (which is the argument register to send to lookup).
+At the same time we set `$a0` and `$a2` which are the base address of array, and the
+max index of the array to check (respectively).
+When main is returned to after the lookup function it outputs the result
+(either the index where the value is found, or `-1`) and prints it to screen.
+The last thing main does is make the exit syscall to stop the program.  
+
+## Lookup
+The lookup function takes 3 arguments: `$a0`, `$a1`, `$a2` (mentioned above).
+The first thing the function does is make a temporary register with a value equalling
+one more than the maximum array index we will check 
+(this way we can determine if the function is out of bounds).
+We then check for the out of bounds (oob) case and return a `-1` and jump back to where
+we left in main (`$ra`). If we pass the oob check we continue the loop by finding the
+current index in the array and comparing it with the value that was passed to us in `$a1`.
+If we find the proper value we jump back to `$ra` while passing back the index where
+we found it, otherwise we increment the array index counter and loop back to the
+start of the lookup function.  
+
+At the bottom of the program is where we store all our data values (hence the `.data` tag).
+This is where the array and all our messages are to be used in the program.