Due date: See Class Webpage

0. Preparations

• To do this project, you must obtain a copy of the prepared files with these commands:

  mkdir ~/cs255/pj9 cp /home/cs255001/Handouts/pj9/* ~/cs255/pj9

1. Assignment (overview)

Write a recursive InsertList function in the program file InsertList.s that maintains a sorted list in ascending order.

The List structure is as follows:

class List { int Value; <--- list elements ordered by this value List Next; }

More details of the assignment are given below.

2. The InsertList function:

The InsertList() function has the following prototype in a high level programming language (such as Java):

List InsertList(List head, List elem) { ... }

The parameters are as follows:

The parameter head contains the reference (= address) of the first element in the linekd list The parameter elem contains the reference (= address) of the list element that must be inserted into the list that starts at head

The InsertList() function must return the address of the first element of the new list (= the list with the element inserted)

(I.e.: the parameters and the return value have the same meaning as the Insert() function discussed in this web page: click here

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Requirement:

The InsertList function must be recursive The InsertList function receives the parameters on the stack passed in the following manner: // Call head = InsertList(head, elem) movw r0, #:lower16:elem movt r0, #:upper16:elem ldr r0, [r0] // r0 = value in elem push {r0} // Pass elem as 2nd param movw r0, #:lower16:head movt r0, #:upper16:head // r0 = addr of head ldr r0, [r0] // r0 = value in head push {r0} // Pass head as 1st param bl InsertList add sp, sp, #8 // Pop parameters The InsertList function must return the new list in: register r0           The function must maintain an ordered linked list. In other words: when you insert a new element with some value x into the list, make sure you maintain the correct ordering of list elements by their values stored inside the list element. The ordering maintained is asscending order in value variable of the list elements (i.e., the value variables in the list elements increases as you traverse the list).

Develop your algorithm first

• Unlike the other projects, in this one you need to develop your algorithm.

  You should write a recursive InsertList function in Java first. When you have tested the function in Java, you can then implement it in ARM assembler

  I have written a skeletal Java program that you can use to develop your recursive list insert algorithm. You should have copied this file in the preparation step above.

  Use the file HelpList.java in your project directory and write a recursive InsertList( ) method in Java. You can compile and run the HelpList.java program and make sure that your InsertList( ) method in Java is correct first before you write your program in ARM assmbler - because debugging assembler code is much harder than Java code.

  If the InsertList( ) algorithm is correct, the output of the HelpList.java program is:

  List = 30 List = 30 50 List = 10 30 50 List = 10 30 40 50 List = 10 20 30 40 50

3. The pj9.s test program

I have created a test program that calls the InsertList function.

You can use this program test your project.

After you can written your InsertList function, you can compile the project using this command:

/home/cs255001/bin/as255 pj9.s InsertList.s

Use Egtapi to run the pj9 program.

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Correct behavior of the InsertList project:

When pj9 starts, you will first need to click on the list window in the variable display area: This will show the list window that contain the prepared list variables elem and head variables. The ordered list is found at the head variable. The elem variable is used to allocate and insert new list elements When you click on Run (in Egtapi), the program will stop at the break point Check1 At this moment, you should see the listing window: The program is ready to insert the first list element The list display area will still show an empty list: When you click on Run a 2nd time, the program will stop at the break point Check2: At this moment, you should see the list with the element (30) at head: When you click on Run a 3rd time, the program will stop at the break point Check3: At this moment, you should see the list with the element (30, 50) at head: When you click on Run a 4th time, the program will stop at the break point Check4: At this moment, you should see the list with the element (10, 30, 50) at head: When you click on Run a 5th time, the program will stop at the break point Check5 At this moment, you should see the list with the element (10, 30, 40, 50) at head: When you click on Run a 6th time, the program will stop at the break point Stop and you see the final list: You may have to scroll the list display window a little down to see the list

4. Break point

• I did not put any break point at InsertList.

  Because if I do, then the program will stop each time it recurses That will take too long to run a correct program....

• So if your function crash, you should:

  Add a break point at InsertList (so you will stop when the function recurses) Add labels to locations in your InsertList function where you suspect an error and: .global the label Recompile the project Add a break point at that label Preferably, save the breakpoint location for later use.

5. Turn in

Turn in your program InsertList.s as pj9 using the turnin command (executed while you're in your cs255 directory)

Open EGTAPI's Terminal and type these command into the bottom terminal window:

cd ~/cs255/pj9 /home/cs255001/turnin InsertList.s pj9 // If you're in section 1 or /home/cs255002/turnin InsertList.s pj9 // If you're in section 2

You can also use the Turnin button in EGTAPI to turn in:

Click on InsertList.s in the File Browser Click Turnin (below the Compile button) A window will pop up. In this window: Select your section number Enter turn Project code pj9 Click Turn-in Make sure you see the message: Program `.....InsertList.s' has been successfully turned in by yourNetID as pj9. Otherwise, your project has not been turned in successfully

As usual, I want the source (so I can read it). DO NOT turn in the executable or the object code !

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• Extension request
  • To request an extension for pj9, you must execute the following command in the EGTAPI Terminal before the deadline of the homework:

    /home/cs255001/req-ext pj9 // If you're in section 1 or /home/cs255002/req-ext pj9 // If you're in section 2

    You request will be successful if you have not exceeded the maximum number of "free" (no-questions-asked) requests allowed