The following guidelines are expected for all homework submissions:

• All homework must be typed. Homework which is not typed will be returned ungraded and will be subject to the late homework guidelines as set out on the syllabus page. PLEASE DO NOT scribble something on lined paper and rip it out of your spiral notebook — hanging chads went out with the presidential election in 2000.
• I don't care too much about what font you use or how large your margins are; however, you might want to check out a monospaced font for typing code, as it will be easy to see the indentations.
• Speaking of indenting, PLEASE DON'T USE TABS TO INDENT YOUR CODE. Tabs can often get interpreted differently by different computers and applications, and could make code that is nicely formatted on your computer look all over the map on my computer or printer. USE SPACES INSTEAD. You can set up almost every modern text editor to insert spaces whenever you press the TAB key, or you can simply pound the spacebar.
• Work with a partner. I can't stress this enough; part of this policy is don't split up the work – WORK TOGETHER on the assignment; DO NOT DIVIDE UP THE WORK!. Doing assignments this way mimics an industry code development model called pair programming which is part of the Extreme Programming [Agile] software development method. Feel free to collaborate in your pairs as much as you want, doing the entire assignment together. Only submit ONE copy for the both of you.
• DO NOT share your work between groups. Doing so will count as plagiarism. If you wish to discuss solutions with another group over coffee in the Lair, that's fine as long as it is kept at the conceptual and you don't share your code between groups. Each group needs to turn in its own version of the solutions.
• Repeat: you only need to turn in one copy per group.
• Submit your homework through GitHub, in your repository, and be sure to make me a contributor so I have access. I cannot evaluate what I cannot see! If I can't upload to your repo, you will not get an evaluation for the assignment.

Problems for Assignment #1

Learning Outcomes: 1) Verifying the development environment is set up properly for GitHub; 2) Verifying the development environment is set up and is functional for compiling C programs; 3) Verifying the development environment is set up and is functional for assembling nasm programs; 4) Verifying that the instructor can access the GitHub repository to provide feedback evaluations during the semester

This homework assignment simply extends the in-class assignment for week one. In classwork01 you set up and compiled a simple C program to make sure it worked. This proved the gcc compiler and linker is working on your computer. It also makes sure your editor is working properly so that you can create source code with it. These are basic steps, but I want to make sure everyone is on equal footing from the start of the semester.

The second part of this homework is to verify that your nasm assembler is working properly, which is also part of the classwork01 exercise.

Part One

1. Add to your sayhello.c program from your week01.html in class exercise to prompt the user for their name from the terminal command line, using the printf() and the gets() functions. These are also demonstrated in the F to C conversion code on the week01.html page. Don't forget you will need to include BOTH the stdio.h and stdlib.h header files in your source file, just like you need to do in Java using the "import" keyword:

          #include <stdio.h>
          #include <stdlib.h>
   
          // main method and code go here...
                       

2. Add more lines to your program to change the Hello, World! message to say Hello, followed by the name that the user has input
3. Compile and run your program to make sure everything works
4. Test your program with several different inputs, like dog, $237.19, and just pressing enter without entering anything. See if you can break your program and make it crash!
5. Go to GitHub and set up your repo and submission structure if you haven't already done so; make it look like the structure that is on the instructor's repo at this link.
6. Upload and commit your completed sayhello.c file to your repo under the classwork/classwork01 folder.
7. For a little extra challenge, see if you can dress up your program a bit by making it output some extra blank lines before and after the output. Can you make your program indent the output away from the left margin of the window?
8. Commit all your code so far to your repo to make sure you've captured your properly working code.

Part Two

1. Download and install the nasm assembler from this location using the version that is appropriate for your operating system. For MacOS, use the macosx version. You'll need to download the zip file and do the installation manually. Once that is done, verify that you can access it from your command line by running the command:

         nasm
                       

   
   
2. Create a new file called sayhello.asm in the same directory where your sayhello.c is located.
3. Edit the file and paste in the following code:
   

   Mac OS version [uses Mac system calls]
   

            global      start                   ; on Linux this should be "_start"
   
            section     .text
   start:   mov         rax, 0x02000004         ; system call for write [Linux should be "_start"]
            mov         rdi, 1                  ; file handle 1 is stdout
            mov         rsi, message            ; address of string to output
            mov         rdx, 13                 ; number of bytes
            syscall                             ; invoke operating system to do the write
            mov         rax, 0x02000001         ; system call for exit [Linux use "60"]
            xor         rdi, rdi                ; exit code 0
            syscall                             ; invoke operating system to exit
   
            section     .data
   message: db          "Hello, World", 10
                       

   
   
   Windows version [uses C library's 'printf' function]
   

            global      _main                   ; declares the starting entry point
            extern      _printf                 ; we'll use the "C" library for now
   
            section .text                       ; code starts here
   _main:   push        message                 ; put the message on the stack
            call        _printf                 ; call "printf()" to display it
            add         esp, 4                  ; set up the exit
            ret                                 ; return to Windows
   
   message: db  "Hello, World!", 10, 0
                       

4. Assemble, link, and run with the following command:
   

   Mac OS version [updated]
   

         nasm -fmacho64 sayhello.asm && ld -macosx_version_min 10.7 sayhello.o -o sayhello2 && ./sayhello2
   
         [NOTE: this is a different command than the original, using the linker instead of gcc]
         you can also use semicolons to separate commands:
   
         nasm -fmacho64 sayhello.asm;ld -macosx_version_min 10.7 sayhello.o -o sayhello2;./sayhello2
         note the semicolons        ↑                                                   ↑
   
                       

   
   
   Windows version
   

         nasm -fwin32 sayhello.asm && gcc sayhello.obj -o sayhello2.exe && sayhello2
                       

5. NOTE that the last part of the commands shown above will run your program, but you can also run it by just entering that last part. On Mac, run using ./sayhello and on Windows run using sayhello. If there are errors, do some Internet searching to see if you can track down what's going on. If you can't get some help from your friendly prof or a TA from the Keck Lab in Discord.
6. Now that you have both the C and nasm versions working, see if you can figure out how to do the same dressing up of your assembler code, putting extra blank lines before and after the text output. Feel free to search the Internet for help. [Hint: check the message label in the code for clues!]
7. When everything is working, be sure to commit your code to your repo!