Fall 2014 SPO600 Assembly Language Presentation

Assignment

1. Select one of the topics below by placing your name in the "Student" column (first come, first served).
2. During week 3, research the topic and prepare a 3- to 5-minute presentation to teach the answer to the class.
3. Be prepared to teach this presentation during week 4. You may want to draw whiteboard diagrams, use presentation slides, or have a 1-page handout. Please avoid taking more than 5 minutes in total for your presentation.

FAQ

• Q: How much detail should the presentation include?
  • A: Each of these topics is pretty small and straightforward. Provide enough detail that your colleagues in this course will know what they need to know going forward -- the focus is practical knowledge necessary to understand, modify, and write code. Where appropriate, provide some type of resource for future reference -- a link to an existing web resource, a 1-page handout, or a blog post or wiki page about the topic.

• Q: How will this be marked?
  • A: In week 4, I will ask you to write a short blog post summarizing your presentation.

• Q: What about the topics not selected by a student?
  • A: Feel free to grab a second topic if you're interested. I'll teach the unclaimed topics.

• Q: Can we work with others preparing our topic?
  • A: Yes. In many cases, one topic is complimentary to another topic, and it would be great if you coordinated on your presentations.

• Q: What resources should I use?
  • A: There are resources on this wiki and on the web (for example, see the Assembly Language category on this wiki). However, the definitive answer to many of these questions will come from the architecture reference manuals for each architecture, or the documentation for the tools. Here are some links to get you started:
    • GAS Manual - Using as, The GNU Assembler: https://sourceware.org/binutils/docs/as/
    • ARM Aarch64 documentation
      • Instruction Set and Software Developer Manual: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.genc010197a/index.html
      • Procedure Call Reference: http://infocenter.arm.com/help/topic/com.arm.doc.ihi0055b/IHI0055B_aapcs64.pdf
    • x86 CPU Instruction Set and Software Developer Manuals
      • AMD: http://developer.amd.com/resources/documentation-articles/developer-guides-manuals/
      • Intel: http://www.intel.com/content/www/us/en/processors/architectures-software-developer-manuals.html
    • x86 Assembler Web sites
      • http://ref.x86asm.net/
      • http://sandpile.org/

Topics

Topic	Question/Topic Description	Student
x86 Registers	What are the names and sizes of all of the x86_64 registers? Why are they named this way? Which ones have special significance, unusual operation, or are required for specific operations?
Aarch64 Registers	What are the names and sizes of all of the Aarch64 registers? Why are they named this way? Which ones have special significance, unusual operation, or are required for specific operations?
Absolute addressing and Immediate values on Aarch64	In Aarch64 systems, the size instruction is limited to 64 bits. Since some bits are required to encode the operation, addressing mode, and registers, the number of bits available to specify an address or immediate value (constant) are limited. What are the limitations? How can you work around these limitations?
NASM Syntax	What is NASM, and what are the basic rules of NASM syntax? How do you use preprocessor directives (such as #include and #define) or equivalent?
GNU x86_64 gas Syntax	What are the basic rules of GNU Assembler (gas) syntax for x86_64 platforms? How do you use preprocessor directives (such as #include or #define) or equivalent?
GNU aarch64 Syntax	What are the basic rules of GNU Assembler (gas) syntax for aarch64 platforms? How do you use preprocessor directives (such as #include or #define) or equivalent?
Argument storage on x86_64	When a function/procedure is called on an x86_64 Linux system, where are the arguments stored? What if there are many arguments?
Argument storage on aarch64	When a function/procedure is called on an aarch64 Linux system, where are the arguments stored? What if there are many arguments?
System call numbers on x86_64	What are the system call numbers on an x86_64 Linux system? Where are they defined and how do you use them?
System call numbers on aarch64	What are the system call numbers on an aarch64 Linux system? Where are they defined and how do you use them?
PLT	In an ELF file, what is a PLT and how is it used? When does an ELF file not contain a PLT?
Assembling using gas	How do you use the GNU assembler (gas) to compile an assembly-language program ("assemble" it) from the command line?
Single-stepping with gdb	How do you execute a program one instruction at a time (single-stepping) using the GNU debugger (gdb)? How do you view register contents between steps?
Dividing integers on x86_64 and aarch64	How do the division instructions work on x86_64 and aarch64? How are they different? What are the advantages of each?
Static and dynamic linking	What are the differences between static and dynamic linking? Advantages of each from the point of view of performance, resource utilization, and security?
The Mysterious XOR	x86 and x86_64 code often contains instructions that XOR a register with itself (e.g., xor %eax,%eax). What does this do and why is it used? What is the equivalent in Aarch64?