Lecture 2: From Ops to Instructions (ISA)

Background Material

• C programming language.

Reading

• Assembly language - IA32 (Chapter 3 of Bryant and O'Hallaron)
• Gnu Assembly Reference Manual

Topics

• Assembly language - IA32 (Chapter 3 of Bryant and O'Hallaron)
  • Compiling code to produce assembly
  • Viewing object code (objdump and dgb)
  • Registers and address modes
  • Data movement and arithmetic instructions
  • Control structures
  • Procudures, call stack and calling convention
• Analysis of Assembly code
  • Counting instructions (assembly code - performance counters)
  • loop.c
  • Makefile
  • testloop.c
  • timeloop.c
  • countloop.c
  • loop_unopt.s
  • loop_opt.s

Tasks

• Produce and examine the assembly code for loop.c.
• Determine the number of instructions executed in loop.c. as a function of the array size n.
• Time and count instructions for loop.c (optimized and unoptimized) using PAPI
• Determine the number of cycles (and instructions) per iteration for loop.c (optimized and unoptimized) - do a least squares fit to the data produced by PAPI using different values of n.

Lecture Notes

• Lecture slides for chapter 3 of CSAPP.

Resources

• Computer Systems: A Programmer's Perspective
• Gnu Assembly Reference Manual
• IA-32 Instruction set/a>
• PAPI (Performance Application Programming Interface)

Assignments

• In class tasks (not to be handed in)