CMSC 411 MT Study Guide

Midterm Topic Outline:

• Main components of a computer architecture:
  Compare and contrast:
  • Instruction set architecture
    Why it is modelled independent of machine org.
  • Machine organization
    • 5 major components
    • Relative roles of technological vs. architectural advancements
    • Moore's Law
• Instruction Representation and Semantics
  
• Registers
  • What is a register?
  • What is a register file?
  • How are registers different from regular memory?
  • Difference between "accumulator", "extended accumulator", and "general purpose register" architectures
• Data Representation
  • negative numbers: 2's complement, 1's complement, signed magnitude, bias notation
  • little endian vs big endian
  • Overflow: how to detect for signed arithmetic
• MIPS Instruction Set
  • CISC (e.g. x86) vs. RISC (e.g.: MIPS, ARM)
  • Instruction formats: R, I, J formats
  • Registers
  • What is purpose of register-naming convention?
  • Addressing modes
  • Branching
  • Jumps
  • Common instructions
  • Procedure-calling
    (Not (yet) responsible for parameter-passing conventions)
  • (Not responsible for how linking, loading, executing programs occurs)
• Performance Metrics, Benchmarking
  
  • Different Measures: throughput, response time
  • Interplay between clock rate, cycles/instruction, instruction count
  • Impact of job mix on performance measures
  • How is compiler involved?
  • What are SPEC benchmarks?
  • What is MIPS? Pitfalls? What is "relative MIPS"?
  • Amdahl's Law
  • (Not responsible for power usage impact on design)
• The Arithmetic Logic Unit (ALU)
  
  • You should be able to design a simple 1-bit ALU w/carry-in/-out using gates
  • Cascading 1-bit ALUs into multi-bit ripple-carry ALU
  • Principle of carry lookahead: what are "generate" and "propagate"?
  • Principle of "cascaded carry lookahead": what is it, and why use it?
• Multiplication
  
  • How does hardware multiplication work?
  • What are some optimizations?
  • Booth's algorithm
  • Cascaded ALUs for fast multiplication
  • Tree-structured cascade for even faster multiply
  • MIPS "mul" instruction and HI/LO internal registers
  • Principle of carry lookahead: what are "generate" and "propagate"?
  • Principle of "cascaded carry lookahead": what is it, and why use it?
• Division
  
  • How does hardware division work?
  • What are some optimizations?
  • Why can't we short-circuit division?
  • MIPS "div" instruction and HI/LO internal registers
• Basic Instructions
  • You should be able to give assembly examples of using:
    ADD, ADDI, SUB, LW, SW, BEQ, BNE, J, JAL
• Floating Point
  • IEEE 754 format
  • normalization
  • hidden bit
  • precision vs. magnitude
  • FP math: addition, subtraction, multiplication, division
• Single Cycle Control Path
  • Modelling CPU operation as logical register transfers
  • 5 Steps:
    
    • ISA requirements
    • Datapath component selection
    • Datapath assembly
    • (...other two covered later