From Code to 1010

There are only absolutes in the digital world

  • Everything is stored in bits
  • 1 = on, 0 = off

Integers

Integers

Float values

Machine Code

  • CPU instructions

2 main language types

  • Interpreted
  • Compiled

Compiled

  • Needs to be "compiled" before execution
  • Compilation - Turns source code into machine code
  • Examples
    • C/C++
    • Go
    • C#
    • Java
    • JavaScript

Compiled

  • Compile Time Errors
  • Compile Time Optimizations
  • Must recompile every change before running

Interpreted

  • Translated at execution, one statement at a time
  • Examples
    • Ruby
    • Python
    • PHP
    • C#
    • Java
    • JavaScript

Interpreted

  • Run Time Errors
  • Hard to optimize at run time
  • Can re-run after saving source code
  • Needs a special library to run

Were you paying attention?

  • C#
  • Java
  • JavaScript

These languages are compiled and interpreted

  • Compiled into what is commonly called Bytecode
  • Bytecode is Just In Time compiled

What happens when we run the code?

  • Interpreted code gets parsed and is executed 
    • May be executed directly
    • May run through a Virtual Machine
  • Compiled code gets executed
    • May be linked against OS libraries

Virtual Machine?

  • Provides a platform agnostic set of instructions
    • Platform? OS X, Windows, Linux, iOS
  • Virtual Machines are compiled for a specific platform

Major Archtecture Type

  • Complex Instruction Set Computing (CISC)
    • x86, VAX, PDP-11
  • Reduced Instruction Set Computing (RISC)
    • ARM, SPARC, Power PC, MIPS

CISC

  • Try to create a high level language for the processor
  • Each instruction could use multiple memory cycles
  • Operations are memory based

RISC

  • Fewer memory cycles per instruction
  • Some implementations have larger instruction set than CISC
  • Operations are Register based

CISC vs RISC

 

CISC

MULT 2:3, 5:2

 

RISC

LOAD A, 2:3
LOAD B, 5:2
PROD A, B
STORE 2:3, A

Questions?

Made with Slides.com