cdc+++ author = “Winston Tsia” authorlink = "" title = “Computer Organization Systems Programming” date = 2023-01-23T00:30:07-08:00 description = “Notes on Computer Organization and Systems Programming” tags = [ “tag1”, “tag2”, ] categories = [ “cat1”, “cat2”, ] math = true notaxonomy = false images = ["/img//example.jpg"] imagetext = “An example text for an image you could add!” hidden = true norobots = true nodate = true hidemeta = false +++

Contents

• Contents
• CPU Architecture
  • Arithmetic Logic Unit
• Bits, Bytes, and Integers
• Assembly x86
  • Basics
    • C++ vs Assembly:
      • C++
      • Assembly
    • Data Representation
• C Programming
  • Memory Hierarchy
    • SRAM vs DRAM
    • ROM: Read-Only Memory
    • Nonvolatile vs Volatile Memory
    • Bus
    • Memory Systems
      • Disk Drive
      • PCI vs PCI Express Bus
      • Process of DMA: Direct Memory Access

CPU Architecture

Comprised of the ALU, Control Unit, Clock, and Memory Registers

Arithmetic Logic Unit

Bits, Bytes, and Integers

Bits are stored as 0 or 1.

Bytes are 8 bits.

Integers

Assembly x86

Basics

C++ vs Assembly:

C++ has limitations if it uses certain libraries on a single operating system. Assembly is not portable. They are designed for specific processor families (Motorola 68x00, x86, SUN Sparc, Vax, and IBM-370). Language may be translated during execution in a processor by a microcode interpreter.

C++

int Y;
int X = (Y + 4) * 3;

Assembly

Example program:

mov  eax,Y   ; move Y to the EAX register
add  eax,4   ; add 4 to the EAX register
mov  ebx,3   ; move 3 to the EBX register
imul ebx     ; multiply EAX by EBX
mov  X,eax   ; move EAX to X

• linkers vs assemblers: assemblers compile the s.c. programs from assembly into machine instruction, linkers are a utility program that combine individual files made by assemblers into an executable program
• virtual machine: a software program that emulates the functions of some physical or virtual computer

Data Representation

C Programming

Memory Hierarchy

SRAM vs DRAM

• Static vs Dynamic Random-Access-Memory
  • volatile–does not maintain data when powered off

ROM: Read-Only Memory

• Erasable, E-Erasable, Programmable, Flash Memory

Nonvolatile vs Volatile Memory

Nonvolatile: ROMS, maintains data when powered off

Bus

wires that carry address data/control signals

• memory operations involving the bus take longer

Memory Systems

• register operations in the CPU are sub nanoseconds

Disk Drive

• made of platters that form cylinders, with tracks containing sectors separated by gaps
• recording zone: disjoint subsets of the track/sectors
  • capacity = average recording zone $$ Capacity = byte/sector * sector/track * \track/surface * surface/platter * platter/disk $$

PCI vs PCI Express Bus

• Express is point-to-point, whereas PCI is broadcast

Process of DMA: Direct Memory Access

CPU -> Controller -> Disk -> Load to Main Memory -> Controller sends signal to CPU