FIT1047 Lecture Notes - Lecture 3: Master Boot Record, Register File, Binary Number
31 May 2018
School
Department
Course
Professor
Week 3
Wednesday, 14 March 2018
1:06 PM
CPU - Central Processing Unit
• Built out of logic gates
• Executes instructions
Programming languages cannot be executed directly by CPU. They are compiled or interpreted.
We take human language and compile it into something the CPU understands. (Compiled means
translate)
CPU can only execute machine code.
Machine Code
• Very simple
• Different for each type of CPU architecture (smartphones are very different to laptop)
o Both can run python and java because it can be translated into different machine codes
• Programs = sequence of instructions
o Stored in memory
o Each instruction is encoded into one or more words
Instruction Set Architecture (ISA) is the instructions that a particular type of CPU understands.
• Does some maths (adds, subtract, multiple, compare)
o Arithmetic
• Move data between memory, CPU and Input/output (I/O)
o Pressing keys on keyboard
• Control how CPU executes conditionals and loops
Marie
Very basic machine architecture
• 16 bit words
• 16 different instructions
o Likely only need 10 or 12
• One general purpose register (similar to variable in programming)
• Instructions are composed of an opcode (4 bits) and an address (12 bits)
A register is a storage cell for temporary data.
• A bit of memory inside CPU
• AC register (accumulator): a "general purpose" register
o Works with data inside the CPU
Assembly language
Machine code is hard to read and write (1's and 0's)
• It is the human language of machine code
• Translates 1:1 into machine code
• One mnemonic per machine instruction
Marie Instructions
Load X - 0001
Store X = 0010
Add X - 0011
find more resources at oneclass.com
find more resources at oneclass.com
Subt X - 0100
Halt X - 0111
Skincond - 1000
Jump X - 1001
Ex.
Load 3
Add 4
Halt
DEC 10
DEC 100
//ALU = Arithmetic Logic Unit
https://marie-js.github.io/MARIE.js/
Combinational Circuit
Output is a function of the inputs
Only does half the job
Can only be used to add 2 bits together; cannot add 3 bits together
find more resources at oneclass.com
find more resources at oneclass.com
