Replacement Algorithms

• Least Recently used (LRU)


• e.g. in 2 way set associative
  
  
  
  • Which of the 2 block is lru?
  
  
  
  


• First in first out (FIFO)
  
  
  
  • replace block that has been in cache longest
  
  
  
  


• Least frequently used (LFU)

What is an instruction set?

• The complete collection of instructions that are understood by a CPU


• Machine Code


• Binary


• Usually represented by assembly codes

Elements of an Instruction

• Operation code (Op code)


• Source Operand reference


• Result Operand reference


• Next Instruction Reference

Instruction Cycle State Diagram

Instruction Representation

• In machine code each instruction has a unique bit pattern

Operators and assignments

Using operators - 2

Increment and decrement operators

Two shortcut arithmetic operators are ++, which increments its operand by 1, and --, which decrements its operand by 1.

• ++ increment operator (increments value by 1)


• -- decrement operator (decrements value by 1)

These operators can appear before the operand (prefix) or after the operand (postfix). In the case of the prefix style, the value of the operand is evaluated after the increment/decrement operation. For postfix, the value of the operand is evaluated before the