Digital System Lec 21?

Starting from Blocks and Mapping FUnctions, Slide 25

Direct Mapping Pros and Cons

Simple and Efficient, but Not Optimal

Associative Mapping

Place a block from main memory in cache. Each block is 16 bits.

Set Mapping Associative

Direct to set number, but associative to set.

Every set has 2 Blocks.

Why is Set associative Mapping better

It’s associative, the only thing complex about it is the search for the tag.

LRU Alg

Block not used for the longest period of time, or potentially the future.

Counter is only used in

non random LRU Alg

Full Adder

Add two bits of same weight with a carry in bit, and produces a sum bit and carry out bit

Ripple Carry Adder

A Chain of n FA Stages linked by carry bits, can add two n bit integers. It’s called ripple carry because carry must propogae (HE SWITCH SLDIES)