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Introduction

ELG 6158 Digital Systems ArchitectureMiodrag Bolic

Pipelining• Basic pipeline performance and effects of hazards

on performance• Pipelined version of the MIPS processor• Pipeline hazards

– Structural hazards– Data hazards – Control hazards– Drawing pipeline diagrams to identify hazards and stalls

add $5, $7, $1add $6, $3, $5, sw $6, 200($0)

• Show what parts of the datapath are active and what are the values of control signals and buses for various instruction

Pipelined datapath

Memory HierarchyConcepts of memory hierarchies

– Memory close to the processor is faster, smaller, and more expensive– Take advantage of locality

• Basics of caches– How to access a cache, hit or miss– Determining the size of the byte offset, index, and tags– Determining total number of bits in the cache– Drawing diagrams of different types of caches

• Improving cache performance– Increasing the size of the cache– Increasing the block size– Increasing associativity– Adding a second level cache

Memory Hierarchies

• Virtual Memory– Benefits of virtual memory– Address tranlation processes:

virtual address -> physical address– Page tables– Translation lookaside buffers– Handling page faults

Vector processors• Vector processor architecture• Basic vector processing program• Execution time with and without

chaining for the given architecture

Superscalar processor

• Data dependencies in the program• Superscalar architecture• Understanding terminology: dispatch buffer,

reorder buffer• Execution of programs on superscalar

processors• Show the pipeline activity for the given program

on the given processor

VLIW processor

• VLIW architecture• The role of the compiler • Concept of loop

unrolling and software pipelining

• The example of scheduling of the instructions to the functional units

Dynamic Interconnection Networks

• Properties– Network latency – Hardware complexity– Blocking/Nonblocking

• Switches– Permutations and legitimate states

• Multistage Interconnection networks– Omega network:

» topology, » number of switches, stages and permutations, » routing protocol

• Crossbar

Static Interconnection Networks

• Network properties– Node degree d– Diameter D– Bisection width

• Complete• Star• Tree• Linear array• Ring• Mesh• Torus• Hypercube

– routing protocol

• k-ary n-cubes

• To prepare for dynamic and static interconnection networks use

– slides, – assignment and – text book Chapter 2 and

chapter 3 only text that goes with tables 3.1 and 3.2.

Shared Memory Systems

• Cache coherence policies– Snooping protocols– Directory protocols

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System-on-chip architectures

32-BitNiosProcessor

ROM(with Monitor)

Address (32)

Read

Write

Data In (32)

Data Out (32)

IRQ

IRQ #(6)

Avalon B

us

Nios Processor Tri-StateBridge

SDRAMController

Tri-StateBridge

Compact Flash PIOs

Button PIO7-SegmentLED PIOLCD PIOLED PIO

General Purpose Timer

Periodic Timer

UART

Reconfig PIO

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