Simulators for computer architecture classes

Anastas MisevMarjan Gusev

http://twins.ii.edu.mk/

The need● Computer architecture is a foundational

subject for the entire CS education● Learning computer architecture can be

frustrating if left in theory● Visualization explains the architectural

concepts in more acceptable way to the students

● Using visual simulators is becoming an irreplaceable element in CS education

● Simulators makes the devices more the accessible

The simulators● Different products available● Development of own tools● Student projects● Most important

– SuperSim2 – a visual PostRISC simulator– Tomasulo – web based visual simulator of the

popular algorithm– Scoreboard – visual and configurable

simulator for the scoreboard algorithm– 8051 simulator– VDD for an external programmable device

● The advantages of home production

SuperSim 2.0● User code, pseudo assembler● Syntax checking, error indication● Extensive configuration● Simulation varying from simple RISC to

advanced PostRISC ● Step by step execution● Visualization of the pipeline● Non visual mode for high performance● Vast logging capabilities for performance

analysis● Detailed statistics

Code editor

● Editing● File management● Syntax check

RISC runtime

● Basic features● One pipeline● Registers● Data cache

Configuration 1

● Execution units– Number and type

● Rates– Issue– Dispatch

Configuration 2

● Usage of shelving● Reservation

stations– Type– Size

Configuration 3

● Usage of register renaming

● Number of registers

● Access

Configuration 4

● Usage of out-of-order

● Reorder buffer– Size

Configuration 5

● Usage of branch processing

● Speculation● Static and

dynamic● Explicit and

implicit● Global

PostRISC runtime

● Pipeline stages● Animated

instruction flow● Step-by-step

execution● Superscalar

features

ROB

● Sequential consistency

● Circular buffer– Head– Tail

● Instructions by stage

Registry file

● Architecture registers

● Rename registers– Mapping– Value– Latest

● Visualizes 32+32 registers

Branch tables

● Explicit prediction– BHT

● Implicit prediction– BTAC

● Global 2-bit

Data cache

● 1024 locations● Word addressible● To be extended

to multilevel

Statistics

● Detailed statistics– Usage %– IPC per stage– Prediction– Renaming– Memory

dependencies– ...

SuperSim 2.0

● Visualy explains ILP concepts

● Configurable ● Programmable● Easy to use and

students like it

http://twins.ii.edu.mk/supersim/

Tomasulo

• Student project• Web based• Highly graphical• Configurable• Self explanatory• 1-1 mapping of the

tables used

Scoreboard

• Also students project

• Windows application

• Fully configurable• Can run user code• Animated or step-

by-step execution• Configurable

operation latencies

8051 simulator

• 8031/8051 simulator

• Student project• Includes– IDE– Code highlighting – Debugging– Step-by-step

execution

• Modular design

Virtual Device Driver• Student project• Replaces a single external ISA device (8255

based)• Used for I/O assembler programming classes• Uses windows VDD and a front end application

as I/O

Conclusion● The simulators used in several courses

covering computer architecture● Students interest and motivation is

much higher● “One device per student” environment● Motivation to continue the

development of new tool, mainly as student projects