8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 1/31

  Asbinary,whatis11111111 +1

1/26/11 © 2010 Larry Snyder, CSE 1

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 2/31

  StartbycheckingtheProcessingReference

  Whatdoyounoticefromtheirexample?

1/26/11 © 2010 Larry Snyder, CSE 2

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 3/31

  CreateaFontFromUnderTools

1/26/11 © 2010 Larry Snyder, CSE 3

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 4/31

  Pickafont;rememberits

nameandsize!

1/26/11 © 2010 Larry Snyder, CSE 4

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 5/31

  Checkthestepsintheexample

  loadFont();announcefontwithtextFont();use

1/26/11 © 2010 Larry Snyder, CSE 5

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 6/31

1/26/11 © 2010 Larry Snyder, CSE 6

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 7/31

LawrenceSnyderUniversityofWashington,Seattle

© Lawrence Snyder 2004

Remember Back To The Lightbot

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 8/31

  Ourfirstdiscussionof Lightbotnotedthat

theinstructionswere

formedofcompositeoperations…

  Today…weseethatcomputer’s

instructionsare,too

1/26/11 © 2010 Larry Snyder, CSE 8

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 9/31

1/26/11 © 2010 Larry Snyder, CSE 99

  Deterministicallyexecuteinstructionstoprocessinformation

“Deterministically”meansthatwhenacomputer

choosesthenextinstructiontoperformitisrequiredbyitsconstructiontoexecuteaspecificinstruction

basedonlyontheprogramandinputitisgiven

Computers have no freewill and they are not cruel

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 10/31

1/26/11 © 2010 Larry Snyder, CSE 1010

  Computer=instructionexecutionengine▪  Thefetch/executecycleistheprocessthatexecutes

instructions

  Thecomputerinternalpartsimplementthis

cycle

Instruction Fetch (IF)

Instruction Decode (ID)

Data Fetch (DF)Instruction Execution (EX)

Result Return (RR)

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 11/31

1/26/11 © 2010 Larry Snyder, CSE 1111

The Hard Disk is the α-device

Mouse

Keyboard

Scanner 

Hard DiskFloppy Disk

Monitor 

Printer 

SpeakersMemory Output

ALU Control Input

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 12/31

1/26/11 © 2010 Larry Snyder, CSE 1212

  Programsandtheirdatamustbeinthememory

whiletheyarerunning

0

G

1

o

2

D

3

a

4

w

5

g

6

s

7

!

8

!

9

0

10

...

11

0

byte=8 bits

1 0 0 0 1 0 0

memory addressesMemory locations

memory contents

Groups of four

bytes are a word 

Memory Output

ALU Control Input

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 13/31

1/26/11 © 2010 Larry Snyder, CSE 1313

  Fetch/Executecycleishardwiredincomputer’s

control;it’sthe“engine”

The instructions executed have the form

ADDB 20, 10, 16

6

10 11 12 13 14 15

12

16 17 18 19

18

20

...

21

Put in memory location 20 the contents of memory

location 10 + contents of memory location 16

Memory Output

ALU Control Input

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 14/31

1/26/11 © 2010 Larry Snyder, CSE 1414

  Instructionstellwherethedatais,notwhat thedatais…contentschange

One instruction has many effects

ADDB 20, 10, 16

8

10 11 12 13 14 15

7

16 17 18 19

15

20

...

21

60

10 11 12 13 14 15

-55

16 17 18 19

5

20

...

21

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 15/31

1/26/11 © 2010 Larry Snyder, CSE 1515

  Arithmetic/LogicUnitdoestheactualcomputing

Most computers have only about

a 100-150 instructions hard wired

Each type of data has its own separate instructionsADDB : add bytes ADDBU : add bytes unsigned

ADDH : add half words ADDHU : add halves unsigned

ADD : add words ADDU : add words unsigned

ADDS : add short decimal numbers

ADDD : add long decimal numbers

Memory Output

ALU Control Input

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 16/31

1/26/11 © 2010 Larry Snyder, CSE 1616

  Inputunitsbringdatatomemoryfromoutsideworld;outputunitssenddatatooutsideworldfrommemory

▪  Most peripheral devices are “dumb” meaning that

the processor assists in their operation▪  Disks are memory devices because they can

output information and input it back again

Memory Output

ALU Control Input

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 17/31

1/26/11 © 2010 Larry Snyder, CSE 1717

  Theprogramcounter(PC)tellswherethenextinstructioncomesfrom

▪  Instructionsareawordlong,soadd4tothePCtofindthenextinstruction

110 111 112 113 114 115 116 117 118 119 120

...

121

ADD 210,216,220 AND 414,418,720

Program Counter: 112

OR688,724

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 18/31

RunInstruction:2200:Add800,428,884

1/26/11 © 2010 Larry Snyder, CSE 18

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 19/31

1/26/11 © 2010 Larry Snyder, CSE 19

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 20/31

1/26/11 © 2010 Larry Snyder, CSE 20

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 21/31

1/26/11 © 2010 Larry Snyder, CSE 21

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 22/31

1/26/11 © 2010 Larry Snyder, CSE 22

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 23/31

1/26/11 © 2010 Larry Snyder, CSE 23

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 24/31

1/26/11 © 2010 Larry Snyder, CSE 2424

  Therateacomputer“spinsaround”theFetch/Executecycleiscontrolledbyit’s

clock

▪  Currentclocksrun2‐3GHz▪  Inprinciple,thecomputershoulddooneinstruction

percycle,butoftenitfailsto

▪  Modernprocessorstrytodomorethanone

instructionpercycle,andoftensucceed

Clock rate is not a good indicator of speed

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 25/31

1/26/11 © 2010 Larry Snyder, CSE 2525

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 26/31

1/26/11 © 2010 Larry Snyder, CSE 26

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 27/31

1/26/11 © 2010 Larry Snyder, CSE 2727

  Silicon,asemiconductor‐‐sometimesitconductsandsometimesitdoesn’t

▪  It’spossibletocontrolwhensemiconductorsdoanddon’tconduct

Ex.:AND428,884,800

Send “yes” signal on wire

Make semiconductor conduct

if memory location 428 is true

Detect presence/absence of “yes”

Make semiconductor conduct

if memory location 884 is true

Compute by controlling conducting

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 28/31

1/26/11 © 2010 Larry Snyder, CSE 2828

A transistor has 3 wires

ChannelGate

  Chargedobjectsarefamiliar‐‐useanyloncombonadryday

▪  Achargedfieldcancontrolwhether

▪  asemiconductorconductsornot

Thechargeofthecontrolwire(gate)iskey

▪  Neutralgate,channeldoesn’tconduct

▪  Chargedgate,channelconducts

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 29/31

1/26/11 © 2010 Larry Snyder, CSE 2929

  Thefield‐effectideaisimplementedinmetal‐oxide‐semiconductortransistors

  SchematicinSi

Wire Wire

GateInsulator 

Channel

Cross section view View from above

Silicon

Slice across chip, look end on From Above

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 30/31

1/26/11 © 2010 Larry Snyder, CSE 301/26/11 © 2010 Larry Snyder, CSE 30

8/6/2019 Cse120wi11lec10[1] Instruct Execution Parts

http://slidepdf.com/reader/full/cse120wi11lec101-instruct-execution-parts 31/31

1/26/11 © 2010 Larry Snyder, CSE 3131

  Fetch/executecyclerunsinstructions  5stepstointerpretmachineinstructions

  Programsmustbeinthememory

  Dataismovedinandoutofmemory

Instructions, data are represented in binary