Chapter 02 Computer Organization and Design, Fifth Edition: The Hardware/Software Interface (The...

8/17/2019 Chapter 02 Computer Organization and Design, Fifth Edition: The Hardware/Software Interface (The Morgan Kaufmann Series in Computer Architecture and Design) 5th Edition

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COMPUTER ORGANIZATION AND DThe Hardware/Software Interface

5thEdition

Chap er 2

Instructions: Languageof the Computer


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Chapter 2 — Instructions: Language of the Computer — 2

Instruction Set

The repertoire of instructions of acomputer Different computers have different

instruction sets But with many aspects in common

Early computers had very simpleinstruction sets Simplified implementation

Many modern computers also have simpleinstruction sets

§2!Introductio n


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The MIPS Instruction Set

"sed as the e#ample throu$hout the %oo& Stanford MI'S commerciali(ed %y MI'S

Technolo$ies )wwwmipscom* +ar$e share of em%edded core mar&et

,pplications in consumer electronics- networ&/stora$ee.uipment- cameras- printers-

Typical of many modern IS,s

See MI'S 0eference Data tear1out card- and ,ppendi#es B and E

http://www.mips.com/http://www.mips.com/


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Arithmetic Operations

,dd and su%tract- three operands Two sources and one destination

add a, b, c # a gets b + c

,ll arithmetic operations have this form Design Principle 1: Simplicity favours

re$ularity

0e$ularity ma&es implementation simpler Simplicity ena%les hi$her performance at

lower cost

§22peratio

n softhe3omp

uterHa

rdware


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Arithmetic !amp"e

3 code4f = (g + h) - (i + j);

3ompiled MI'S code4

add t0, g, h # temp t0 = g + hadd t1, i, j # temp t1 = i + jsub f, t0, t1 # f = t0 - t1


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Chapter 2 — Instructions: Language of the Computer — #

$egister Operan%s

,rithmetic instructions use re$ister operands

MI'S has a 52 6 521%it re$ister file "se for fre.uently accessed data

7um%ered 8 to 5! 521%it data called a 9word:

,ssem%ler names ;t8- ;t!- - ;t< for temporary values

;s8- ;s!- - ;s= for saved varia%les Design Principle 2: Smaller is faster

cf main memory4 millions of locations

§25perand

s ofthe3ompu

terHar d

ware


7/93Chapter 2 — Instructions: Language of the Computer — &

$egister Operan% !amp"e

3 code4f = (g + h) - (i + j); f- - > in ;s8- - ;s?

3ompiled MI'S code4add $t0, $s1, $s2add $t1, $s3, $s4sub $s0, $t0, $t1


8/93Chapter 2 — Instructions: Language of the Computer — '

Memor( Operan%s

Main memory used for composite data ,rrays- structures- dynamic data

To apply arithmetic operations +oad values from memory into re$isters Store result from re$ister to memory

Memory is %yte addressed Each address identifies an @1%it %yte

Aords are ali$ned in memory ,ddress must %e a multiple of ?

MI'S is Bi$ Endian Most1si$nificant %yte at least address of a word c.f. +ittle Endian4 least1si$nificant %yte at least address


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Chapter 2 — Instructions: Language of the Computer — )

Memor( Operan% !amp"e *

3 code4g = h + A!"; $ in ;s!- h in ;s2- %ase address of , in ;s5

3ompiled MI'S code4 Inde# @ re.uires offset of 52

? %ytes per word

$t0, 32($s3) # %ad %&dadd $s1, $s2, $t0

offset %ase re$ister


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Chapter 2 — Instructions: Language of the Computer — *+

Memor( Operan% !amp"e 2

3 code4A12" = h + A!"; h in ;s2- %ase address of , in ;s5

3ompiled MI'S code4 Inde# @ re.uires offset of 52

$t0, 32($s3) # %ad %&dadd $t0, $s2, $t0s $t0, 4!($s3) # st%&e %&d


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Chapter 2 — Instructions: Language of the Computer — **

$egisters ,s- Memor(

0e$isters are faster to access thanmemory peratin$ on memory data re.uires loads

and stores More instructions to %e e#ecuted

3ompiler must use re$isters for varia%lesas much as possi%le nly spill to memory for less fre.uently used

varia%les 0e$ister optimi(ation is important


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Chapter 2 — Instructions: Language of the Computer — *2

Imme%iate Operan%s

3onstant data specified in an instructionaddi $s3, $s3, 4 7o su%tract immediate instruction

Cust use a ne$ative constantaddi $s2, $s1, -1

Design Principle 3: Ma&e the commoncase fast Small constants are common Immediate operand avoids a load instruction


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The Constant .ero

MI'S re$ister 8 );(ero* is the constant 8 3annot %e overwritten

"seful for common operations

E$- move %etween re$istersadd $t2, $s1, $'e&%


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/nsigne% 0inar( Integers

iven an n1%it num%er 8

8!

!2n

2n!n

!n 2#2#2#2## ++++= −

−

−

−

0an$e4 8 to 2n F ! E#ample

8888 8888 8888 8888 8888 8888 8888 !8!!2G 8 !625 8622 !62! !628

G 8 @ 8 2 ! G !!!8

"sin$ 52 %its 8 to ?-2


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2s1Comp"ement Signe% Integers

iven an n1%it num%er 8

8!

!2n

2n!n

!n 2#2#2#2## ++++−= −

−

−

−

0an$e4 F2n F ! to 2n F ! F ! E#ample

!!!! !!!! !!!! !!!! !!!! !!!! !!!! !!882G F!625! !6258 !622 862! 8628

G F2-!?=-?@5-?@ 2-!?=-?@5-?? G F?!8

"sin$ 52 %its F2-!?=-?@5-?@ to 2-!?=-?@5-?=


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Chapter 2 — Instructions: Language of the Computer — *#

2s1Comp"ement Signe% Integers

Bit 5! is si$n %it ! for ne$ative num%ers 8 for non1ne$ative num%ers

F)F2n F !* canJt %e represented

7on1ne$ative num%ers have the same unsi$nedand 2s1complement representation Some specific num%ers

84 8888 8888 8888

F!4 !!!! !!!! !!!! Most1ne$ative4 !888 8888 8888 Most1positive4 8!!! !!!! !!!!


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Chapter 2 — Instructions: Language of the Computer — *&

Signe% egation

3omplement and add ! 3omplement means ! K 8- 8 K !

#!#

!!!!!!!!## 2

−=+

−==+

E#ample4 ne$ate 2

2 G 8888 8888 88!82 F2 G !!!! !!!! !!8!2 !

G !!!! !!!! !!!82


18/93 §


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Chapter 2 — Instructions: Language of the Computer — *)

$epresenting Instructions

Instructions are encoded in %inary 3alled machine code

MI'S instructions Encoded as 521%it instruction words

Small num%er of formats encodin$ operation code)opcode*- re$ister num%ers-

0e$ularity

0e$ister num%ers ;t8 F ;t= are re$Js @ F ! ;t@ F ;t< are re$Js 2? F 2 ;s8 F ;s= are re$Js ! F 25

§20epresen

tin$Instruction

sinthe

3omputer


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Chapter 2 — Instructions: Language of the Computer — 2*

$1format !amp"e

add $t0, $s1, $s2

special ;s! ;s2 ;t8 8 add

8 != !@ @ 8 52

888888 !888! !88!8 8!888 88888 !88888

888888!888!!88!88!88888888!888882 G 8252?828!

op rs rt rd shamt funct %its %its %its %its %its %its


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e!a%ecima"

Base ! 3ompact representation of %it strin$s ? %its per he# di$it

8 8888 ? 8!88 @ !888 c !!88

! 888! 8!8! < !88! d !!8!

2 88!8 8!!8 a !8!8 e !!!8

5 88!! = 8!!! % !8!! f !!!!

E#ample4 eca@ ?28 !!!8 !!88 !8!8 !888 8!!8 8!88 88!8 8888


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MIPS I1format Instructions

Immediate arithmetic and load/store instructions rt4 destination or source re$ister num%er 3onstant4 F2!I to 2!I F ! ,ddress4 offset added to %ase address in rs

Design Principle 4: ood desi$n demands $ood

compromises Different formats complicate decodin$- %ut allow 521%itinstructions uniformly

eep formats as similar as possi%le

op rs rt constant or address %its %its %its ! %its


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Store% Program Computers

Instructions represented in%inary- >ust li&e data

Instructions and data storedin memory

'ro$rams can operate onpro$rams e$- compilers- lin&ers-

Binary compati%ility allows

compiled pro$rams to wor&on different computers Standardi(ed IS,s

The BIG Pic ure

§


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Logica" Operations

Instructions for %itwise manipulationperation 3 Cava MI'S

Shift left NN NN s

Shift ri$ht LL LLLs&

Bitwise ,7D O O ad, adi

Bitwise 0 P P %&, %&i

Bitwise 7T Q Q %&

"seful for e#tractin$ and insertin$$roups of %its in a word

§2+o$ical

perations


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Chapter 2 — Instructions: Language of the Computer — 2#

Shift Operations

shamt4 how many positions to shift

Shift left lo$ical Shift left and fill with 8 %its s %y i %its multiplies %y 2i

Shift ri$ht lo$ical Shift ri$ht and fill with 8 %its s& %y i %its divides %y 2i )unsi$ned only*

op rs rt rd shamt funct

%its %its %its %its %its %its


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Chapter 2 — Instructions: Language of the Computer — 2&

A Operations

"seful to mas& %its in a word Select some %its- clear others to 8

ad $t0, $t1, $t2

8888 8888 8888 8888 8888 !!8! !!88 8888

8888 8888 8888 8888 88!! !!88 8888 8888

;t2

;t!

8888 8888 8888 8888 8888 !!88 8888 8888;t8


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Chapter 2 — Instructions: Language of the Computer — 2'

O$ Operations

"seful to include %its in a word Set some %its to !- leave others unchan$ed

%& $t0, $t1, $t2

8888 8888 8888 8888 8888 !!8! !!88 8888

8888 8888 8888 8888 88!! !!88 8888 8888

;t2

;t!

8888 8888 8888 8888 88!! !!8! !!88 8888;t8


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Chapter 2 — Instructions: Language of the Computer — 2)

OT Operations

"seful to invert %its in a word 3han$e 8 to !- and ! to 8 MI'S has 70 51operand instruction

a 70 % GG 7T ) a 0 % *%& $t0, $t1, $'e&%

8888 8888 8888 8888 88!! !!88 8888 8888;t!

!!!! !!!! !!!! !!!! !!88 88!! !!!! !!!!;t8

0e$ister 84 alwaysread as (ero

§2


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Chapter 2 — Instructions: Language of the Computer — 3+

Con%itiona" Operations

Branch to a la%eled instruction if acondition is true therwise- continue se.uentially

be &s, &t, *1 if )rs GG rt* %ranch to instruction la%eled +!R

be &s, &t, *1 if )rs G rt* %ranch to instruction la%eled +!R

j *1 unconditional >ump to instruction la%eled +!

2=Instructio

n sforMa&in$D

ecision

s


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Compi"ing Loop Statements

3 code4

hie (sa/ei" == ) i += 1;

i in ;s5- & in ;s- address of save in ;s

3ompiled MI'S code4*%%p s $t1, $s3, 2 add $t1, $t1, $s $t0, 0($t1)

be $t0, $s, it addi $s3, $s3, 1 j *%%pit .


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0asic 0"ocs

, %asic %loc& is a se.uence of instructionswith 7o em%edded %ranches )e#cept at end* 7o %ranch tar$ets )e#cept at %e$innin$*

, compiler identifies %asic%loc&s for optimi(ation

,n advanced processorcan accelerate e#ecutionof %asic %loc&s


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More Con%itiona" Operations

Set result to ! if a condition is true therwise- set to 8

st &d, &s, &t

if )rs N rt* rd G !R else rd G 8R sti &t, &s, c%stat

if )rs N constant* rt G !R else rt G 8R

"se in com%ination with be- best $t0, $s1, $s2 # if ($s1 $s2)be $t0, $'e&%, * # b&ach t% *


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Signe% ,s- /nsigne%

Si$ned comparison4st

-sti

"nsi$ned comparison4 stu- stui E#ample

;s8 G !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! ;s! G 8888 8888 8888 8888 8888 8888 8888 888! st $t0, $s0, $s1 # siged

F! N ! ⇒ ;t8 G !

stu $t0, $s0, $s1 # usiged ?-2


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Proce%ure Ca""ing

Steps re.uired

! 'lace parameters in re$isters

2 Transfer control to procedure

5 ,c.uire stora$e for procedure

? 'erform procedureJs operations

'lace result in re$ister for caller

0eturn to place of call

2@Supportin

$'roceduresi n

3omp

uterHard

ware


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$egister /sage

;a8 F ;a54 ar$uments )re$Js ? F =* ;v8- ;v!4 result values )re$Js 2 and 5* ;t8 F ;t


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Leaf Proce%ure !amp"e

3 code4

it eaf5eampe (it g, h, i, j)6 it f; f = (g + h) - (i + j);

&etu& f;7 ,r$uments $- - > in ;a8- - ;a5

f in ;s8 )hence- need to save ;s8 on stac&* 0esult in ;v8


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Leaf Proce%ure !amp"e

MI'S code4eaf5eampe addi $sp, $sp, -4 s $s0, 0($sp)

add $t0, $a0, $a1 add $t1, $a2, $a3 sub $s0, $t0, $t1 add $/0, $s0, $'e&% $s0, 0($sp) addi $sp, $sp, 4 j& $&a

Save $s0 on stack

Procedure body

Restore $s0

Result

Return


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on1Leaf Proce%ures

'rocedures that call other procedures

Vor nested call- caller needs to save onthe stac&4 Its return address ,ny ar$uments and temporaries needed after

the call

0estore from the stac& after the call

f


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on1Leaf Proce%ure !amp"e

3 code4

it fact (it )6if ( 1) &etu& f;

ese &etu& 8 fact( - 1);7 ,r$ument n in ;a8

0esult in ;v8

L f P % "


44/93


on1Leaf Proce%ure !amp"e

MI'S code4fact addi $sp, $sp, -! # adjust stac f%& 2 items s $&a, 4($sp) # sa/e &etu& add&ess s $a0, 0($sp) # sa/e a&gumet sti $t0, $a0, 1 # test f%& 1

be $t0, $'e&%, *1 addi $/0, $'e&%, 1 # if s%, &esut is 1 addi $sp, $sp, ! # p%p 2 items f&%m stac j& $&a # ad &etu&*1 addi $a0, $a0, -1 # ese dec&emet

ja fact # &ecu&si/e ca

$a0, 0($sp) # &est%&e %&igia $&a, 4($sp) # ad &etu& add&ess addi $sp, $sp, ! # p%p 2 items f&%m stac mu $/0, $a0, $/0 # mutip9 t% get &esut j& $&a # ad &etu&

L " t th St


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Loca" ata on the Stac

+ocal data allocated %y callee e$- 3 automatic varia%les

'rocedure frame )activation record* "sed %y some compilers to mana$e stac& stora$e

M L t


46/93


Memor( La(out

Te#t4 pro$ram code Static data4 $lo%al

varia%les e$- static varia%les in 3-

constant arrays and strin$s ;$p initiali(ed to address

allowin$ Woffsets into thisse$ment

Dynamic data4 heap E$- malloc in 3- new in

Cava

Stac&4 automatic stora$e

Ch t t

§2


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Character ata

Byte1encoded character sets ,S3II4 !2@ characters


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0(te6a"f7or% Operations

3ould use %itwise operations

MI'S %yte/halfword load/store Strin$ processin$ is a common case

b &t, %ffset(&s) h &t, %ffset(&s)

Si$n e#tend to 52 %its in rt

bu &t, %ffset(&s) hu &t, %ffset(&s)

Xero e#tend to 52 %its in rt

sb &t, %ffset(&s) sh &t, %ffset(&s)

Store >ust ri$htmost %yte/halfword

St i C "


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String Cop( !amp"e

3 code )naYve*4 7ull1terminated strin$

/%id st&cp9 (cha& ", cha& 9")6 it i;

i = 0; hie ((i"=9i"):=


50/93


String Cop( !amp"e

MI'S code4st&cp9 addi $sp, $sp, -4 # adjust stac f%& 1 item s $s0, 0($sp) # sa/e $s0 add $s0, $'e&%, $'e&% # i = 0*1 add $t1, $s0, $a1 # add& %f 9i" i $t1

bu $t2, 0($t1) # $t2 = 9i" add $t3, $s0, $a0 # add& %f i" i $t3 sb $t2, 0($t3) # i" = 9i" be $t2, $'e&%, *2 # eit %%p if 9i" == 0

addi $s0, $s0, 1 # i = i + 1 j *1 # et ite&ati% %f %%p

*2 $s0, 0($sp) # &est%&e sa/ed $s0 addi $sp, $sp, 4 # p%p 1 item f&%m stac j& $&a # ad &etu&

32 8it C t t§2


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8888 8888 8!!! !!8! 8888 8888 8888 8888

3218it Constants

Most constants are small !1%it immediate is sufficient

Vor the occasional 521%it constant

ui &t, c%stat 3opies !1%it constant to left ! %its of rt 3lears ri$ht ! %its of rt to 8

hi $s0, 1

8888 8888 8!!! !!8! 8888 !88! 8888 8888%&i $s0, $s0, 2304

!8MI'S,d

dressin$for52

1BitIm

mediates

and

,ddres

ses

0 h A%% i


52/93


0ranch A%%ressing

Branch instructions specify pcode- two re$isters- tar$et address

Most %ranch tar$ets are near %ranch Vorward or %ac&ward

op rs rt constant or address

%its %its %its ! %its

'31relative addressin$ Tar$et address G '3 offset 6 ? '3 already incremented %y ? %y this time

9 A%% i


53/93


9ump A%%ressing

Cump )j and ja* tar$ets could %eanywhere in te#t se$ment Encode full address in instruction

op address

%its 2 %its

)'seudo*Direct >ump addressin$

Tar$et address G '35!2@ 4 )address 6 ?*

T t A%% i "


54/93


Target A%%ressing !amp"e

+oop code from earlier e#ample ,ssume +oop at location @8888

*%%p s $t1, $s3, 2 @8888 8 8 !< < ? 8

add $t1, $t1, $s @888? 8 < 22 < 8 52

$t0, 0($t1) @888@ 5 < @ 8

be $t0, $s, it @88!2 @ 2! 2

addi $s3, $s3, 1 @88! @ !< !< !

j *%%p @8828 2 28888

it . @882?

0 hi A


55/93


0ranching ar A7a(

If %ranch tar$et is too far to encode with!1%it offset- assem%ler rewrites the code

E#ample

be $s0,$s1, *1

Z

be $s0,$s1, *2j *1

*2 .

A%%ressing Mo%e Summar(


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A%%ressing Mo%e Summar(

S(nchroni;ation§2!


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S(nchroni;ation

Two processors sharin$ an area of memory '! writes- then '2 reads Data race if '! and '2 donJt synchroni(e

0esult depends of order of accesses

Hardware support re.uired ,tomic read/write memory operation 7o other access to the location allowed %etween the

read and write

3ould %e a sin$le instruction E$- atomic swap of re$ister [ memory r an atomic pair of instructions

!!'arallelis

mandInstruc

tions4S

ynchroni(ation

S(nchroni;ation in MIPS


58/93


S(nchroni;ation in MIPS

+oad lin&ed4 &t, %ffset(&s) Store conditional4 sc &t, %ffset(&s)

Succeeds if location not chan$ed since the 0eturns ! in rt

Vails if location is chan$ed 0eturns 8 in rt

E#ample4 atomic swap )to test/set loc& varia%le*t&9 add $t0,$'e&%,$s4 ;c%p9 echage /aue

$t1,0($s1) ;%ad ied

sc $t0,0($s1) ;st%&e c%diti%a be $t0,$'e&%,t&9 ;b&ach st%&e fais

add $s4,$'e&%,$t1 ;put %ad /aue i $s4

Trans"ation an% Startup§2!


59/93


Trans"ation an% Startup

Many compilers produceo%>ect modules directly

Static lin&in$

!2Translati

n$andStartin

$

a'ro

$ram

Assem8"er Pse %oinstr ctions


60/93

Chapter 2 — Instructions: Language of the Computer — #+

Assem8"er Pseu%oinstructions

Most assem%ler instructions representmachine instructions one1to1one

'seudoinstructions4 fi$ments of theassem%lerJs ima$ination

m%/e $t0, $t1 K add $t0, $'e&%, $t1

bt $t0, $t1, * K st $at, $t0, $t1be $at, $'e&%, *

;at )re$ister !*4 assem%ler temporary

Pro%ucing an O8


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Chapter 2 — Instructions: Language of the Computer — #*

Pro%ucing an O8


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Chapter 2 — Instructions: Language of the Computer — #2

Lining O8


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Loa%ing a Program

+oad from ima$e file on dis& into memory

! 0ead header to determine se$ment si(es

2 3reate virtual address space

5 3opy te#t and initiali(ed data into memory r set pa$e ta%le entries so they can %e faulted in

? Set up ar$uments on stac&

Initiali(e re$isters )includin$ ;sp- ;fp- ;$p*

Cump to startup routine 3opies ar$uments to ;a8- and calls main Ahen main returns- do e#it syscall


64/93

La;( Linage


65/93


La;( Linage

Indirection ta%le

Stu%4 +oads routine ID-Cump to lin&er/loader

+in&er/loader code

Dynamicallymapped code

Starting 9a,a App"ications


66/93

Chapter 2 — Instructions: Language of the Computer — ##

Starting 9a,a App"ications

Simple porta%leinstruction set for

the C\M

Interprets%ytecodes

3ompiles%ytecodes of9hot: methods

into nativecode for host

machine

C Sort !amp"e§2!5


67/93

Chapter 2 — Instructions: Language of the Computer — #&

C Sort !amp"e

Illustrates use of assem%ly instructionsfor a 3 %u%%le sort function

Swap procedure )leaf*/%id sap(it /", it )

6 it temp; temp = /"; /" = /+1";

/+1" = temp;7 v in ;a8- & in ;a!- temp in ;t8

5,3

Sort

E#ampleto'u

t

It,ll

To$ether

The Proce%ure S7ap


68/93

Chapter 2 — Instructions: Language of the Computer — #'

The Proce%ure S7ap

sap s $t1, $a1, 2 # $t1 = 8 4

add $t1, $a0, $t1 # $t1 = /+(84) # (add&ess %f /")

$t0, 0($t1) # $t0 (temp) = /"

$t2, 4($t1) # $t2 = /+1"

s $t2, 0($t1) # /" = $t2 (/+1")

s $t0, 4($t1) # /+1" = $t0 (temp)

j& $&a # &etu& t% caig &%utie

The Sort Proce%ure in C


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Chapter 2 — Instructions: Language of the Computer — #)

The Sort Proce%ure in C

7on1leaf )calls swap*

/%id s%&t (it /", it )6 it i, j; f%& (i = 0; i ; i += 1) 6

f%& (j = i 1; j >= 0 ?? /j" > /j + 1"; j -= 1) 6 sap(/,j); 7 77

v in ;a8- & in ;a!- i in ;s8- > in ;s!

The Proce%ure 0o%(


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Chapter 2 — Instructions: Language of the Computer — &+

The Proce%ure 0o%( m%/e $s2, $a0 # sa/e $a0 it% $s2

m%/e $s3, $a1 # sa/e $a1 it% $s3

m%/e $s0, $'e&% # i = 0f%&1tst st $t0, $s0, $s3 # $t0 = 0 if $s0 @ $s3 (i @ )

be $t0, $'e&%, eit1 # g% t% eit1 if $s0 @ $s3 (i @ )

addi $s1, $s0, 1 # j = i 1

f%&2tst sti $t0, $s1, 0 # $t0 = 1 if $s1 0 (j 0)

be $t0, $'e&%, eit2 # g% t% eit2 if $s1 0 (j 0)

s $t1, $s1, 2 # $t1 = j 8 4

add $t2, $s2, $t1 # $t2 = / + (j 8 4)

$t3, 0($t2) # $t3 = /j"

$t4, 4($t2) # $t4 = /j + 1"

st $t0, $t4, $t3 # $t0 = 0 if $t4 @ $t3

be $t0, $'e&%, eit2 # g% t% eit2 if $t4 @ $t3

m%/e $a0, $s2 # 1st pa&am %f sap is / (%d $a0)

m%/e $a1, $s1 # 2d pa&am %f sap is j

ja sap # ca sap p&%cedu&e

addi $s1, $s1, 1 # j = 1

j f%&2tst # jump t% test %f ie& %%p

eit2 addi $s0, $s0, 1 # i += 1

j f%&1tst # jump t% test %f %ute& %%p

'ass

paramsO call

Moveparams

Inner loop

uter loop

Inner loop

uter loop

The u"" Proce%ure


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Chapter 2 — Instructions: Language of the Computer — &*

s%&t addi $sp,$sp, 20 # mae &%%m % stac f%& &egiste&s

s $&a, 1($sp) # sa/e $&a % stac

s $s3,12($sp) # sa/e $s3 % stac

s $s2, !($sp) # sa/e $s2 % stac

s $s1, 4($sp) # sa/e $s1 % stac

s $s0, 0($sp) # sa/e $s0 % stac

. # p&%cedu&e b%d9

.

eit1 $s0, 0($sp) # &est%&e $s0 f&%m stac $s1, 4($sp) # &est%&e $s1 f&%m stac

$s2, !($sp) # &est%&e $s2 f&%m stac

$s3,12($sp) # &est%&e $s3 f&%m stac

$&a,1($sp) # &est%&e $&a f&%m stac

addi $sp,$sp, 20 # &est%&e stac p%ite&

j& $&a # &etu& t% caig &%utie

The u"" Proce%ure

ffect of Compi"er Optimi;ation


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Chapter 2 — Instructions: Language of the Computer — &2

ffect of Compi"er Optimi;ation

Compiled with gcc for Pentium 4 under Linu

ffect of Language an% A"gorithm


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ffect of Language an% A"gorithm

Lessons Learnt


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Lessons Learnt

Instruction count and 3'I are not $oodperformance indicators in isolation

3ompiler optimi(ations are sensitive to theal$orithm

Cava/CIT compiled code is si$nificantlyfaster than C\M interpreted 3ompara%le to optimi(ed 3 in some cases

7othin$ can fi# a dum% al$orithm

Arra(s ,s Pointers§2!?


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Arra(s ,s- Pointers

,rray inde#in$ involves Multiplyin$ inde# %y element si(e ,ddin$ to array %ase address

'ointers correspond directly to memoryaddresses 3an avoid inde#in$ comple#ity

?,rraysv

ersus'ointers


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A$M = MIPS Simi"arities§2!


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Chapter 2 — Instructions: Language of the Computer — &'

A$M = MIPS Simi"arities

,0M4 the most popular em%edded core Similar %asic set of instructions to MI'S

0ealStu

ff4,0M

Instruc

tions

,0M MI'S

Date announced !


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Chapter 2 — Instructions: Language of the Computer — &)

Compare an% 0ranch in A$M

"ses condition codes for result of anarithmetic/lo$ical instruction 7e$ative- (ero- carry- overflow 3ompare instructions to set condition codes

without &eepin$ the result Each instruction can %e conditional

Top ? %its of instruction word4 condition value

3an avoid %ranches over sin$le instructions


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The Inte" !'# ISA§2!=


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Chapter 2 — Instructions: Language of the Computer — '*

The Inte" !'# ISA

Evolution with %ac&ward compati%ility @8@8 )!


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Chapter 2 — Instructions: Language of the Computer — '2

The Inte" !'# ISA

Vurther evolution i?@ )!


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The Inte" !'# ISA

,nd further ,MD? )2885*4 e#tended architecture to ? %its EM?T F E#tended Memory ? Technolo$y )288?*

,MD? adopted %y Intel )with refinements* ,dded SSE5 instructions

Intel 3ore )288* ,dded SSE? instructions- virtual machine support

,MD? )announced 288=*4 SSE instructions Intel declined to follow- instead

,dvanced \ector E#tension )announced 288@*

+on$er SSE re$isters- more instructions If Intel didnJt e#tend with compati%ility- its

competitors would Technical ele$ance U mar&et success

0asic !'# $egisters


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0asic !'# $egisters

0asic !'# A%%ressing Mo%es


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0asic !'# A%%ressing Mo%es

Two operands per instructionSource/dest operand Second source operand

0e$ister 0e$ister

0e$ister Immediate

0e$ister Memory

Memory 0e$ister Memory Immediate

Memory addressin$ modes ,ddress in re$ister

,ddress G 0%ase displacement

,ddress G 0%ase 2scale 6 0inde# )scale G 8- !- 2- or 5*

,ddress G 0%ase 2scale 6 0inde# displacement


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Imp"ementing IA132


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Chapter 2 — Instructions: Language of the Computer — '&

Imp"ementing IA 32

3omple# instruction set ma&es

implementation difficult Hardware translates instructions to simpler

microoperations

Simple instructions4 !F! 3omple# instructions4 !Fmany

Microen$ine similar to 0IS3

Mar&et share ma&es this economically via%le 3ompara%le performance to 0IS3

3ompilers avoid comple# instructions

A$M ,' Instructions§2!@


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A$M ,' Instructions

In movin$ to ?1%it- ,0M did a complete

overhaul ,0M v@ resem%les MI'S

3han$es from v=4 7o conditional e#ecution field Immediate field is !21%it constant Dropped load/store multiple '3 is no lon$er a '0

'0 set e#panded to 52 ,ddressin$ modes wor& for all word si(es Divide instruction Branch if e.ual/%ranch if not e.ual instructions

Chapter 2 — Instructions: Language of the Computer — ''

0ealStuff4,0M

v@)?

1%it*Instructio

ns

a""acies§2!<V


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Chapter 2 — Instructions: Language of the Computer — ')

a""acies

'owerful instruction ⇒ hi$her performance Vewer instructions re.uired But comple# instructions are hard to implement

May slow down all instructions- includin$ simple ones

3ompilers are $ood at ma&in$ fast code from simple

instructions

"se assem%ly code for hi$h performance But modern compilers are %etter at dealin$ with

modern processors More lines of code ⇒ more errors and less

productivity

Vallacies

and'itfalls

a""acies


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Chapter 2 — Instructions: Language of the Computer — )+

a ac es

Bac&ward compati%ility ⇒ instruction set

doesnJt chan$e But they do accrete more instructions

#@ instruction set

Pitfa""s


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Chapter 2 — Instructions: Language of the Computer — )*

Se.uential words are not at se.uential

addresses Increment %y ?- not %y !

eepin$ a pointer to an automatic varia%le

after procedure returns e$- passin$ pointer %ac& via an ar$ument 'ointer %ecomes invalid when stac& popped

Conc"u%ing $emars§2283


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Chapter 2 — Instructions: Language of the Computer — )2

g

Desi$n principles! Simplicity favors re$ularity

2 Smaller is faster

5 Ma&e the common case fast

? ood desi$n demands $ood compromises +ayers of software/hardware

3ompiler- assem%ler- hardware

MI'S4 typical of 0IS3 IS,s cf #@

3oncludin$0em

ar&s


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Chapter 02 Computer Organization and Design, Fifth Edition: The Hardware/Software Interface (The...

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Transcript of Chapter 02 Computer Organization and Design, Fifth Edition: The Hardware/Software Interface (The...