CS 61C: Great Ideas in Computer Architecture Control and Pipelining, Part II. Anything can be represented as a number, i.e., data or instrucwons

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1 CS 61C: Ga a i Compu Achicu Cool a Pipliig, Pa 10/29/12 uco: K Aaovic, Ray H. Kaz hdp://i.c.bkly.u/~c61c/fa12 Fall Lcu #28 1 Paalll Rqu Aig o compu.g., Sach Kaz Paalll Tha Aig o co.g., Lookup, A So2wa Paalll ucwo >1 o Wm.g., 5 pipli iucwo Paalll Daa >1 aa o Wm.g., A of 4 pai of wo Hawa cipwo All o Wm Pogammig Laguag You A H! Ha Paalllim & Achiv High Pfomac Hawa Toay Lcu Wahou Scal Compu Co Mmoy pu/upu ucwo Ui() Mai Mmoy Co Sma Pho Logic Ga 2 Compu (Cach) Co FucWoal Ui() A 0 +B 0 A 1 +B 1 A 2 +B 2 A 3 +B 3 Lvl of RpaWo/ pawo High Lvl Laguag Pogam (.g., C) Compil Ambly Laguag Pogam (.g., MPS) Machi pa4o Ambl Machi Laguag Pogam (MPS) Hawa Achicu DcipCo (.g., block iagam) Achicu mplma4o mp = v[k]; v[k] = v[k+1]; v[k+1] = mp; lw $0, 0($2) lw $1, 4($2) w $1, 0($2) w $0, 4($2) Ayhig ca b p a a umb, i.., aa o iucwo ! Logic Cicui DcipCo 10/29/12 (Cicui SchmaCc Diagam) Fall Lcu #28 3 Aga Sucual a Daa Haza Amiiivia Cool Haza 4 Aga Sucual a Daa Haza Amiiivia Cool Haza Haza SiuaWo ha pv awg h x logical iucwo i h x clock cycl 1. Sucual haza Rqui ouc i buy (.g., ah i uyig) 2. Daa haza N o wai fo pviou iucwo o compl i aa a/wi (.g., pai of ock i iff loa) 3. Cool haza Dciig o cool acwo p o pviou iucwo (.g., how much g ba o how cla pio loa u ou) 10/29/12 5 Fall Lcu #28 6 1

2 1. Sucual Haza Coflic fo u of a ouc MPS pipli wih a igl mmoy Loa/So qui mmoy acc fo aa ucwo fch woul hav o all fo ha cycl Cau a pipli bubbl Hc, pipli aapah qui paa iucwo/aa mmoi aliy, povi paa L1 iucwo cach a L1 aa cach Sucual Haza #1: Sigl Mmoy Loa Ra am mmoy wic i am clock cycl Sucual Haza #2: Rgi (1/2) w Ca w a a wi o gi imulaouly? 9 1. Sucual Haza #2: Rgi (2/2) Two iff oluwo hav b u: 1) RgFil acc i VERY fa: ak l ha half h Wm of ag Wi o Rgi uig fi half of ach clock cycl Ra fom Rgi uig co half of ach clock cycl 2) Buil RgFil wih ip a a wi po Rul: ca pfom Ra a Wi uig am clock cycl Daa Haza A iucwo p o complwo of aa acc by a pviou iucwo a $0, $0, $1 ub $2, $0, $3 Fowaig (aka Bypaig) U ul wh i i compu Do wai fo i o b o i a gi Rqui xa cocwo i h aapah

3 Coc Daapah fo Fowaig? Fowaig Pah 13 Chap 4 Th Poco 14 Loa- U Daa Haza Ca alway avoi all by fowaig f valu o compu wh Ca fowa backwa i Wm! Sall/Bubbl i h Pipli Sall i h 15 Chap 4 Th Poco 16 Pipliig a SA Dig MPS ucwo S ig fo pipliig All iucwo a 32- bi Eai o fch a co i o cycl x86: 1- o 17- by iucwo (x86 HW acually ala o ial RSC iucwo!) Fw a gula iucwo foma, 2 ouc gi fil alway i am plac Ca co a a gi i o p Mmoy opa oly i Loa a So Ca calcula a 3 ag, acc mmoy 4 h ag Aligm of mmoy opa Mmoy acc ak oly o cycl Why h DWaWo Rgi Alway i h Sam Fil i MPS SA? op ham fuc 31 6 bi 26 5 bi 21 5 bi 16 5 bi 5 bi 6 bi 0 op immia 6 bi 5 bi 5 bi 16 bi N o hav 2 pa immia if 2 ouc a 1 WaWo alway i am plac SPUR poco (A pojc Dav a Ray Kaz wok o ogh)

4 Aga Sucual a Daa Haza Amiiivia Cool Haza Amiiivia Pojc #4, Lab #10 a #11, (La) HW #6 po Pojc u 11/11 (Suay a x) Pojc i o ifficul, bu i log: o wai fo h wk wh i i u! Sa aly! Look a Logiim lab bfo you a o Pojc #4 Lo of uful Wp a ick fo uig Logiim i ho lab TA Sug Roa will hol x offic hou o h pojc hi comig wk Amiiivia RwighWg of Pojc SWll 40% of ga ovall Pojc 1: 5% Pojc 2: 12.5% Pojc 3: 10% Pojc 4: 12.5% pwoal Exa Ci Pojc 5: up o 5% xa Gol, Silv, a Boz mal o h h fa pojc Co iz a ahwc alo a ciia fo cogiwo Wiig pojc a lc by h TA will b highligh i cla Aga Sucual a Daa Haza Amiiivia Cool Haza Cool Haza Bach mi flow of cool Fchig x iucwo p o bach oucom Pipli ca alway fch coc iucwo SWll wokig o D ag of bach BEQ, BNE i MPS pipli Simpl oluwo pwo 1: Sall o vy bach uwl hav w PC valu Woul a 2 bubbl/clock cycl fo vy Bach! (~ 20% of iucwo xcu) 23. bq Sall => 2 Bubbl/Clock Wh o w o h compa fo h bach? 24 4

5 3. Cool Haza: Bachig Coc Daapah fo BEQ/BNE? pwmizawo #1: pcial bach compaao i Sag 2 A oo a iucwo i co (pco iwfi i a a bach), immialy mak a ciio a h w valu of h PC Bfi: ic bach i compl i Sag 2, oly o ucay iucwo i fch, o oly o o- op i Si No: ma ha bach a il i Sag 3, 4 a 5 10/29/12 25 Fall Lcu # bq Clock Cycl Sall 3. Cool Haza pwo 2: Pic oucom of a bach, fix up if gu wog Mu cacl all iucwo i pipli ha p o gu ha wa wog Simpl hawa if w pic ha all bach a NT ak Why? Bach compaao mov o Dco ag Cool Haza: Bachig pwo #3: Rfi bach l fiiwo: if w ak h bach, o of h iucwo a h bach g xcu by acci Nw fiiwo: whh o o w ak h bach, h igl iucwo immialy followig h bach g xcu (h bach- lay lo) Dlay Bach ma w alway xcu i a2 bach Thi opwmizawo i u wih MPS 3. Cool Haza: Bachig No o Bach- Dlay Slo Wo- Ca Scaio: pu a o- op i h bach- lay lo BD Ca: plac om iucwo pcig h bach i h bach- lay lo a log a h chag o affc h logic of pogam R- oig iucwo i commo way o p up pogam Compil uually fi uch a iucwo 50% of Wm Jump alo hav a lay lo

6 Exampl: Nolay v. Dlay Bach Nolay Bach Dlay Bach o $8, $9, $10 a $1, $2,$3 Dlay Bach/Jump a MPS SA? Why o JAL pu PC+8 i gi 31? a $1, $2, $3 ub $4, $5, $6 bq $1, $4, Exi xo $10, $1, $11 ub $4, $5, $6 bq $1, $4, Exi o $8, $9, $10 xo $10, $1, $11 Exi: Exi: Dlay Bach/Jump a MPS SA? Why o JAL pu PC+8 i gi 31? JAL xcu followig iucjo (PC+4) o houl u o PC+8 Co Schulig o Avoi Sall Ro co o avoi u of loa ul i h x iucwo C co fo A = B + E; C = B + F; all all lw $1, 0($0) lw $2, 4($0) a $3, $1, $2 w $3, 12($0) lw $4, 8($0) a $5, $1, $4 w $5, 16($0) 13 cycl lw $1, 0($0) lw $2, 4($0) lw $4, 8($0) a $3, $1, $2 w $3, 12($0) a $5, $1, $4 w $5, 16($0) 11 cycl P ucwo P ucwo Aw. Thak o pipliig, hav uc h im i ook m o wah my o hi.. Log pipli a alway a wi (ic l wok p ag & a fa clock). A)(oag) i Tu a i Tu B)(g) i Fal a i Tu C)(pik) i Tu a i Fal 35 1) Thoughpu b, o lacy! 2) log pipli o uually ma fa clock a, bu haza ca cau poblm! F A L S E F A L S E 1) Thak o pipliig, hav uc h im i ook m o wah my o hi. 2) Log pipli a alway a wi (ic l wok p ag & a fa clock). 12 a) FF b) FT c) TF ) TT 36 6

7 Th BG Picu A i Cocluio, Pipliig impov pfomac by icaig iucwo houghpu: xploi LP Excu mulwpl iucwo i paalll Each iucwo ha h am lacy Subjc o haza Sucu, aa, cool Sall uc pfomac Bu a qui o g coc ul Compil ca aag co o avoi haza a all Rqui kowlg of h pipli ucu 37 7