BG3 Datapath Control

8/13/2019 BG3 Datapath Control

1/28

Hc k 2 2010-2011 T chc my tnh

T chc my tnhHc k 2 2010-2011

Bi 3: Datapath v Control(c ch4: 4.1 4.5)

H Vit VitThS. GVC

B mn K thut my tnh, Khoa in t Vin thng

i hc Bch khoa Nng

[email protected]


2/28


Mc tiu Bi 3

Thit k phn cng cho mt cu lnh c th i vi mtb x l MIPS single-cycle c tp lnh n gin


3/28


Gian bp ca Von Neumann

Cc thanh ghi

ALU

Control

Memor

y

Outpu

t

Program

Dat

a

Chn mnPC

Bt u

Processo

r

Inpu

t


4/28


S vic bt u t u?

T mt thanh ghi:program counter (PC).PC cha a ch ca lnh k tip cn phi

thc hin.u tin, PC cha a ch ca v tr nh

bt u chng trnh.


5/28


Chng trnh u?

M my ca

chng trnh

B nh

Bt u

Programcounter

(PC)

Processo

r


6/28


Chng trnh c thc hin?Bt u

PC cha a ch bt u chng trnh

Ly t lnh ti v tr nh c a ch PC

v PC PC + 4 chun b cho lnh k tip

Gii m lnh

Xong

chng

trnh

XongChaST

OP

Thc hin lnh

Lu kt qu vo thanh ghi hoc b nh


7/28


Datapath v Control

Datapath: B nh, Cc thanh ghi, Cc b cng, ALU, v ccbus thng tin. Mi bc (Ly lnh, gii m, thc hin, lukt qu) cn truyn d liu gia b nh, cc thanh ghi v

ALU.

Control: Datapath cho mi bc c duy tr bi cc tnhiu iu khin . Cc tn hiu iu khin c to ra t n

v control nhm ch hng truyn d liu trn bus thng tin

v ch nh chc nng cho ALU v b nh


8/28


Datapath cho Ly lnh

PC B nh lnh

4

a ch

T lnh i ti

cc thanh ghi v Control

Add


9/28


File thanh ghi: mt thnh phn ca

Datapath

32 Registers

(reg. file)Write

register

reg 1 data

reg 2 data

5

5

5

3

2

3

2

3

2

reg 1

reg 2

Read

registers

Write

data

RegWrite

n t Control


10/28


ALU c th thc hin nhiu

php ton

ALU

3

zero kt qu

overflow

Cc tn hiu chn php tonn t Control

Chn php tonALU

000AND

001OR

010Add

110Subtract

111Set on less than

zero = 1, khi mi bit ca kt qu bng 0


11/28


Cc lnh kiu R

Cc lnh s hc v logicadd, sub, sltV d: add $t0, $s1, $s2oM my ca lnh

00000010001 10010 01000 00000 100000

Opcode$s1 $s2 $t0 function

oc 2 thanh ghi t File thanh ghi

oGhi kt qu vo 1 thanh ghi

oOpcodev functioni ti Control to ra tn

hiu RegWrite v cc tn hiu chn php ton


12/28


Datapath cho lnh kiu R

32 Registers(reg. file)

Write

reg.

number

5

5

5

3

2

3

2

$s1

$s2

Read

register

numbers

Writedata

ALU

3

zer

o result

overflow

Cc tn hiu chnPhp ton

10001

10010

01000

RegWrite

3

2$t

0

000000 10001 10010 01000 00000 100000

opcode $s1 $s2 $t0 function (add)


13/28


Load v Store

Cc lnh kiu Ilw $t0, 1200 ($t1)10001101001 01000 0000 0100 1011 0000

opcode $t1 $t0 1200

sw $t0, 1200 ($t1)10101101001 01000 0000 0100 1011 0000

opcode$t1 $t0 1200


14/28


Datapath cho lw

Operation

select

from control

(add)

32 Registers

(reg. file)

Write reg.

number

5

5

5

3

2

3

2

$t

1Read

register

numbers

Write data

AL

U

3

zeroresult

overflow

0100

1

0100

0

RegWritefrom control

activated

3

2Sign

exten

d1

6

100 1011

Data

memory

Addr.

Read

data

MemWrite

MemRead

activated

$t

0 Write

data

100011 01001 01000 0000 0100 1011 0000

opcode$t1 $t0 1200

mem. data to $t0


15/28


Datapath cho sw

Operation

select

from control

(add)

32 Registers

(reg. file)

Write reg.

number

5

5

5

3

2

3

2

$t

1

$t

0

Read

register

numbers

Write data

AL

U

3

zeroresult

overflow

0100

1

RegWrite

from control

3

2Sign

exten

d1

6

100 1011

Data

memory

Addr.

Read

data

$t0data to

mem.

0100

0

MemWrite

activated

MemRead

Write

data

101011 01001 01000 0000 0100 1011 0000

opcode$t1 $t0 1200

3

2


16/28


Lnh r nhnh (kiu I)

beq $s1, $s2, 25 # nu $s1 = $s2, PC bqua 25 lnh

16-bits

00010010001 10010 0000 0000 0001 1001

opcode$s1 $s2 25

Lu : C th r nhnh trong phm vi 215lnh t a ch hin

thi trong PC.


17/28


Datapath cho beq

Operation

select

from control (subtract)

32 Registers

(reg. file)

Write reg.

number

5

5

5

3

2

3

2

$s

1Read

register

numbers

Write data

AL

U

3

zeroresult

overflow

1000

1

1001

0

RegWrite

from control

3

2

Sign

exten

d

1

60 0000 0001

1

Shift

left 2

Ad

d

16-bits

00010010001 10010 0000 0000 0001 1001opcode $s1 $s2 25

$s

2

3

2

3

2

3

2

To

branch

cont ro l

log ic

PC+

4From inst ruc t ionfetch datapath

Branc

h

target3

2


18/28


Lnh J (kiu J)

j 2500 # nhy n lnh ti 1000026-bits

0000100000 0000 0000 0010 0111 0001 00opcode2,500

0000 0000 0000 0000 0010 0111 00010000bits 28-31 from PC+4

32-bit jump

address


19/28


Datapath cho J

PCInstruction

MemoryAddressInstruction

word to

control and

registers

4Add

1

mux

0

0

mux1

opcode (bits 26-31)

to control

Shift

left 2

6

2

6

Branc

h

addr.

Branc

h Jum

p

3

2

3

2

3

2

2

8

4

3

2

3

2

PC+

4

3

2


20/28


Instr.

mem.PC

Add

Reg. File

Data

mem.

1 mux 0

1 mux 0

0 mux 1

4

1 mux 0

Sig

n

ext.

Shift

left 2

ALU

Cont.

CONTROLopcode

MemWrit

e

MemReadALU

Branc

h

zero

0-15

0-5

11-15

16-20

21-25

26-31

ALU

0 mux 1

Shift

left2

0-25 Jum

p

RegDs

t

MemtoReg


21/28


Control

Contro

l

Logic

Instruction

bits 26-31

opcode

RegDst

Jump

Branch

MemRead

MemtoReg

ALUOp

MemWrite

ALUSrc

RegWriteALU

Contro

l

Instruction

bits 0-5

funct.

2

to ALU


22/28


Control Logic: Truth Table

Instr

type

Inputs: instr. opcode bits Outputs: control signals

31 30 29 28 27 26Re

gD

st

Ju

mp

AL

US

rc

Me

mt

oR

eg

Re

gW

rite

Me

m

Re

ad

Me

m

Wri

te

Br

an

ch

AL

O

Op

1

AL

UO

p2

R 0 0 0 0 0 0 1 0 0 0 1 0 0 0 1 0

lw 1 0 0 0 1 1 0 0 1 1 1 1 0 0 0 0

sw 1 0 1 0 1 1 X 0 1 X 0 0 1 0 0 0

beq 0 0 0 1 0 0 X 0 0 X 0 0 0 1 0 1

j 0 0 0 0 1 0 X 1 X X 0 X 0 X X X


23/28


Thi gian cho mt lnh?

Gi s control hot ng nhanh th thigian dnh cho mt lnh ch yu l thigian lm vic ca ALU, thi gian c/ghi

b nh v thi gian c/ghi thanh ghi.

Lnh s hc (kiu R) Ly lnh (c b nh) 2ns

c thanh ghi 1ns

Hot ng ca ALU 2ns

Ghi thanh ghi 1ns

Tng cng 6ns


24/28


Thi gian cho lw v sw (Kiu I)

Lnh s hc (kiu R) 6nsLoad word (kiu I)oLy lnh (c b nh) 2ns

oc thanh ghi 1nsoHot ng ALU 2ns

oLy d liu (c b nh ) 2ns

oGhi thanh ghi 1ns

oTng cng 8ns

Store word (khng ghi thanh ghi) 7ns


25/28


Thi gian cho beq (Kiu I)

S hc (R) 6nsLoad word (I) 8ns

Store word (I) 7nsBranch on equal (I)oLy lnh (c b nh) 2ns

oc thanh ghi 1ns

oHot ng ALU 2ns

oTng cng 5ns


26/28


Thi gian cho Jump (Kiu J)

S hc (R) 6nsLoad word (I) 8ns

Store word (I) 7nsBranch on equal (I) 5nsJump (J):oLy lnh (c b nh) 2ns

oTng cng 2ns


27/28


Chu k ng h phi bng ?

Nu mi lnh phi c thc hin trongmt chu k ng h th:oChu k ng h t nht phi bng 8ns c th

hon tt lnh lu nht l lnh lw.

oy gi l b x l Single-Cycle.

oCc lnh khc cng tn chng y thi gian.

Phng php tng tc: B x l Multicyclev Pipelining.


28/28


Tm tt

c th thit k datapath v control cnphi bit khun dng (kiu) ca cc culnh: R, I, J

Tt c cc lnh ca mt b x l Single-Cycle u c thc hin trong mt chu k

ng h (mc d thi gian cn thit c th

b hn)

BG3 Datapath Control

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