Pipelining: Hazards

• A control hazard occurs when a branch instruction is decoded

  • “Flush” the pipeline
  • or: Delayed branch (expose pipeline)

• A data hazard occurs because an operand cannot be read yet

  • Intended by programmer
  • or: Interlock hardware inserts “bubble”

LAC #064h

SAMM AR2

NOP

LACC *-

LAR AR2, DATA

LACC *-

D

E

F

br

G

-

-

X

Y

Y

Z

F

D

R

E

Execute

Read

Decode

Fetch

CD

E

F

br

-

-

-

X

-

Y

Z

BCD

E

F

br

-

-

-

X

-

Y

Z

ABCD

E

F

br

-

-

-

X

-

Y

Z

TMS320C5x example

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