Gestione degli hazard - Dipartimento di Ingegneria Informatica e ...

Program
execution order
(in instructions)‏
sub $2, $1, $3
and $12, $2, $5
Time (in clock cycles)‏
IM Reg
Data Forwarding
CC 1 CC 2 CC 3 CC 4 CC 5 CC 6
IM Reg
DM Reg
Metodologie di progettazione Hardware/Software- LS Ing. Informatica
IM Reg DM Reg
CC 7 CC 8 CC 9
Value of register $2 : 10 10 10 10 10/– 20 – 20 – 20 – 20 – 20
Value of EX/MEM : X X X – 20 X X X X X
Value of MEM/WB : X X X X – 20 X X X X
or $13, $6, $2
add $14, $2, $2
sw $15, 100($2)‏
R e g is t e rs
b . W i th fo rw a rd in g
DM Reg
Metodologie di progettazione Hardware/Software- LS Ing. Informatica
IM Reg
DM Reg
IM Reg
DM Reg
Implementazione del forwarding
ID / E X E X / M E M
M E M /W B
R s
R t
R t
R d
M
u
x
M
u
x
F o rw a r d B
M
u
x
F o r w a r d A
A L U
F o rw a r d in g
u n it
D a ta
m e m o ry
E X /M E M .R e g is te rR d
M E M /W B .R e g is t e rR d
M
u
x
7
8
4