Write must
complete
before the
two reads can
complete
2 reads
performed
Pipeline Conflicts
8-13
Pipeline Operation
Example 8–8. Single Store Followed by Two Reads
STF R
0,*AR1
; R0
→
*AR1
LDF
*AR2,R1
; *AR2
→
R1 in parallel with
LDF
*AR3,R2
; *AR3
→
R2
Pipeline Operation
PC
Fetch
Decode
Read
Execute
n
STF
—
—
—
n+1
LDF
LDF
STF
—
—
n+2
W
LDF
LDF
STF
—
n+3
X
W
LDF
LDF
STF
n+4
X
W
LDF
LDF
(nop)
n+4
Y
X
W
LDF
LDF
Note:
W, X, Y = Instruction representations