Branch Timing Examples; Timing Example-Branch Timing For A Btac Hit - IBM PowerPC 604 User Manual

6.4.4.1 Branch Timing Examples
This section shows how the timing of a branch is affected depending upon whether the
branch hits in the BTAC, or whether correction is required in one of the stages. The
following examples use the following code sequence:
and
ld
add
be
or
cmp
ld
mulli
6.4.4.1.1 Timing Example-Branch Timing for a BTAC Hit
Figure 6-9 shows the timing for a branch instruction that had a BTAC hit.
0
•••
0 and
3 be
2
I
I
: 1
I
)
4
or
)1 . . : · · · . · . : · · · . · . : · · · . . · : · · · . I
. . ?
3 4 5 6
. ...·.. . . .. -
~ - ; ·,
i 111
C=:J
Fetch
I
I
I
Decode
~
Dispatch
1111111111
Execute
[IIl(Il]
Complete
- Write-Back
I I
Figure 6-9. Instruction Timing-Branch with BT AC Hit
Chapter 6. Instruction Timing
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