Instruction Execution Timing
MPC885 PowerQUICC Family Reference Manual, Rev. 2
9-4
Freescale Semiconductor
xor
r4,r3,r5
ori
r7,r8,1
Figure 9-6. Full Completion Queue Timing
9.1.6
Branch Instruction Handling
In
Figure 9-7
the lwz instruction accesses internal memory with one wait state. The IQ and parallel
operation of the BPU allows the two bubbles caused by the bl issue and execution to overlap the two
bubbles caused by the load. Issuing bl causes a bubble because it does no work.
lwz r12,64
(SP)
sub
r3,r12,3
addic
r4,r14,1
bl
func
...
func:
mulli
r5,r3,3
addi
r4,3(r0)
Figure 9-7. Branch Folding Timing
xor
xor
lwz
lwz
sub
and
xor
addic
ori
sub
and
addic
xor
lwz
sub
lwz
lwz
lwz
lwz
lwz
sub
lwz
addic
addic
and
and
Bubble
GCLK1
E Data
Fetch
Decode
Read + Execute
Writeback
L Address Drive
L Data
Cache Address
Load Writeback
E Address
Bubble
addic
lwz
lwz
sub
bl
Bubble
addic
mulli
sub
sub
Bubble
mulli
lwz
Bubble
lwz
lwz
bl
lwz
bl
sub
addic
addic
mulli
Fetch
Decode
Read + Execute
Writeback
L Address Drive
L Data
Load Writeback
Branch Decode
Branch Execute
addi
GCLK1
Summary of Contents for PowerQUICC MPC870
Page 98: ...MPC885 PowerQUICC Family Reference Manual Rev 2 I 4 Freescale Semiconductor ...
Page 118: ...MPC885 Overview MPC885 PowerQUICC Family Reference Manual Rev 2 1 20 Freescale Semiconductor ...
Page 158: ...The MPC8xx Core MPC885 PowerQUICC Family Reference Manual Rev 2 3 18 Freescale Semiconductor ...
Page 288: ...MPC885 PowerQUICC Family Reference Manual Rev 2 III 4 Freescale Semiconductor ...
Page 554: ...MPC885 PowerQUICC Family Reference Manual Rev 2 V 6 Freescale Semiconductor ...
Page 1090: ...UTOPIA Interface MPC885 PowerQUICC Family Reference Manual Rev 2 43 8 Freescale Semiconductor ...
Page 1312: ...Byte Ordering MPC885 PowerQUICC Family Reference Manual Rev 2 A 8 Freescale Semiconductor ...
Page 1336: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 16 Freescale Semiconductor ...
Page 1358: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 38 Freescale Semiconductor ...
Page 1370: ...MPC880 MPC885 PowerQUICC Family Reference Manual Rev 2 E 4 Freescale Semiconductor ...
Page 1386: ...Revision History MPC885 PowerQUICC Family Reference Manual Rev 2 I 2 Freescale Semiconductor ...