mpc823rg Freescale Semiconductor, Inc, mpc823rg Datasheet - Page 183

• Manufacturer Part Number: mpc823rg
• Description: Mpc823 Powerquicc Integrated Communications Processor For Portable Systems
• Manufacturer: Freescale Semiconductor, Inc

8.2.2 Writeback
8.2.2.1 WRITEBACK ARBITRATION
mulli r12,r4,3
sub
addic r4,r12,1
The addic instruction is dependent on the mulli result. Since the single-cycle instruction
sub has priority on the writeback bus over the mulli and the mulli writeback is delayed one
clock and causes a bubble in the execute stream.
mulli r12,r4,3
sub
addic r4,r3,1
GCLK1
FETCH
DECODE
READ + EXECUTE
WRITEBACK
FETCH
DECODE
READ + EXECUTE
WRITEBACK
GCLK1
r3,r15,3
r3,r15,3
Figure 8-3. Another Example of a Writeback Arbitration
Figure 8-2. Example of a Writeback Arbitration
MULLI
MULLI
Freescale Semiconductor, Inc.
For More Information On This Product,
MULLI
MULLI
SUB
SUB
MPC823 REFERENCE MANUAL
MULLI
MULLI
Go to: www.freescale.com
SUB
SUB
ADDIC
ADDIC
SUB, MULLI
SUB, MULLI
ADDIC
ADDIC
SUB
SUB
BUBBLE
ADDIC
MULLI
ADD
ADDIC
Instruction Execution Timing
MULLI
ADD
8-5