Functional Unit Hazards
6-31
TMS320C67x Pipeline
Table 6–13 shows the instruction hazards for 4-cycle instructions executing on
the .L unit.
Table 6–13. 4-Cycle .L-Unit Instruction Hazards
Instruction Execution
Cycle
1
2
3
4
5
4-cycle
R
W
Instruction Type
Subsequent Same-Unit Instruction Executable
Single-cycle
n
n
Xw
n
4-cycle
n
n
n
n
INTDP
n
n
n
n
ADDDP/SUBDP
n
n
n
n
Instruction Type
Same Side, Different Unit, Both Using Cross Path Executable
Single-cycle
n
n
n
n
DP compare
n
n
n
n
2-cycle DP
n
n
n
n
4-cycle
n
n
n
n
Load
n
n
n
n
Store
n
n
n
n
Branch
n
n
n
n
16
16 multiply
n
n
n
n
MPYI
n
n
n
n
MPYID
n
n
n
n
MPYDP
n
n
n
n
Legend:
E1 phase of the single-cyle instruction
R
Sources read for the instruction
W
Destinations written for the instruction
n
Next instruction can enter E1 during cycle
Xw
Next instruction cannot enter E1 during cycle–write hazard