Functional Unit Constraints
Pipeline
4-44
SPRU733
Table 4
−
28 shows the instruction constraints for
MPYDP
instructions
executing on the .M unit.
Table 4
−
28. MPYDP .M-Unit Instruction Constraints
Instruction Execution
Cycle
1
2
3
4
5
6
7
8
9
10
11
MPYDP
R
R
R
R
W
W
Instruction Type
Subsequent Same-Unit Instruction Executable
16
×
16 multiply
Xr
Xr
Xr
Xw
Xw
4-cycle
Xr
Xr
Xr
Xu
Xw
Xw
MPYI
Xr
Xr
Xr
Xu
Xu
Xu
MPYID
Xr
Xr
Xr
Xu
Xu
Xu
MPYDP
Xr
Xr
Xr
MPYSPDP
Xr
Xr
Xr
Xw
Xu
Xu
MPYSP2DP
Xr
Xr
Xr
Xw
Xw
Xw
Instruction Type
Same Side, Different Unit, Both Using Cross Path Executable
Single-cycle
Xr
Xr
Xr
Load
Store
DP compare
Xr
Xr
Xr
2-cycle DP
Xr
Xr
Xr
Branch
Xr
Xr
Xr
4-cycle
Xr
Xr
Xr
INTDP
Xr
Xr
Xr
ADDDP/SUBDP
Xr
Xr
Xr
Legend:
= E1 phase of the single-cycle instruction; R = Sources read for the instruction; W = Destinations written for the
instruction;
= Next instruction can enter E1 during cycle; Xr = Next instruction cannot enter E1 during cycle
−
read/
decode constraint; Xw = Next instruction cannot enter E1 during cycle
−
write constraint; Xu = Next instruction cannot
enter E1 during cycle
−
other resource conflict