Texas Instruments TMS320C67X/C67X+ DSP User Manual
Page 370
Functional Unit Constraints
Pipeline
4-38
SPRU733
Table 4−22 shows the instruction constraints for ADDDP/SUBDP instructions
executing on the .S unit.
Table 4−22. ADDDP/SUBDP .S-Unit Instruction Constraints
Instruction Execution
Cycle
1
2
3
4
5
6
7
ADDDP/SUBDP
R
R
W
W
Instruction Type
Subsequent Same-Unit Instruction Executable
Single-cycle
Xr
n
n
n
Xw
Xw
2-cycle DP
Xr
n
n
Xw
Xw
Xw
DP compare
Xr
n
n
Xw
Xw
n
ADDDP/SUBDP
Xr
n
n
n
n
n
ADDSP/SUBSP
Xr
Xw
Xw
n
n
n
Branch
Xr
n
n
n
n
n
Instruction Type
Same Side, Different Unit, Both Using Cross Path Executable
Single-cycle
Xr
n
n
n
n
n
DP compare
Xr
n
n
n
n
n
2-cycle DP
Xr
n
n
n
n
n
4-cycle
Xr
n
n
n
n
n
Load
n
n
n
n
n
n
Store
n
n
n
n
n
n
Branch
Xr
n
n
n
n
n
16 × 16 multiply
Xr
n
n
n
n
n
MPYI
Xr
n
n
n
n
n
MPYID
Xr
n
n
n
n
n
MPYDP
Xr
n
n
n
n
n
Legend:
= E1 phase of the single-cycle instruction; R = Sources read for the instruction; W = Destinations written for the
instruction;
n
= 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