Texas Instruments TMS320C67X/C67X+ DSP manual 20 -Cycle DP .S-Unit Instruction Constraints

Functional Unit Constraints

Table 4−20 shows the instruction constraints for 2-cycle DP instructions exe- cuting on the .S unit.

Table 4−20. 2-Cycle DP .S-Unit Instruction Constraints

			Instruction Execution
Cycle	1	2	3
2-cycle	RW	W
Instruction Type		Subsequent Same-Unit Instruction Executable
Single-cycle		Xw	n
DP compare		n	n
2-cycle DP		Xw	n
ADDDP/SUBDP		n
ADDSP/SUBSP		n
Branch		n	n
Instruction Type	Same Side, Different Unit, Both Using Cross Path Executable
Single cycle		n	n
Load		n	n
Store		n	n
INTDP		n	n
ADDDP/SUBDP		n	n
16 ⋅ 16 multiply		n	n
4-cycle		n	n
MPYI		n	n
MPYID		n	n
MPYDP		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; Xw = Next instruction cannot enter E1 during cycle-write constraint

4-36 Pipeline SPRU733