Texas Instruments TMS320C67X/C67X+ DSP manual 28. Mpydp .M-Unit Instruction Constraints

Functional Unit Constraints

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	n	n	n	Xw	Xw	n	n
4-cycle		Xr	Xr	Xr	Xu	Xw	Xw	n	n	n	n
MPYI		Xr	Xr	Xr	Xu	Xu	Xu	n	n	n	n
MPYID		Xr	Xr	Xr	Xu	Xu	Xu	n	n	n	n
MPYDP		Xr	Xr	Xr	n	n	n	n	n	n	n
MPYSPDP		Xr	Xr	Xr	Xw	Xu	Xu	n	n	n	n
MPYSP2DP		Xr	Xr	Xr	Xw	Xw	Xw	n	n	n	n
Instruction Type	Same Side, Different Unit, Both Using Cross Path Executable
Single-cycle		Xr	Xr	Xr	n	n	n	n	n	n	n
Load		n	n	n	n	n	n	n	n	n	n
Store		n	n	n	n	n	n	n	n	n	n
DP compare		Xr	Xr	Xr	n	n	n	n	n	n	n
2-cycle DP		Xr	Xr	Xr	n	n	n	n	n	n	n
Branch		Xr	Xr	Xr	n	n	n	n	n	n	n
4-cycle		Xr	Xr	Xr	n	n	n	n	n	n	n
INTDP		Xr	Xr	Xr	n	n	n	n	n	n	n
ADDDP/SUBDP		Xr	Xr	Xr	n	n	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; Xu = Next instruction cannot enter E1 during cycle−other resource conflict

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