Functional Unit Constraints

Table 4−21 shows the instruction constraints for ADDSP/SUBSP instructions executing on the .S unit.

Table 4−21. ADDSP/SUBSP .S-Unit Instruction Constraints

 

 

 

 

Instruction Execution

Cycle

1

2

3

4

ADDSP/SUBSP

R

 

 

W

 

 

 

Instruction Type

 

Subsequent Same-Unit Instruction Executable

 

 

 

 

 

Single-cycle

 

n

n

Xw

2-cycle DP

 

n

Xw

Xw

DP compare

 

n

Xw

n

 

ADDDP/SUBDP

 

n

n

n

ADDSP/SUBSP

 

n

n

n

Branch

 

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; Xw = Next instruction cannot enter E1 during cycle−write constraint

SPRU733

Pipeline

4-37

Page 369
Image 369
Texas Instruments TMS320C67X/C67X+ DSP manual 21. ADDSP/SUBSP .S-Unit Instruction Constraints