Functional Unit Constraints

Table 4−23 shows the instruction constraints for branch instructions executing on the .S unit.

Table 4−23. Branch .S-Unit Instruction Constraints

 

 

 

 

Instruction Execution

Cycle

1

2

3

4

5

6

7

8

Branch

R

 

 

 

 

 

 

 

Instruction Type

 

Subsequent Same-Unit Instruction Executable

 

 

 

 

 

 

 

 

 

Single-cycle

 

n

n

n

n

n

n

n

DP compare

 

n

n

n

n

n

n

n

2-cycle DP

 

n

n

n

n

n

n

n

 

ADDDP/SUBDP

 

n

n

n

n

n

n

n

ADDSP/SUBSP

 

n

n

n

n

n

n

n

Branch

 

n

n

n

n

n

n

n

 

 

 

Instruction Type

Same Side, Different Unit, Both Using Cross Path Executable

 

 

 

 

 

 

 

 

 

Single-cycle

 

n

n

n

n

n

n

n

Load

 

n

n

n

n

n

n

n

Store

 

n

n

n

n

n

n

n

INTDP

 

n

n

n

n

n

n

n

ADDDP/SUBDP

 

n

n

n

n

n

n

n

16 16 multiply

 

n

n

n

n

n

n

n

4-cycle

 

n

n

n

n

n

n

n

MPYI

 

n

n

n

n

n

n

n

MPYID

 

n

n

n

n

n

n

n

MPYDP

 

n

n

n

n

n

n

n

 

 

 

 

 

 

 

 

 

Legend: = E1 phase of the single-cycle instruction; R = Sources read for the instruction; n = Next instruction can enter E1 during cycle

The branch on register instruction is the only branch instruction that reads a general-purpose register

SPRU733

Pipeline

4-39

Page 371
Image 371
Texas Instruments TMS320C67X/C67X+ DSP manual 23. Branch .S-Unit Instruction Constraints