Functional Unit Constraints

Table 4−19 shows the instruction constraints for DP compare instructions executing on the .S unit.

Table 4−19. DP Compare .S-Unit Instruction Constraints

 

 

 

Instruction Execution

Cycle

1

2

3

DP compare

R

RW

 

 

 

 

Instruction Type

 

Subsequent Same-Unit Instruction Executable

 

 

 

 

Single-cycle

 

Xrw

n

DP compare

 

Xr

n

2-cycle DP

 

Xrw

n

ADDDP/SUBDP

 

Xr

n

ADDSP/SUBSP

 

Xr

n

Branch

 

Xr

n

Instruction Type

Same Side, Different Unit, Both Using Cross Path Executable

 

 

 

 

Single-cycle

 

Xr

n

Load

 

Xr

n

Store

 

Xr

n

INTDP

 

Xr

n

ADDDP/SUBDP

 

Xr

n

 

16 16 multiply

 

Xr

n

4-cycle

 

Xr

n

MPYI

 

Xr

n

MPYID

 

Xr

n

MPYDP

 

Xr

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; Xrw = Next instruction cannot enter E1 during cycle-read/decode/write constraint

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

SPRU733

Pipeline

4-35

Page 367
Image 367
Texas Instruments TMS320C67X/C67X+ DSP manual 19. DP Compare .S-Unit Instruction Constraints