Functional Unit Constraints

Table 4−35 shows the instruction constraints for ADDDP/SUBDP instructions executing on the .L unit.

Table 4−35. ADDDP/SUBDP .L-Unit Instruction Constraints

 

 

 

 

Instruction Execution

Cycle

1

2

3

4

5

6

7

8

ADDDP/SUBDP

R

R

 

 

 

W

W

 

 

 

 

Instruction Type

 

Subsequent Same-Unit Instruction Executable

 

 

 

 

 

 

 

 

 

Single-cycle

 

Xr

n

n

n

Xw

Xw

n

4-cycle

 

Xr

Xw

Xw

n

n

n

n

INTDP

 

Xrw

Xw

Xw

n

n

n

n

 

ADDDP/SUBDP

 

Xr

n

n

n

n

n

n

 

 

 

Instruction Type

Same Side, Different Unit, Both Using Cross Path Executable

 

 

 

 

 

 

 

 

 

Single-cycle

 

Xr

n

n

n

n

n

n

DP compare

 

Xr

n

n

n

n

n

n

2-cycle DP

 

Xr

n

n

n

n

n

n

 

4-cycle

 

Xr

n

n

n

n

n

n

Load

 

n

n

n

n

n

n

n

Store

 

n

n

n

n

n

n

n

Branch

 

Xr

n

n

n

n

n

n

16 16 multiply

 

Xr

n

n

n

n

n

n

MPYI

 

Xr

n

n

n

n

n

n

MPYID

 

Xr

n

n

n

n

n

n

MPYDP

 

Xr

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

SPRU733

Pipeline

4-51

Page 383
Image 383
Texas Instruments TMS320C67X/C67X+ DSP manual 35. ADDDP/SUBDP .L-Unit Instruction Constraints