Texas Instruments TMS320C67X/C67X+ DSP User Manual

Page 367

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Functional Unit Constraints

4-35

Pipeline

SPRU733

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

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