Texas Instruments TMS320C67X/C67X+ DSP Delay Slots Example, Cycle Program Counter Value Action

BBranch Using a Displacement

Pipeline

Target Instruction

Pipeline

E1

PS

PW

PR

DP

DC

E1

Stage

Read

Written

Branch

n

Taken

Unit in use

.S

Instruction Type

Branch

Delay Slots

5

Example

Table 3−13 gives the program counter values and actions for the following

code example.

0000

0000

B

.S1

LOOP

0000

0004

ADD

.L1

A1, A2, A3

0000

0008

ADD

.L2

B1, B2, B3

0000

000C

LOOP:

MPY

.M1X A3, B3, A4

0000

0010

SUB

.D1

A5, A6, A6

0000

0014

MPY

.M1

A3, A6, A5

0000

0018

MPY

.M1

A6, A7, A8

0000

001C

SHR

.S1

A4, 15, A4

0000

0020

ADD

.D1

A4, A6, A4

Table 3−13. Program Counter Values for Example Branch Using a Displacement

Cycle

Program Counter Value

Action

Cycle 0

0000

0000h

Branch command executes

(target code fetched)

Cycle 1

0000

0004h

Cycle 2

0000

000Ch

Cycle 3

0000

0014h

Cycle 4

0000

0018h

Cycle 5

0000

001Ch

Cycle 6

0000

000Ch

Branch target code executes

Cycle 7

0000

0014h

3-70 Instruction Set SPRU733