Texas Instruments TMS320C67X/C67X+ DSP User Manual

Page 134

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B IRP

Branch Using an Interrupt Return Pointer

3-74

Instruction Set

SPRU733

Target Instruction

Pipeline
Stage

E1

PS

PW

PR

DP

DC

E1

Read

IRP

Written
Branch
Taken

n

Unit in use

.S2

Instruction Type

Branch

Delay Slots

5

Example

Table 3−15 gives the program counter values and actions for the following
code example. Given that an interrupt occurred at

PC = 0000 1000

IRP = 0000 1000

0000 0020

B

.S2 IRP

0000 0024

ADD

.S1 A0, A2, A1

0000 0028

MPY

.M1 A1, A0, A1

0000 002C

NOP

0000 0030

SHR

.S1 A1, 15, A1

0000 0034

ADD

.L1 A1, A2, A1

0000 0038

ADD

.L2 B1, B2, B3

Table 3−15. Program Counter Values for B IRP Instruction

Cycle

Program Counter Value

Action

Cycle 0

0000 0020

Branch command executes
(target code fetched)

Cycle 1

0000 0024

Cycle 2

0000 0028

Cycle 3

0000 002C

Cycle 4

0000 0030

Cycle 5

0000 0034

Cycle 6

0000 1000

Branch target code executes

Pipeline

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