dstst

Data Stream Touch for Store

dstst RA, RB, STRM

Initiates a prefetch for writing.

Encoding

Binary Layout

31

0:5

STRM

6:10

RA

11:15

RB

16:20

374

21:30

/

31

 

Format X-form

Opcode 0x7C0002EC

Extension Base

Operands

• RA
  Base
• RB
  Index
• STRM
  Stream ID

Example

dstst r4, r5, 0

Related

More in Base

Reference

View in PowerISA v3.1C Specification ↗ OPF Power ISA v3.1C

Description

Initiates a hardware prefetch stream for data that is likely to be written in the near future. The instruction computes an effective address from RA and RB and hints to the memory subsystem to begin preparing the cache line for write-back operations with the temporal locality specified by STRM. This is an advisory instruction supporting store-stream prefetching.

Operation

EA ← (RA | 0) + RB; InitiateDataStream(EA, STRM, isStore=1, isTransient=0)