dststt

Data Stream Touch for Store Transient

dststt RA, RB, STRM

Initiates a transient prefetch for writing.

Details

Initiates a hardware prefetch stream for transient (non-temporal) data that is likely to be written in the near future and not reused. The instruction computes an effective address from RA and RB and hints to the memory subsystem to prepare the cache line for write operations with transient semantics. This advisory instruction supports transient store-stream prefetching to reduce cache pollution.

Pseudocode Operation

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

Example

dststt r4, r5, 0

Encoding

Binary Layout
31
0
STRM
6
RA
11
RB
16
374
21
/
31
 
Format X-form
Opcode 0x7C0002EC
Extension Base

Operands

  • RA
    Base
  • RB
    Index
  • STRM
    Stream ID