dstt

Data Stream Touch Transient

dstt RA, RB, STRM

Initiates a transient (non-temporal) data stream prefetch.

Details

Initiates a hardware prefetch stream for transient (non-temporal) data that is likely to be loaded in the near future and not reused. The instruction computes an effective address from RA and RB and hints to the memory subsystem to begin streaming data with transient semantics specified by STRM. This is an advisory instruction that may reduce cache pollution for one-time accesses.

Pseudocode Operation

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

Example

dstt r4, r5, 0

Encoding

Binary Layout
31
0
STRM
6
RA
11
RB
16
342
21
/
31
 
Format X-form
Opcode 0x7C0002AC
Extension Base

Operands

  • RA
    Base
  • RB
    Index
  • STRM
    Stream ID