dcba

Data Cache Block Allocate

dcba RA, RB

Allocates a cache block without loading from memory (optimization for overwrite).

Details

Allocates a cache block at the effective address (RA + RB) into the data cache without loading data from memory. This instruction is used as an optimization hint when the application will overwrite the entire cache block, avoiding unnecessary memory traffic. No condition registers or status fields are modified.

Pseudocode Operation

EA ← (RA) + (RB)
Allocate cache block at EA without loading from memory

Example

dcba r4, r5

Encoding

Binary Layout
31
0
/
6
RA
11
RB
16
758
21
/
31
 
Format X-form
Opcode 0x7C0005EC
Extension Base

Operands

  • RA
    Base
  • RB
    Index