dcbi

Data Cache Block Invalidate

dcbi RA, RB

Invalidates a cache block (Privileged).

Encoding

Binary Layout

31

0:5

/

6:10

RA

11:15

RB

16:20

470

21:30

/

31

 

Format X-form

Opcode 0x7C0003AC

Extension Privileged

Operands

• RA
  Base
• RB
  Index

Example

dcbi r4, r5

Related

More in Privileged

Reference

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

Description

Invalidates the data cache block at effective address (RA + RB), removing it from the cache. This is a privileged instruction used for cache management. The instruction does not modify condition registers and may trigger cache coherency operations on multiprocessor systems.

Operation

EA ← (RA) + (RB)
Invalidate cache block at EA

Programming Note

Privileged. Invalidates a cache block without writeback. Use only when you know the block is clean or its contents can be discarded.