dcread

Data Cache Read

dcread RT, RA, RB

Reads a data cache tag or data (Debug).

Encoding

Binary Layout

31

0:5

RT

6:10

RA

11:15

RB

16:20

486

21:30

/

31

 

Format X-form

Opcode 0x7C0003CC

Extension Embedded

Operands

• RT
  Target
• RA
  Base
• RB
  Index

Example

dcread r3, r4, r5

Related

More in Embedded

Reference

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

Description

Reads and returns a data cache tag or data value from the address RA + RB into register RT. This is an embedded debug/diagnostic instruction used to inspect data cache contents; exact behavior (tag vs. data read, selection mechanism) is implementation-dependent. The instruction requires supervisor privilege and may not be available on all embedded PowerPC implementations.

Operation

addr ← (RA) + (RB)
RT ← Read data cache entry at addr