msgsnd

Message Send

msgsnd RB

Sends a doorbell interrupt to another processor.

Encoding

Binary Layout

31

0:5

/

6:10

/

11:15

RB

16:20

206

21:30

/

31

 

Format X-form

Opcode 0x7C00019C

Extension Privileged

Operands

• RB
  Message Type

Example

msgsnd r5

Related

More in Privileged

Reference

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

Description

The instruction sends a message to other threads based on the contents of register RB. The message type and destination thread(s) are specified in RB.

Operation

msgtype ← GPR(RB)32:36
payload ← GPR(RB)37:63
if (msgtype = 0x05)
then
    send_msg(msgtype, payload)

Programming Note

If msgsnd is used to notify the receiver that updates have been made to storage, a sync should be placed between the stores and the msgsnd. See Section 6.9.2.