rfscv

Return from System Call Vectored

rfscv

Returns from a vectored system call.

Encoding

Binary Layout

19

0:5

/

6:10

/

11:15

/

16:20

82

21:30

/

31

 

Format XL-form

Opcode 0x4C0000A4

Extension Privileged

Operands

Registers Altered

SRR0, SRR1, MSR

Related

More in Privileged

Reference

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

Description

Return from a vectored system call by restoring the processor state from SRR0 and SRR1. This privileged instruction restores PC from SRR0 and MSR from SRR1, typically returning to user mode if MSR[PR] was set in the saved state. It is the inverse of scv.

Operation

PC ← SRR0
MSR ← SRR1

Programming Note

The rfscv instruction is used to return from a system call vectored, restoring the program's execution context by setting the CIA to the value in SRR0 and the MSR from SRR1. Ensure that this instruction is executed at the appropriate privilege level and be aware of any potential exceptions or performance implications related to restoring the machine state.