Instruction Syntax

Mnemonic	Format	Flags
mfsrr0	rD	None

Instruction Encoding

Field	Bits	Description
Primary Opcode	0-5	011111 (0x1F)
rD	6-10	Destination register
rA	11-15	00000 (unused)
rB	16-20	00000 (unused)
XO	22-29	01010110 (0x56)

Operation

rD ← SRR0

MFSRR0 copies the contents of the Save/Restore Register 0 (SRR0) into the destination register rD.

1. Reads the value from the Save/Restore Register 0 (SRR0)
2. Copies it to the destination register rD

Note: SRR0 contains the address of the instruction that caused the exception.

Affected Registers

General Purpose Registers (GPRs)

• rD (Destination register) - Loaded with SRR0 value

Examples

Basic SRR0 Read

# Read the Save/Restore Register 0
mfsrr0 r3          # r3 = SRR0

Exception Handler

# In an exception handler
exception_handler:
mfsrr0 r3          # Get the exception address
# Process the exception using the address in r3

Debug Information

# Get exception address for debugging
mfsrr0 r10         # Save exception address
# Log or process the address for debugging

Related Instructions

mtsrr0 (Move to SRR0), mfsrr1 (Move from SRR1), mtsrr1 (Move to SRR1), mfdar (Move from DAR)