CSR Bit Fields

RISC-V pmpaddr29 CSR Register

Address 0x3CDPrivilege MachineAccess RW / XLENMachine physical memory protection CSRs

pmpaddr29 is a PMP address CSR holding address-matching information for a physical memory protection entry.

Field Map

Understand pmpaddr29 By Bit Fields

1 key fields
XLEN-1:0

ADDR

RW

PMP address encoding; interpretation depends on the A field in the corresponding pmpcfg entry.

ADDR (bits XLEN-1:0) — PMP address encoding; interpretation depends on the A field in the corresponding pmpcfg entry.

What This Field Controls

  • - PMP address encoding; interpretation depends on the A field in the corresponding pmpcfg entry.

Common Values

This field is better understood together with surrounding context than as a fixed memorized enumeration.

Open Official Manual

What To Check First When Reading This CSR

  • - First confirm that the current hart implements pmpaddr29; unimplemented or insufficiently privileged accesses raise an illegal-instruction exception.
  • - Use address 0x3CD and the lowest access privilege (Machine) to decide whether software may read it directly.
  • - Do not assume fixed values for reserved, WARL, or WLRL bits; interpret the value according to the specification and implementation.

Risk Checks Before Writing

  • - Preserve bits that are not being changed so reserved or implementation-defined fields are not written with invalid values.
  • - Prefer CSRRS/CSRRC for local set/clear operations to avoid CSRRW overwriting concurrently updated status bits.

Put It Back Into A Real Flow

1

During initialization or the relevant privileged flow, software reads pmpaddr29 to observe the current state.

2

Modify only the target fields while preserving all other bits.

3

Read back the CSR or validate through later trap, interrupt, or context-switch behavior that the setting took effect.