RISC-V mimpid CSR Register

Address 0xF13Privilege MachineAccess RO / XLENMachine implementation and hart identification CSRs

mimpid is a read-only Machine CSR identifying the implementation version of the processor.

Related Search Terms

mimpid CSR mimpid 0xF13 machine implementation ID implementation version RISC-V mimpid read only machine CSR

Bit Overview

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bit 3 = only bit 3; bits 12..11 = bits 12 down to 11

MSBLSB

VALUE63:0RO

Field Map

Understand mimpid By Bit Fields

1 key fields

XLEN-1:0

VALUE

Full register value of mimpid; bits not split out here follow the relevant extension or privileged specification, and reserved or WPRI fields should be preserved when writing other fields and ignored on reads.

VALUE (bits XLEN-1:0) — Full register value of mimpid; bits not split out here follow the relevant extension or privileged specification, and reserved or WPRI fields should be preserved when writing other fields and ignored on reads.

What This Field Controls

- Full register value of mimpid; bits not split out here follow the relevant extension or privileged specification, and reserved or WPRI fields should be preserved when writing other fields and ignored on reads.

Common Values

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

Official Basis & Search Notes

mimpid is a RO CSR in machine implementation and hart identification csrs at 0xF13. Check privilege and implemented extensions before interpreting its bit fields.

mimpid address, lowest access privilege, and access class are checked against the official CSR table: 0xF13, Machine, RO.

Read it as part of machine implementation and hart identification csrs before interpreting the bit-field table on this page.

This is a read-only CSR; do not write it. Ignore reserved or WPRI field values on reads, and preserve unchanged fields when writing writable CSRs.

RISC-V Privileged Architecture Manual RISC-V Unprivileged ISA Manual

What To Check First When Reading This CSR

- First confirm that the current hart implements mimpid; unimplemented or insufficiently privileged accesses raise an illegal-instruction exception.
- Use address 0xF13 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

- mimpid is a read-only CSR; writes raise an illegal-instruction exception or are disallowed by the implementation.

Put It Back Into A Real Flow

Read mimpid to obtain hardware or runtime state.

Interpret the returned value according to the field descriptions and do not attempt to write it back.

If reading fails at the current privilege level, handle the illegal-instruction exception path.

FAQ

Can mimpid be accessed from any privilege level?

Do not decide from the CSR name alone. The official CSR address encoding and tables define the lowest access privilege; this entry records mimpid as Machine. Access with insufficient privilege or to an unimplemented CSR raises an illegal-instruction exception.

What is easiest to miss when using mimpid?

mimpid is read-only. Treat it as an observation point, do not try to write it, and do not depend on fixed values for reserved or WPRI fields.