# Copyright lowRISC contributors (OpenTitan project).
# Copyright zeroRISC Inc.
# Modified by Ruben Niederhagen and Hoang Nguyen Hien Pham - authors of
# "Improving ML-KEM & ML-DSA on OpenTitan - Efficient Multiplication Vector Instructions for OTBN"
# (https://eprint.iacr.org/2025/2028).
# Copyright Ruben Niederhagen and Hoang Nguyen Hien Pham.
# Licensed under the Apache License, Version 2.0, see LICENSE for details.
# SPDX-License-Identifier: Apache-2.0

- name: mod
  address: 0
  doc: |
    The modulus used by the {{#acc-insn-ref BN.ADDM}} and {{#acc-insn-ref BN.SUBM}} instructions.
    This WSR is also visible as CSRs `MOD0` through to `MOD7`.

- name: rnd
  address: 1
  read-only: true
  doc: |
    An AIS31-compliant class PTG.3 random number with guaranteed entropy and forward and backward secrecy.
    Primarily intended to be used for key generation.

    The number is sourced from the EDN via a single-entry cache.
    Reads when the cache is empty will cause ACC to be stalled until a new random number is fetched from the EDN.

- name: urnd
  address: 2
  read-only: true
  doc: |
    A random number without guaranteed secrecy properties or specific statistical properties.
    Intended for use in masking and blinding schemes.
    Use RND for high-quality randomness.

    The number is sourced from an local PRNG.
    Reads never stall.

- name: acc
  address: 3
  doc: |
    The accumulator register used by the {{#acc-insn-ref BN.MULQACC}} instruction.

- name: key_s0_l
  address: 4
  read-only: true
  doc: |
    Bits [255:0] of share 0 of the 384b ACC sideload key provided by the [Key Manager](../keymgr/README.md).

    A `KEY_INVALID` software error is raised on read if the Key Manager has not provided a valid key.

- name: key_s0_h
  address: 5
  read-only: true
  doc: |
    Bits [255:128] of this register are always zero.
    Bits [127:0] contain bits [383:256] of share 0 of the 384b ACC sideload key provided by the [Key Manager](../keymgr/README.md).

    A `KEY_INVALID` software error is raised on read if the Key Manager has not provided a valid key.

- name: key_s1_l
  address: 6
  read-only: true
  doc: |
    Bits [255:0] of share 1 of the 384b ACC sideload key provided by the [Key Manager](../keymgr/README.md).

    A `KEY_INVALID` software error is raised on read if the Key Manager has not provided a valid key.

- name: key_s1_h
  address: 7
  read-only: true
  doc: |
    Bits [255:128] of this register are always zero.
    Bits [127:0] contain bits [383:256] of share 1 of the 384b ACC sideload key provided by the [Key Manager](../keymgr/README.md).

    A `KEY_INVALID` software error is raised on read if the Key Manager has not provided a valid key.

- name: kmac_cfg
  address: 8
  doc: |
    Contains the configuration bits for sending KMAC messages.
    Also visible as a kmac_cfg CSR.

- name: kmac_msg
  address: 9
  doc: |
    The kmac message data share0 to send over the AppIntf.
    A byte mask is applied to the message from the kmac_partial_write WSR value before being written into the internal MSG FIFO.

- name: kmac_digest
  address: 10
  doc: |
    Return digest share 0 from AppIntf. In unmasked kmac_cfg this is the whole digest.

- name: acch
  address: 11
  doc: |
    The high 256-bits of the accumulator register used by the {{#acc-insn-ref BN.MULV}} instruction.

- name: kmac_msg1
  address: 12
  doc: |
    The kmac message data share1 to send over the AppIntf. In unmasked kmac_cfg writing to this WSR is illegal.
    A byte mask is applied to the message from the kmac_partial_write WSR value before being written into the internal MSG FIFO.

- name: kmac_digest1
  address: 13
  doc: |
    Return digest share 1 from AppIntf. In unmasked kmac_cfg reading from this WSR is illegal.