| # Copyright lowRISC contributors. |
| # Licensed under the Apache License, Version 2.0, see LICENSE for details. |
| # SPDX-License-Identifier: Apache-2.0 |
| |
| from typing import List |
| |
| from riscvmodel.types import Trace # type: ignore |
| |
| from .flags import FlagGroups |
| from .wsr import WSRFile |
| |
| |
| class CSRFile: |
| '''A model of the CSR file''' |
| def __init__(self) -> None: |
| self.flags = FlagGroups() |
| |
| def read_unsigned(self, wsrs: WSRFile, idx: int) -> int: |
| if idx == 0x7c0: |
| # FLAGS register |
| return self.flags.read_unsigned() |
| |
| if 0x7d0 <= idx <= 0x7d7: |
| # MOD0 .. MOD7. MODi is bits [32*(i+1)-1..32*i] |
| i = idx - 0x7d0 |
| mod_val = wsrs.MOD.read_unsigned() |
| mask32 = (1 << 32) - 1 |
| return (mod_val >> (32 * i)) & mask32 |
| |
| if idx == 0xfc0: |
| # RND register |
| return wsrs.RND.read_u32() |
| |
| raise RuntimeError('Unknown CSR index: {:#x}'.format(idx)) |
| |
| def write_unsigned(self, wsrs: WSRFile, idx: int, value: int) -> None: |
| assert 0 <= value < (1 << 32) |
| |
| if idx == 0x7c0: |
| # FLAGS register |
| self.flags.write_unsigned(value) |
| return |
| |
| if 0x7d0 <= idx <= 0x7d7: |
| # MOD0 .. MOD7. MODi is bits [32*(i+1)-1..32*i]. read,modify,write. |
| i = idx - 0x7d0 |
| old_val = wsrs.MOD.read_unsigned() |
| shifted_mask = ((1 << 32) - 1) << (32 * i) |
| cleared = old_val & ~shifted_mask |
| new_val = cleared | (value << (32 * i)) |
| wsrs.MOD.write_unsigned(new_val) |
| return |
| |
| if idx == 0xfc0: |
| # RND register (writes are ignored) |
| return |
| |
| raise RuntimeError('Unknown CSR index: {:#x}'.format(idx)) |
