106 lines
2.8 KiB
Rust
106 lines
2.8 KiB
Rust
// Copyright (c) 2025 taitep
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// SPDX-License-Identifier: BSD-2-Clause
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//
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// This file is part of TRVE (https://gitea.taitep.se/taitep/trve)
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// See LICENSE file in the project root for full license text.
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const MASK_REGISTER: u32 = 0x1f;
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#[derive(Clone, Copy)]
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pub struct Instruction(pub u32);
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impl std::fmt::Debug for Instruction {
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fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
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f.write_fmt(format_args!("{:08x}", self.0))
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}
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}
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#[allow(dead_code)]
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impl Instruction {
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#[inline]
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pub fn opcode(self) -> u8 {
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(self.0 & 0x7f) as u8
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}
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/// Returns the opcode of the instruction, with the last 2 bits stripped away, as they are always 0b11 in a non-compressed instruction
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#[inline]
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pub fn opcode_noncompressed(self) -> u8 {
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debug_assert_eq!(self.0 & 0b11, 0b11, "Compressed (or invalid) opcode");
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(self.0 >> 2 & 0x1f) as u8
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}
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#[inline]
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pub fn rd(self) -> u8 {
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(self.0 >> 7 & MASK_REGISTER) as u8
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}
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#[inline]
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pub fn funct3(self) -> u8 {
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(self.0 >> 12 & 0x7) as u8
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}
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#[inline]
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pub fn rs1(self) -> u8 {
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(self.0 >> 15 & MASK_REGISTER) as u8
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}
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#[inline]
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pub fn rs2(self) -> u8 {
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(self.0 >> 20 & MASK_REGISTER) as u8
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}
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#[inline]
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pub fn funct7(self) -> u8 {
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(self.0 >> 25 & 0x7f) as u8
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}
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#[inline]
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pub fn imm_i(self) -> u64 {
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(self.0 as i32 as i64 >> 20) as u64
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}
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#[inline]
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pub fn imm_s(self) -> u64 {
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let imm_11_5 = (self.0 as i32 as i64 >> 25 << 5) as u64;
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let imm_4_0 = (self.0 >> 7 & 0x1f) as u64;
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imm_11_5 | imm_4_0
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}
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#[inline]
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pub fn imm_b(self) -> u64 {
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let imm_12 = ((self.0 & 0x8000_0000) as i32 as i64 >> (31 - 12)) as u64;
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let imm_10_5 = ((self.0 >> 25 & 0x3f) << 5) as u64;
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let imm_4_1 = ((self.0 >> 8 & 0xf) << 1) as u64;
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let imm_11 = ((self.0 >> 7 & 1) << 11) as u64;
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imm_12 | imm_10_5 | imm_4_1 | imm_11
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}
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#[inline]
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pub fn imm_u(self) -> u64 {
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(self.0 & 0xffff_f000) as i32 as i64 as u64
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}
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#[inline]
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pub fn imm_j(self) -> u64 {
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let imm_20 = ((self.0 & 0x8000_0000) as i32 as i64 >> (31 - 20)) as u64;
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let imm_10_1 = ((self.0 >> 21 & 0x3ff) << 1) as u64;
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let imm_11 = ((self.0 >> 20 & 1) << 11) as u64;
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let imm_19_12 = ((self.0 >> 12 & 0xff) << 12) as u64;
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imm_20 | imm_10_1 | imm_11 | imm_19_12
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}
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/// Technically part of immediate. Only used to determine shift type for immediate shifts afaik
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/// 32bit ones use funct7 in this way
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#[inline]
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pub fn funct6(self) -> u8 {
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(self.0 >> 26 & 0x3f) as u8
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}
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/// Mostly/only used for the SYSTEM opcode
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pub fn funct12(self) -> u16 {
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(self.0 >> 20) as u16
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}
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}
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