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// Copyright (c) 2025 taitep
// SPDX-License-Identifier: BSD-2-Clause
//
// This file is part of TRVE (https://gitea.taitep.se/taitep/trve)
// See LICENSE file in the project root for full license text.
#[macro_use]
mod macros;
mod rvi;
mod rvm;
use crate::{
core::Core,
decode::Instruction,
exceptions::{
Exception,
ExceptionType::{self, IllegalInstruction},
},
};
fn illegal(instr: Instruction) -> Result<(), Exception> {
Err(Exception {
type_: IllegalInstruction,
value: instr.0 as u64,
})
}
pub(crate) fn find_and_exec(instr: Instruction, core: &mut Core) -> Result<(), Exception> {
match instr.opcode_noncompressed() {
0b01100 => match (instr.funct3(), instr.funct7()) {
// OP
(0b000, 0b0000000) => rvi::add(core, instr),
(0b000, 0b0100000) => rvi::sub(core, instr),
(0b000, 0b0000001) => rvm::mul(core, instr),
(0b010, 0b0000000) => rvi::slt(core, instr),
(0b011, 0b0000000) => rvi::sltu(core, instr),
(0b001, 0b0000000) => rvi::sll(core, instr),
(0b101, 0b0000000) => rvi::srl(core, instr),
(0b101, 0b0100000) => rvi::sra(core, instr),
(0b111, 0b0000000) => rvi::and(core, instr),
(0b100, 0b0000000) => rvi::xor(core, instr),
(0b100, 0b0000001) => rvm::div(core, instr),
(0b110, 0b0000000) => rvi::or(core, instr),
_ => illegal(instr),
},
0b01110 => match (instr.funct3(), instr.funct7()) {
// OP_32
(0b000, 0b0000000) => rvi::addw(core, instr),
(0b000, 0b0100000) => rvi::subw(core, instr),
(0b001, 0b0000000) => rvi::sllw(core, instr),
(0b101, 0b0000000) => rvi::srlw(core, instr),
(0b101, 0b0100000) => rvi::sraw(core, instr),
_ => illegal(instr),
},
0b00100 => match instr.funct3() {
// OP_IMM
0b000 => rvi::addi(core, instr),
0b010 => rvi::slti(core, instr),
0b011 => rvi::sltiu(core, instr),
0b001 => match instr.funct6() {
0 => rvi::slli(core, instr),
_ => illegal(instr),
},
0b101 => match instr.funct6() {
0b000000 => rvi::srli(core, instr),
0b010000 => rvi::srai(core, instr),
_ => illegal(instr),
},
0b100 => rvi::xori(core, instr),
0b110 => rvi::ori(core, instr),
0b111 => rvi::andi(core, instr),
_ => illegal(instr),
},
0b00110 => match instr.funct3() {
// OP_IMM_32
0b000 => rvi::addiw(core, instr),
0b001 => match instr.funct7() {
0 => rvi::slliw(core, instr),
_ => illegal(instr),
},
0b101 => match instr.funct7() {
0b0000000 => rvi::srliw(core, instr),
0b0100000 => rvi::sraiw(core, instr),
_ => illegal(instr),
},
_ => illegal(instr),
},
0b01000 => match instr.funct3() {
// STORE
0b000 => rvi::sb(core, instr),
0b001 => rvi::sh(core, instr),
0b010 => rvi::sw(core, instr),
0b011 => rvi::sd(core, instr),
_ => illegal(instr),
},
0b00000 => match instr.funct3() {
// LOAD
0b000 => rvi::lb(core, instr),
0b100 => rvi::lbu(core, instr),
0b001 => rvi::lh(core, instr),
0b101 => rvi::lhu(core, instr),
0b010 => rvi::lw(core, instr),
0b110 => rvi::lwu(core, instr),
0b011 => rvi::ld(core, instr),
_ => illegal(instr),
},
0b11000 => match instr.funct3() {
// BRANCH
0b000 => rvi::beq(core, instr),
0b001 => rvi::bne(core, instr),
0b100 => rvi::blt(core, instr),
0b101 => rvi::bge(core, instr),
0b110 => rvi::bltu(core, instr),
0b111 => rvi::bgeu(core, instr),
_ => illegal(instr),
},
0b01101 => rvi::lui(core, instr),
0b00101 => rvi::auipc(core, instr),
0b11011 => rvi::jal(core, instr),
0b11001 => {
if instr.funct3() == 0 {
rvi::jalr(core, instr)
} else {
illegal(instr)
}
}
0b00011 => match instr.funct3() {
// MISC_MEM
0b000 => {
// FENCE is just implemented as a SeqCst fence always here
// I dont yet care about the potential performance issue this may bring
std::sync::atomic::fence(std::sync::atomic::Ordering::SeqCst);
core.advance_pc();
Ok(())
}
_ => illegal(instr),
},
0b11100 => match (instr.funct3(), instr.funct12(), instr.rs1(), instr.rd()) {
(0b000, 0b000000000000, 0, 0) => {
// TODO: When privilege modes are added, make the exception raised by ecall
// depend on privilege mode
Err(ExceptionType::EnvironmentCallFromMMode.with_no_value())
}
(0b000, 0b000000000001, 0, 0) => Err(ExceptionType::Breakpoint.with_no_value()),
_ => {
// Temporarily allowing unrecognized instructions here to be able to run
// the official ISA tests, which perform CSR operations but work just fine
// without them
eprintln!("Unrecognized instruction within SYSTEM opcode");
dbg!(instr);
core.advance_pc();
Ok(())
}
},
_ => illegal(instr),
}
}
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