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CLK/InstructionSets/ARM/Disassembler.hpp
2024-03-28 10:32:27 -04:00

271 lines
8.9 KiB
C++

//
// Disassembler.hpp
// Clock Signal
//
// Created by Thomas Harte on 19/03/2024.
// Copyright © 2024 Thomas Harte. All rights reserved.
//
#pragma once
#include "OperationMapper.hpp"
#include <string>
#include <sstream>
namespace InstructionSet::ARM {
/// Holds a single ARM operand, whether a source/destination or immediate value, potentially including a shift.
struct Operand {
enum class Type {
Immediate, Register, RegisterList, None
} type = Type::None;
uint32_t value = 0;
// TODO: encode shifting
operator std::string() const {
switch(type) {
default: return "";
case Type::Register: return std::string("r") + std::to_string(value);
case Type::RegisterList: {
std::stringstream stream;
stream << '[';
bool first = true;
for(int c = 0; c < 16; c++) {
if(value & (1 << c)) {
if(!first) stream << ", ";
first = false;
stream << 'r' << c;
}
}
stream << ']';
return stream.str();
}
}
}
};
/// Describes a single ARM instruction, suboptimally but such that all relevant detail has been extracted
/// by the OperationMapper and is now easy to inspect or to turn into a string.
struct Instruction {
Condition condition = Condition::AL;
enum class Operation {
AND, EOR, SUB, RSB,
ADD, ADC, SBC, RSC,
TST, TEQ, CMP, CMN,
ORR, MOV, BIC, MVN,
LDR, STR,
LDM, STM,
B, BL,
SWI,
MRC, MCR,
Undefined,
} operation = Operation::Undefined;
Operand destination, operand1, operand2;
bool sets_flags = false;
bool is_byte = false;
std::string to_string(uint32_t address) const {
std::ostringstream result;
// Treat all nevers as nops.
if(condition == Condition::NV) {
return "nop";
}
// Print operation.
switch(operation) {
case Operation::Undefined: return "undefined";
case Operation::SWI: return "swi";
case Operation::B: result << "b"; break;
case Operation::BL: result << "bl"; break;
case Operation::AND: result << "and"; break;
case Operation::EOR: result << "eor"; break;
case Operation::SUB: result << "sub"; break;
case Operation::RSB: result << "rsb"; break;
case Operation::ADD: result << "add"; break;
case Operation::ADC: result << "adc"; break;
case Operation::SBC: result << "sbc"; break;
case Operation::RSC: result << "rsc"; break;
case Operation::TST: result << "tst"; break;
case Operation::TEQ: result << "teq"; break;
case Operation::CMP: result << "cmp"; break;
case Operation::CMN: result << "cmn"; break;
case Operation::ORR: result << "orr"; break;
case Operation::MOV: result << "mov"; break;
case Operation::BIC: result << "bic"; break;
case Operation::MVN: result << "mvn"; break;
case Operation::LDR: result << "ldr"; break;
case Operation::STR: result << "str"; break;
case Operation::LDM: result << "ldm"; break;
case Operation::STM: result << "stm"; break;
case Operation::MRC: result << "mrc"; break;
case Operation::MCR: result << "mcr"; break;
}
// Append the sets-flags modifier if applicable.
if(sets_flags) result << 's';
// Possibly a condition code.
switch(condition) {
case Condition::EQ: result << "eq"; break;
case Condition::NE: result << "ne"; break;
case Condition::CS: result << "cs"; break;
case Condition::CC: result << "cc"; break;
case Condition::MI: result << "mi"; break;
case Condition::PL: result << "pl"; break;
case Condition::VS: result << "vs"; break;
case Condition::VC: result << "vc"; break;
case Condition::HI: result << "hi"; break;
case Condition::LS: result << "ls"; break;
case Condition::GE: result << "ge"; break;
case Condition::LT: result << "lt"; break;
case Condition::GT: result << "gt"; break;
case Condition::LE: result << "le"; break;
default: break;
}
// If this is a branch, append the target.
if(operation == Operation::B || operation == Operation::BL) {
result << " 0x" << std::hex << ((address + 8 + operand1.value) & 0x3fffffc);
}
if(
operation == Operation::LDR || operation == Operation::STR ||
operation == Operation::LDM || operation == Operation::STM
) {
if(is_byte) result << 'b';
result << ' ' << static_cast<std::string>(destination);
result << ", [" << static_cast<std::string>(operand1) << "]";
// TODO: learn how ARM shifts/etc are normally presented.
}
return result.str();
}
};
/// A target for @c dispatch that merely captures a description of the decoded instruction, being
/// able to vend it later via @c last().
template <Model model>
struct Disassembler {
Instruction last() {
return instruction_;
}
bool should_schedule(Condition condition) {
instruction_ = Instruction();
instruction_.condition = condition;
return true;
}
template <Flags f> void perform(DataProcessing fields) {
constexpr DataProcessingFlags flags(f);
instruction_.operand1.type = Operand::Type::Register;
instruction_.operand1.value = fields.operand1();
instruction_.destination.type = Operand::Type::Register;
instruction_.destination.value = fields.destination();
if(flags.operand2_is_immediate()) {
instruction_.operand2.type = Operand::Type::Immediate;
// instruction_.operand2.value = fields.immediate(), fields.rotate();
// TODO: decode immediate.
} else {
instruction_.operand2.type = Operand::Type::Register;
instruction_.operand2.value = fields.operand2();
// TODO: capture shift_type(), etc.
}
instruction_.sets_flags = flags.set_condition_codes();
switch(flags.operation()) {
case DataProcessingOperation::AND: instruction_.operation = Instruction::Operation::AND; break;
case DataProcessingOperation::EOR: instruction_.operation = Instruction::Operation::EOR; break;
case DataProcessingOperation::ORR: instruction_.operation = Instruction::Operation::ORR; break;
case DataProcessingOperation::BIC: instruction_.operation = Instruction::Operation::BIC; break;
case DataProcessingOperation::MOV: instruction_.operation = Instruction::Operation::MOV; break;
case DataProcessingOperation::MVN: instruction_.operation = Instruction::Operation::MVN; break;
case DataProcessingOperation::TST: instruction_.operation = Instruction::Operation::TST; break;
case DataProcessingOperation::TEQ: instruction_.operation = Instruction::Operation::TEQ; break;
case DataProcessingOperation::ADD: instruction_.operation = Instruction::Operation::ADD; break;
case DataProcessingOperation::ADC: instruction_.operation = Instruction::Operation::ADC; break;
case DataProcessingOperation::CMN: instruction_.operation = Instruction::Operation::CMN; break;
case DataProcessingOperation::SUB: instruction_.operation = Instruction::Operation::SUB; break;
case DataProcessingOperation::SBC: instruction_.operation = Instruction::Operation::SBC; break;
case DataProcessingOperation::CMP: instruction_.operation = Instruction::Operation::CMP; break;
case DataProcessingOperation::RSB: instruction_.operation = Instruction::Operation::RSB; break;
case DataProcessingOperation::RSC: instruction_.operation = Instruction::Operation::RSC; break;
}
}
template <Flags> void perform(Multiply) {}
template <Flags f> void perform(SingleDataTransfer fields) {
constexpr SingleDataTransferFlags flags(f);
instruction_.operation =
(flags.operation() == SingleDataTransferFlags::Operation::STR) ?
Instruction::Operation::STR : Instruction::Operation::LDR;
instruction_.destination.type = Operand::Type::Register;
instruction_.destination.value = fields.destination();
instruction_.operand1.type = Operand::Type::Register;
instruction_.operand1.value = fields.base();
}
template <Flags f> void perform(BlockDataTransfer fields) {
constexpr BlockDataTransferFlags flags(f);
instruction_.operation =
(flags.operation() == BlockDataTransferFlags::Operation::STM) ?
Instruction::Operation::STM : Instruction::Operation::LDM;
instruction_.destination.type = Operand::Type::Register;
instruction_.destination.value = fields.base();
instruction_.operand1.type = Operand::Type::RegisterList;
instruction_.operand1.value = fields.register_list();
}
template <Flags f> void perform(Branch fields) {
constexpr BranchFlags flags(f);
instruction_.operation =
(flags.operation() == BranchFlags::Operation::BL) ?
Instruction::Operation::BL : Instruction::Operation::B;
instruction_.operand1.type = Operand::Type::Immediate;
instruction_.operand1.value = fields.offset();
}
template <Flags f> void perform(CoprocessorRegisterTransfer) {
constexpr CoprocessorRegisterTransferFlags flags(f);
instruction_.operation =
(flags.operation() == CoprocessorRegisterTransferFlags::Operation::MRC) ?
Instruction::Operation::MRC : Instruction::Operation::MCR;
}
template <Flags> void perform(CoprocessorDataOperation) {}
template <Flags> void perform(CoprocessorDataTransfer) {}
void software_interrupt() {
instruction_.operation = Instruction::Operation::SWI;
}
void unknown() {
instruction_.operation = Instruction::Operation::Undefined;
}
private:
Instruction instruction_;
};
}