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#include "segment.h"
#include "operators.h"
#include <boost/endian/conversion.hpp>
#include <iostream>
#include <exception>
using namespace std::string_literals;
size_t Segment::getAddressOfLabel(const std::string& label)
{
size_t address{0};
auto i{begin()};
while (i != end()) {
Chunk& chunk{**i};
address += chunk.size();
if (typeid(chunk) == typeid(Label)) {
if (dynamic_cast<Label&>(chunk).name() == label) {
return address;
}
}
i++;
}
throw std::runtime_error("Error: Label |"s + label + "| not found."s);
}
size_t Segment::getAddressOfIndex(size_t index)
{
if (index >= size())
throw std::runtime_error("Error: Index |"s + std::to_string(index) + "| not found."s);
size_t address{0};
for (size_t i = 0; i < index; i++) {
address += (*this)[i]->size();
}
return address;
}
std::vector<uint8_t> Segment::getCode()
{
std::vector<uint8_t> result;
for (const auto& chunk: *this)
result = result + chunk->getCode();
return result;
}
void Segment::insertAddresses()
{
// insert relative addresses
for (size_t i = 0; i < this->size(); i++) {
try {
AddressFeature& af { dynamic_cast<AddressFeature&>(*((*this)[i]))};
if (af.relativeAddressing == false)
throw std::runtime_error("Error: Absolute Addressing not supported.");
int64_t target_address = getAddressOfLabel(af.label); // throws if label not found
int64_t start_address = getAddressOfIndex(i); // throws if out of range
int64_t diff = target_address - start_address;
uint64_t udiff = static_cast<uint64_t>(diff);
if (af.addr_size == 1) {
if (diff < -128 || diff > 127)
throw std::runtime_error("Error: Address too far."s);
af.machine_code[af.addr_offs] = static_cast<uint8_t>(udiff);
} else if (af.addr_size == 4) {
*(reinterpret_cast<uint32_t*>(af.machine_code.data() + af.addr_offs)) = boost::endian::native_to_little(static_cast<uint32_t>(udiff));
} else
throw std::runtime_error("Error: unexpected addr_size: "s + std::to_string(af.addr_size));
} catch (const std::bad_cast& ex) {
// ignore, expected for non-addressing chunks
}
}
}
void Segment::optimize()
{
bool changed{false};
for (size_t i = 0; i < this->size(); i++) {
try {
AddressFeature& af { dynamic_cast<AddressFeature&>(*((*this)[i]))};
if (af.relativeAddressing == false)
throw std::runtime_error("Error: Absolute Addressing not supported.");
if (!af.alternative_code.empty()) {
int64_t target_address = getAddressOfLabel(af.label); // throws if label not found
int64_t start_address = getAddressOfIndex(i); // throws if out of range
int64_t diff = target_address - start_address;
if (af.addr_size == 4 && af.alternative_size == 1 && diff >= -128 && diff <= 127) {
af.machine_code = af.alternative_code;
af.addr_size = af.alternative_size;
af.addr_offs = af.alternative_offs;
af.alternative_code.clear();
af.alternative_size = 0;
af.alternative_offs = 0;
changed = true;
}
}
} catch (const std::bad_cast& ex) {
// ignore, expected for non-addressing chunks
}
}
if (changed)
insertAddresses(); // renumber
}
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