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/* ScummVM Tools
*
* ScummVM Tools is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include "reassembler.h"
#include "common/endian.h"
Reassembler::Reassembler(InstVec &insts) : Disassembler(insts) { }
void Reassembler::assemble() {
// Prepare to read the input script
_f.seek(0, SEEK_SET);
_binary.clear();
while(!_f.eos()) {
std::string line = readLine();
auto comment = splitString(line, line.find(";"), 1, true);// remove comments
if(line.empty())
continue;
auto label = splitString(line, line.find(": "), 2);
auto instruction = splitString(line, line.find(" "), 1);
if(instruction.empty()) {
// if it didn't find a space, that means there are no arguments
instruction = line;
line = "";
}
std::cout << label << ": " << instruction;
// parse arguments
std::vector<std::string> args;
size_t s = 0, e = 0;
for(s = 0; s < line.length(); s = e + 2) {
if(s > 0) std::cout << ", ";
else std::cout << " ";
e = getEndArgument(line, s);
size_t len = e - s;
args.push_back(line.substr(s, len));
std::cout << args.back();
}
std::cout << "; " << comment << " (" << (boost::format("0x%X") % _binary.size()) << ")\n";
// TODO: maybe parse the arguments into a ValueList of the Value subclasses
doAssembly(label, instruction, args, comment);
}
// 2nd pass in order to set jump addresses after reading all labels
for(const auto &j : _jumps) {
if(j._label.empty())
continue;
size_t addr = 0;
try {
addr = _labels.at(j._label);
} catch(...) {
std::cout << "\nfailed rewriting jump to " << j._label << ", from (" << j.start << ", " << j.len << ")\n";
throw;
}
uint16 u16;
uint32 u32;
switch(j.len) {
case 1:
_binary[j.start] = addr;
break;
case 2:
u16 = TO_LE_16(addr);
_binary[j.start] = u16;
_binary[j.start + 1] = u16 >> 8;
break;
case 4:
u32 = TO_LE_32(addr);
_binary[j.start] = u32;
_binary[j.start + 1] = u32 >> 8;
_binary[j.start + 2] = u32 >> 16;
_binary[j.start + 3] = u32 >> 24;
break;
}
}
}
void Reassembler::doDumpBinary(std::ostream &output) {
output.write((char*)_binary.data(), _binary.size());
}
void Reassembler::dumpBinary(std::ostream &output) {
assemble();
doDumpBinary(output);
}
std::string Reassembler::readLine() {
std::string line;
try {
while(!_f.eos()) {
char c = _f.readByte();
if(c == '\n')
break;
line += c;
}
} catch(Common::FileException &e) {
}
return line;
}
std::string Reassembler::splitString(std::string &from, size_t pos, size_t separator_len, bool reverse) {
if(pos == std::string::npos)
return std::string();
if(reverse) {
// return the right side, from is set to the left side
std::string ret = from.substr(pos + separator_len);
from = from.substr(0, pos);
return ret;
}
// else we return the left side, and from is set to the right side
std::string ret = from.substr(0, pos);
from = from.substr(pos + separator_len);
return ret;
}
void Reassembler::addInstruction(const std::vector<byte> &bytes, int type, size_t jumpAddrStart, size_t jumpAddrLen, const std::string &label, const std::string &jumpToLabel) {
if(!label.empty()) {
if(_labels.count(label)) {
throw std::runtime_error("label: " + label + " already exists");
}
_labels.emplace(label, _binary.size());
}
if(type == kCallInst || type == kCondJumpInst || type == kJumpInst) {
Jump j;
j._label = jumpToLabel;
j.start = jumpAddrStart + _binary.size();
j.len = jumpAddrLen;
_jumps.push_back(j);
}
_binary.insert(_binary.end(), bytes.begin(), bytes.end());
}
size_t Reassembler::getEndArgument(const std::string &s, size_t start) {
int brackets = 0;
for(size_t i = start; i < s.length(); i++) {
switch(s[i]) {
case '[':
brackets++;
break;
case ']':
brackets--;
if(brackets < 0)
return i;
break;
case ',':
if(brackets == 0)
return i;
break;
}
}
return s.length();
}
void Reassembler::splitArrayString(const std::string &arg, std::string &first, std::string &second) {
size_t e = getEndArgument(arg, 2);
first = arg.substr(2, e - 2);
second = arg.substr(e + 2);
second.pop_back();
}
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