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#include <cassert>
#include "assembler.hpp"
#include "bytecode.hpp"
#include "symbol.hpp"
#include "tokenizer.hpp"
namespace SpasmImpl
{
namespace ASM
{
Assembler::Assembler(Lexer::Tokenizer& tokenizer, Bytecode_Stream& bytecode)
: _tokenizer(&tokenizer), _bytecode(&bytecode)
{
}
int get_arg_size(const Lexer::Token args[])
{
int size = 0;
for (int i = 0; i < 3; ++i)
{
switch (args[i].type())
{
case Lexer::Token::Integer:
case Lexer::Token::XInteger:
{
if (args[i].value_int() > 0xffffffff)
{
size = std::max(size, 3);
}
else if (args[i].value_int() > 0xffff)
{
size = std::max(size, 2);
}
else if (args[i].value_int() > 0xff)
{
size = std::max(size, 1);
}
else if (args[i].value_int() < -0xffffffffLL)
{
size = std::max(size, 3);
}
else if (args[i].value_int() < -0xffff)
{
size = std::max(size, 2);
}
else if (args[i].value_int() < -0xff)
{
size = std::max(size, 1);
}
break;
}
case Lexer::Token::FloatingPoint:
{
size = std::max(size, 3);
break;
}
default:
break;
}
}
return size;
}
void Assembler::assemble()
{
Lexer::Token token = _tokenizer->next_token();
while (token.type() != Lexer::Token::EndInput)
{
const auto type = token.type();
if (type >= Lexer::Token::_NotOpCodeBegin)
{
switch (token.type())
{
case Lexer::Token::Ident:
assemble_identifier(token);
break;
case Lexer::Token::Label:
token = _tokenizer->next_token();
assert(token.type() == Lexer::Token::Ident);
_symbols.define(token.value_str(), _bytecode->size());
break;
default:
break;
}
}
else
{
Lexer::Token args[3];
if (type >= Lexer::Token::_OneArgBegin)
{
args[0] = _tokenizer->next_token();
}
if (type >= Lexer::Token::_TwoArgBegin)
{
args[1] = _tokenizer->next_token();
}
if (type >= Lexer::Token::_ThreeArgBegin)
{
args[2] = _tokenizer->next_token();
}
const auto size = get_arg_size(args);
_bytecode->push_opcode(
(Bytecode_Stream::Opcode_t)((size << 6) | token.type()));
const auto arg_size = 1 << size;
if (args[0].type() != Lexer::Token::NotUsed)
{
if (type == Lexer::Token::Call || type == Lexer::Token::Jump)
{
assert(args[0].type() == Lexer::Token::Ident);
assemble_identifier(args[0]);
}
else
{
assert(args[0].type() == Lexer::Token::Integer);
_bytecode->push_integer(args[0].value_int(), arg_size);
}
}
if (args[1].type() != Lexer::Token::NotUsed)
{
if (type == Lexer::Token::JumpF || type == Lexer::Token::JumpT)
{
assert(args[1].type() == Lexer::Token::Ident);
assemble_identifier(args[1]);
}
else
{
if (args[1].type() == Lexer::Token::Integer)
{
_bytecode->push_integer(args[1].value_int(), arg_size);
}
else if (args[1].type() == Lexer::Token::FloatingPoint)
{
_bytecode->push_double(args[1].value_double());
}
else
{
assert(false && "expected a number type");
}
}
}
if (args[2].type() != Lexer::Token::NotUsed)
{
assert(args[2].type() == Lexer::Token::Integer);
_bytecode->push_integer(args[2].value_int(), arg_size);
}
}
token = _tokenizer->next_token();
}
Symbol_Table::const_iterator i = _symbols.begin();
while (i != _symbols.end())
{
backpatch(i->second);
++i;
}
}
void Assembler::backpatch(const Symbol* symbol)
{
Symbol::Positions_t::const_iterator i = symbol->positions_begin();
while (i != symbol->positions_end())
{
_bytecode->set_location(*i, symbol->definition());
++i;
}
}
void Assembler::assemble_identifier(const Lexer::Token& token)
{
Symbol* symbol = _symbols.insert(token.value_str(), _bytecode->size());
_bytecode->push_location(symbol->definition());
}
bool compile(std::istream& istr, Bytecode_Stream& bytecode)
{
Lexer::Tokenizer tokenizer(istr);
Assembler assembler(tokenizer, bytecode);
assembler.assemble();
return true;
}
} // namespace ASM
} // namespace SpasmImpl
|
