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#include "interpreter.hpp"
#include <cassert>
#include <stdexcept>
#include <string>
#include "opcodes.hpp"
#include "program.hpp"
namespace Interpreter
{
[[noreturn]] static void abortUnknownCode(int segment, int opcode)
{
const std::string error = "unknown opcode " + std::to_string(opcode) + " in segment " + std::to_string(segment);
throw std::runtime_error(error);
}
[[noreturn]] static void abortUnknownSegment(Type_Code code)
{
const std::string error = "opcode outside of the allocated segment range: " + std::to_string(code);
throw std::runtime_error(error);
}
template <typename T>
auto& getDispatcher(const T& segment, unsigned int seg, int opcode)
{
auto it = segment.find(opcode);
if (it == segment.end())
{
abortUnknownCode(seg, opcode);
}
return it->second;
}
void Interpreter::execute(Type_Code code)
{
unsigned int segSpec = code >> 30;
switch (segSpec)
{
case 0:
{
const int opcode = code >> 24;
const unsigned int arg0 = code & 0xffffff;
return getDispatcher(mSegment0, 0, opcode)->execute(mRuntime, arg0);
}
case 2:
{
const int opcode = (code >> 20) & 0x3ff;
const unsigned int arg0 = code & 0xfffff;
return getDispatcher(mSegment2, 2, opcode)->execute(mRuntime, arg0);
}
}
segSpec = code >> 26;
switch (segSpec)
{
case 0x30:
{
const int opcode = (code >> 8) & 0x3ffff;
const unsigned int arg0 = code & 0xff;
return getDispatcher(mSegment3, 3, opcode)->execute(mRuntime, arg0);
}
case 0x32:
{
const int opcode = code & 0x3ffffff;
return getDispatcher(mSegment5, 5, opcode)->execute(mRuntime);
}
}
abortUnknownSegment(code);
}
void Interpreter::begin()
{
if (mRunning)
{
mCallstack.push(mRuntime);
mRuntime.clear();
}
else
{
mRunning = true;
}
}
void Interpreter::end()
{
if (mCallstack.empty())
{
mRuntime.clear();
mRunning = false;
}
else
{
mRuntime = mCallstack.top();
mCallstack.pop();
}
}
void Interpreter::run(const Program& program, Context& context)
{
begin();
try
{
mRuntime.configure(program, context);
while (mRuntime.getPC() >= 0 && static_cast<std::size_t>(mRuntime.getPC()) < program.mInstructions.size())
{
const Type_Code instruction = program.mInstructions[mRuntime.getPC()];
mRuntime.setPC(mRuntime.getPC() + 1);
execute(instruction);
}
}
catch (...)
{
end();
throw;
}
end();
}
}
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