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#ifndef SPASM_IMPL_HPP
#define SPASM_IMPL_HPP
#include <iostream>
#include <cstdint>
#include <unordered_set>
#include "types.hpp"
namespace SpasmImpl
{
enum OpCodes : char
{
Halt,
Dup,
Pop,
PopTo,
PushFrom,
Push,
Print,
Read,
Call,
Ret,
Jump,
JumpT,
JumpF,
Const,
String,
Add,
Sub,
Mul,
Div,
Mod,
Less,
LessEq,
Greater,
GreaterEq,
Equal,
NotEqual,
LastIndex = NotEqual,
};
static_assert(LastIndex < 0x3f, "Too many opcodes");
class StringTable
{
public:
const SPStringValue* Get(const char* s, size_t length)
{
SPString v(s, length);
auto pos = m_Strings.insert(SPStringValue(v));
return &(*pos.first);
}
private:
typedef std::unordered_set<SPStringValue> StringMap;
StringMap m_Strings;
};
//! The Abstract Stack Machine
/*!
** The machine contains a data stack for operations and control flow and
** frame stack for function calls (including parameter passing) and local
** variables and return stack for the addresses of the returns.
*/
class Spasm
{
public:
Spasm();
void Initialize(PC_t,
const byte*,
std::istream& = std::cin,
std::ostream& = std::cout);
~Spasm();
Spasm(const Spasm&) = delete;
Spasm& operator=(const Spasm&) = delete;
enum RunResult
{
Success,
Exception,
NotImplemented,
};
RunResult run();
private:
//! Program counter - points the current opcode
PC_t m_PC = 0;
typedef SPVector<byte> ByteCode;
//! bytecode of the program
ByteCode m_ByteCode;
typedef SPVector<data_t> DataStack;
//! stack for storing arguments and local variables
DataStack data_stack;
//! Stack pointer - always the top of the stack
data_t* m_SP = nullptr;
//! Frame pointer - the start of the stack for the current function
data_t* m_FP = nullptr;
struct Frame
{
PC_t ReturnAddress;
PC_t FramePointer;
PC_t StackPointer;
};
typedef std::stack<Frame> FrameStack;
//! Stack for function frames
FrameStack m_Frames;
StringTable m_Strings;
//! Input stream for read () operation
std::istream* istr;
//! Output stream for print () opertion
std::ostream* ostr;
void push(reg_t reg);
void popto(reg_t reg);
void dup();
void print(reg_t reg);
void read(reg_t reg);
void plus(reg_t a0, reg_t a1, reg_t a2);
void minus(reg_t a0, reg_t a1, reg_t a2);
void multiply(reg_t a0, reg_t a1, reg_t a2);
void divide(reg_t a0, reg_t a1, reg_t a2);
void modulus(reg_t a0, reg_t a1, reg_t a2);
void gotrue(reg_t a0, reg_t a1);
void gofalse(reg_t a0, reg_t a1);
void go(reg_t a0);
void call(reg_t a0);
void ret(reg_t a0);
void load();
void store();
void less(reg_t a0, reg_t a1, reg_t a2);
void lesseq(reg_t a0, reg_t a1, reg_t a2);
void greater(reg_t a0, reg_t a1, reg_t a2);
void greatereq(reg_t a0, reg_t a1, reg_t a2);
void equal(reg_t a0, reg_t a1, reg_t a2);
void not_equal(reg_t a0, reg_t a1, reg_t a2);
data_t get_local(reg_t reg);
void set_local(reg_t reg, data_t data);
data_t pop_data();
void push_data(data_t);
reg_t read_reg(size_t size);
data_t read_number(size_t size);
int64_t read_integer(size_t size);
data_t read_string(size_t size);
};
} // namespace SpasmImpl
#endif // #ifndef SPASM_IMPL_HPP
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