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alee-forth/state.hpp

97 lines
2.2 KiB
C++

2 years ago
/**
* Alee Forth: A portable and concise Forth implementation in modern C++.
* Copyright (C) 2023 Clyne Sullivan <clyne@bitgloo.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#ifndef ALEEFORTH_STATE_HPP
#define ALEEFORTH_STATE_HPP
#include "dictionary.hpp"
#include "types.hpp"
#include <cstddef>
#include <iterator>
constexpr unsigned DataStackSize = 12;
constexpr unsigned ReturnStackSize = 12;
class State
{
Cell dstack[DataStackSize] = {};
Cell rstack[ReturnStackSize] = {};
Cell *dsp = dstack - 1;
Cell *rsp = rstack - 1;
public:
bool compiling = false;
Addr ip = 0;
Pass pass = Pass::None;
Dictionary& dict;
constexpr State(Dictionary& d): dict(d) {}
Cell beyondip() const {
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return dict.read(ip + 1);
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}
void pushr(Cell value) {
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if (rsize() == ReturnStackSize)
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throw;
*++rsp = value;
}
Cell popr() {
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if (rsize() == 0)
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throw;
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return *rsp--;
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}
void push(Cell value) {
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if (size() == DataStackSize)
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throw;
*++dsp = value;
}
Cell pop() {
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if (size() == 0)
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throw;
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return *dsp--;
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}
Cell& top() {
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if (size() == 0)
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throw;
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return *dsp;
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}
Cell& pick(std::size_t i) {
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if (i >= size())
throw;
return *(dsp - i);
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}
std::size_t size() const noexcept {
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return std::distance(dstack, static_cast<const Cell *>(dsp)) + 1;
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}
std::size_t rsize() const noexcept {
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return std::distance(rstack, static_cast<const Cell *>(rsp)) + 1;
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}
};
#endif // ALEEFORTH_STATE_HPP