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alee-forth/state.cpp

119 lines
2.4 KiB
C++

/**
* 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/>.
*/
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#include "corewords.hpp"
#include "state.hpp"
#include <iterator>
struct pop {};
struct push {};
struct popr {};
struct pushr {};
struct top {};
struct pick {};
bool State::compiling() const
{
return dict.read(Dictionary::Compiling);
}
void State::compiling(bool yes)
{
dict.write(Dictionary::Compiling, yes);
}
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void State::execute(Addr addr)
{
if (addr < Dictionary::Begin) {
// Must be a core-word
CoreWords::run(addr, *this);
} else {
pushr(0);
ip = addr - sizeof(Cell);
do {
ip += sizeof(Cell);
const auto ins = dict.read(ip);
if (!CoreWords::run(ins, *this)) {
pushr(ip);
ip = ins - sizeof(Cell);
}
} while (ip);
}
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}
Cell State::beyondip() const
{
return dict.read(ip + sizeof(Cell));
}
void State::pushr(Cell value)
{
if (rsize() == ReturnStackSize)
throw ::pushr();
*++rsp = value;
}
Cell State::popr()
{
if (rsize() == 0)
throw ::popr();
return *rsp--;
}
void State::push(Cell value)
{
if (size() == DataStackSize)
throw ::push();
*++dsp = value;
}
Cell State::pop()
{
if (size() == 0)
throw ::pop();
return *dsp--;
}
Cell& State::top()
{
if (size() == 0)
throw ::top();
return *dsp;
}
Cell& State::pick(std::size_t i)
{
if (i >= size())
throw ::pick();
return *(dsp - i);
}
std::size_t State::size() const noexcept
{
return std::distance(dstack, static_cast<const Cell *>(dsp)) + 1;
}
std::size_t State::rsize() const noexcept
{
return std::distance(rstack, static_cast<const Cell *>(rsp)) + 1;
}