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alee-forth/splitmemdict.hpp

97 lines
2.9 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/>.
*/
#ifndef ALEEFORTH_SPLITMEMDICT_HPP
#define ALEEFORTH_SPLITMEMDICT_HPP
#include "alee.hpp"
#include <algorithm>
#ifndef MEMDICTSIZE
#define MEMDICTSIZE (65536)
#endif
constexpr unsigned long int MemDictSize = MEMDICTSIZE;
template<unsigned long int RON>
class SplitMemDict : public Dictionary
{
const uint8_t *rodict;
uint8_t rwdict[MemDictSize - Dictionary::Begin] = {0};
uint8_t extra[Dictionary::Begin];
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Addr convertAddress(Addr addr) const noexcept {
return static_cast<Addr>(addr - (addr >= RON) * RON);
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}
public:
constexpr explicit SplitMemDict(const uint8_t *rod):
rodict(rod)
{
std::copy(rodict, rodict + sizeof(extra), extra);
}
constexpr SplitMemDict(const SplitMemDict<RON>& spd):
SplitMemDict(spd.rodict) {}
constexpr auto& operator=(const SplitMemDict<RON>& spd) {
*this = SplitMemDict(spd.rodict);
return *this;
}
virtual Cell read(Addr addr) const noexcept final {
const uint8_t *dict;
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if (addr < RON)
dict = addr < Dictionary::Begin ? extra : rodict;
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else
dict = rwdict;
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return *reinterpret_cast<const Cell *>(dict + convertAddress(addr));
}
virtual void write(Addr addr, Cell value) noexcept final {
if (addr >= RON)
*reinterpret_cast<Cell *>(rwdict + addr - RON) = value;
else if (addr < Dictionary::Begin)
*reinterpret_cast<Cell *>(extra + addr) = value;
}
virtual uint8_t readbyte(Addr addr) const noexcept final {
const uint8_t *dict;
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if (addr < RON)
dict = addr < Dictionary::Begin ? extra : rodict;
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else
dict = rwdict;
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return dict[convertAddress(addr)];
}
virtual void writebyte(Addr addr, uint8_t value) noexcept final {
if (addr >= RON)
rwdict[addr - RON] = value;
else if (addr < Dictionary::Begin)
extra[addr] = value;
}
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virtual unsigned long int capacity() const noexcept final {
return RON + sizeof(extra) + sizeof(rwdict);
}
};
#endif // ALEEFORTH_SPLITMEMDICT_HPP