sprit-forth/source/state.cpp

// sprit-forth: A portable subroutine-threaded Forth.
// Copyright (C) 2024  Clyne Sullivan <clyne@bitgloo.com>
//
// This library is free software; you can redistribute it and/or modify it
// under the terms of the GNU Library General Public License as published by
// the Free Software Foundation; either version 2 of the License, or (at your
// option) any later version.
//
// This library 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 Library General Public License for
// more details.
//
// You should have received a copy of the GNU Library General Public License
// along with this library; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.

#include "core.hpp"
#include "state.hpp"

#include <cstring>

State Forth;

void State::push(Cell value) {
    if (sp >= ds.end())
        Exec.terminate(Error::push);

    *++sp = value;
}

Cell State::pop() {
    if (sp - 1 < ds.begin())
        Exec.terminate(Error::pop);

    return *sp--;
}

void State::rpush(Cell value) {
    if (rp >= rs.end())
        Exec.terminate(Error::rpush);

    *++rp = value;
}

Cell State::rpop() {
    if (rp - 1 < rs.begin())
        Exec.terminate(Error::rpop);

    return *rp--;
}

Word *State::find(const char *s, int len)
{
    for (auto w = latest; w; w = w->link) {
        if (len == (int)strlen(w->name) && strncmp(s, w->name, len) == 0)
            return w;
    }

    return nullptr;
}