/*
 * nanowasm, a tiny WebAssembly/Wasm interpreter
 * Copyright (C) 2023-2025  Xavier Del Campo Romero
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

#include <nanowasm/nw.h>
#include <nw/interp.h>
#include <nw/io.h>
#include <nw/log.h>
#include <nw/ops.h>
#include <nw/routines.h>
#include <nw/stack.h>

static enum nw_state push(struct nw_interp *const i)
{
    struct nw_i_sm_cm *const cm = &i->sm.cm;
    const enum nw_state n = nwp_stack_push(i, &cm->io);

    if (n)
        return n;

    nwp_interp_resume(i);
    return NW_AGAIN;
}

static enum nw_state get_reserved(struct nw_interp *const i)
{
    nw_varuint1 reserved;
    struct nw_i_sm_cm *const cm = &i->sm.cm;
    const struct nw_io_cfg *const cfg = &i->cfg.io;
    const enum nw_state n = nwp_varuint1(cfg, &cm->leb128, &reserved, cfg->user);

    if (n)
        return n;
    else if (reserved)
    {
        static const char *const exc = "invalid reserved value";

        i->exception = exc;
#ifdef NW_LOG
        nwp_log("%s: %#x\n", exc, (unsigned)reserved);
#endif
        return NW_FATAL;
    }
    else
    {
        struct nw_sm_io io = {0};
        nw_varuint32 *const np = &i->linear.n_pages;

        io.buf = np;
        io.n = sizeof *np;
        cm->io = io;
    }

    i->next = push;
    return NW_AGAIN;
}

void nwp_op_current_memory(struct nw_interp *const i)
{
    static const struct nw_i_sm_cm cm;
    struct nw_i_sm_cm *const pcm = &i->sm.cm;

    *pcm = cm;
    i->next = get_reserved;
}