src/routines/start_block.c


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/*
 * 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/routines.h>
#include <nw/types.h>

static enum nw_state get_block_type(struct nw_interp *const i)
{
    nw_varint7 type;
    struct nw_i_sm_sb *const sb = i->state;
    const struct nw_io_cfg *const cfg = &i->cfg.io;
    const enum nw_state n = nwp_varint7(cfg, &sb->leb128, &type, cfg->user);
    enum nw_type block_type;

    if (n)
        return n;
    else if (type != 0x40 && nwp_get_type(type, &block_type))
    {
        static const char *const exc = "invalid block type";

        i->exception = exc;
#ifdef ENABLE_LOG
        nwp_log("%s: %#x\n", exc, (unsigned)type);
#endif
        return NW_FATAL;
    }

    i->fr.block_i++;
    i->next = sb->next;
    return NW_AGAIN;
}

void nwp_start_block(struct nw_interp *const i, struct nw_i_sm_sb *const psb,
    enum nw_state (*const next)(struct nw_interp *))
{
    const struct nw_i_sm_sb sb = {0};

    *psb = sb;
    psb->next = next;
    i->state = psb;
    i->next = get_block_type;
}