/* image.c -- the StarForth nucleus, as its host knows it.  See image.h.
 *
 * Nothing here uses the C library: the bare-metal kernel links this file.
 */
#include "v4/image.h"

int v4_image_born(v4_node *n, v4_exec_state *es, v4_heat *h, const v4_image *im)
{
    if (im->cell_bits != (unsigned)V4_CELL_BITS || im->node_words != (unsigned)V4_NODE_WORDS
        || im->data_ring != (unsigned)V4_DATA_RING || im->ret_ring != (unsigned)V4_RET_RING)
        return 0;

    v4_node_born(n, im->port);
    v4_exec_reset(es);
    v4_heat_reset(h);

    v4_node_console_attach(n, im->console_tx);
    v4_node_console_input_attach(n, im->console_rx, im->console_status);
    v4_node_stack_regs_attach(n, im->dstack_reg, im->rstack_reg);
    v4_node_error_attach(n, im->node_error);
    v4_node_fault_attach(n, im->fault_table);
    return 1;
}

int v4_image_waiting(const v4_node *n, const v4_image *im)
{
    return n->input_pos == n->input_len && n->p >= im->key_start && n->p < im->key_end;
}

void v4_image_seal(v4_node *n, const v4_image *im)
{
    n->mem[im->boot_cells]     = n->mem[im->dp];
    n->mem[im->boot_cells + 1] = n->mem[im->latest];
    n->mem[im->fence]          = (n->mem[im->dp] + 3) / 4;
}

/* FNV-1a over the node's memory below HERE, a cell at a time, low byte
 * first, and then LATEST. */
#define FNV_OFFSET 0xcbf29ce484222325ULL
#define FNV_PRIME  0x00000100000001b3ULL

static uint64_t hash_cell(uint64_t h, v4_cell c)
{
    v4_ucell u = (v4_ucell)c;
    unsigned i;
    for (i = 0; i < V4_CELL_BITS / 8; i++) {
        h ^= (uint64_t)((u >> (8 * i)) & 0xffu);
        h *= FNV_PRIME;
    }
    return h;
}

uint64_t v4_image_dict_hash(const v4_node *n, const v4_image *im)
{
    uint64_t h = FNV_OFFSET;
    v4_cell here = (n->mem[im->dp] + 3) / 4, k;

    if (here < 0) here = 0;
    if (here > (v4_cell)V4_NODE_WORDS) here = (v4_cell)V4_NODE_WORDS;
    for (k = 0; k < here; k++) h = hash_cell(h, n->mem[k]);
    return hash_cell(h, n->mem[im->latest]);
}