---

cache.h

#ifndef CACHE_H
#define CACHE_H

#include "vt.h"
#include "misc.h"
#include "dllist.h"

#define HASH_SIZE       113

struct cache
{
    struct dl_head hash[HASH_SIZE];
    int erc;                    /*  error reduction circuit on */
    int npages;
    u16 hi_subno[0x9ff + 1];    /*  0:pg not in cache, 1-3f80:highest subno + 1 */
    struct cache_ops *op;
};

struct cache_page
{
    struct dl_node node[1];
    struct vt_page page[1];
};

struct cache_ops
{
    void (*close)(struct cache *ca);
    struct vt_page *(*get)(struct cache *ca, int pgno, int subno);
    struct vt_page *(*put)(struct cache *ca, struct vt_page *vtp);
    void (*reset)(struct cache *ca);
    struct vt_page *(*foreach_pg)(struct cache *ca, int pgno, int subno,
                                            int dir, int (*func)(), void *data);
    int (*mode)(struct cache *ca, int mode, int arg);
};

struct cache *cache_open(void);

#define CACHE_MODE_ERC  1

#endif

---