source: bootcd/isolinux/syslinux-6.03/com32/include/syslinux/movebits.h

#ifndef _SYSLINUX_MOVEBITS_H
#define _SYSLINUX_MOVEBITS_H

#include <inttypes.h>
#include <stdio.h>
#include <stdbool.h>

typedef uint32_t addr_t;

/*
 * A syslinux_movelist is a linked list of move operations.  The ordering
 * is important, so no sorting requirement can be imposed.
 */
struct syslinux_movelist {
    addr_t dst;
    addr_t src;
    addr_t len;
    struct syslinux_movelist *next;
};

/*
 * A syslinux_memmap is a sorted, linked list of memory regions,
 * guaranteed to satisfy the constraint that no adjacent zones have
 * the same type.  Undefined memory ranges are represented with entries;
 * they have type SMT_UNDEFINED.
 *
 * Note that there is no length field.  The length of a region is obtained
 * by looking at the start of the next entry in the chain.
 */
enum syslinux_memmap_types {
    SMT_ERROR = -2,             /* Internal error token */
    SMT_END = -1,               /* End of list */
    SMT_UNDEFINED = 0,          /* Unknown range */
    SMT_FREE = 1,               /* Available memory */
    SMT_RESERVED,               /* Unusable memory */
    SMT_ALLOC,                  /* Memory allocated by user */
    SMT_ZERO,                   /* Memory that should be zeroed */
    SMT_TERMINAL,               /* Memory to be used as a last resort */
};

struct syslinux_memmap {
    addr_t start;
    enum syslinux_memmap_types type;
    struct syslinux_memmap *next;
};

static inline bool valid_terminal_type(enum syslinux_memmap_types type)
{
    return (type == SMT_FREE) || (type == SMT_TERMINAL);
}

/*
 * moves is computed from "fraglist" and "memmap".  Areas that are
 * to be zeroed should be marked as such in the memmap, not in the
 * fraglist.
 */

int syslinux_compute_movelist(struct syslinux_movelist **movelist,
                              struct syslinux_movelist *fraglist,
                              struct syslinux_memmap *memmap);

struct syslinux_memmap *syslinux_memory_map(void);
void syslinux_free_movelist(struct syslinux_movelist *);
int syslinux_add_movelist(struct syslinux_movelist **,
                          addr_t dst, addr_t src, addr_t len);
int syslinux_allocate_from_list(struct syslinux_movelist **freelist,
                                addr_t dst, addr_t len);
int syslinux_do_shuffle(struct syslinux_movelist *fraglist,
                        struct syslinux_memmap *memmap,
                        addr_t entry_point, addr_t entry_type,
                        uint16_t bootflags);
struct syslinux_memmap *syslinux_target_memmap(struct syslinux_movelist
                                               *fraglist,
                                               struct syslinux_memmap *memmap);

/* Operatons on struct syslinux_memmap */
struct syslinux_memmap *syslinux_init_memmap(void);
int syslinux_add_memmap(struct syslinux_memmap **list,
                        addr_t start, addr_t len,
                        enum syslinux_memmap_types type);
enum syslinux_memmap_types syslinux_memmap_type(struct syslinux_memmap *list,
                                                addr_t start, addr_t len);
int syslinux_memmap_largest(struct syslinux_memmap *list,
                            enum syslinux_memmap_types type,
                            addr_t * start, addr_t * len);
int syslinux_memmap_highest(const struct syslinux_memmap *list,
                            enum syslinux_memmap_types types,
                            addr_t *start, addr_t len,
                            addr_t ceiling, addr_t align);
void syslinux_free_memmap(struct syslinux_memmap *list);
struct syslinux_memmap *syslinux_dup_memmap(struct syslinux_memmap *list);
int syslinux_memmap_find_type(struct syslinux_memmap *list,
                              enum syslinux_memmap_types type,
                              addr_t * start, addr_t * len, addr_t align);
int syslinux_memmap_find(struct syslinux_memmap *mmap,
                         addr_t *base, size_t size,
                         bool relocate, size_t align,
                         addr_t start_min, addr_t start_max,
                         addr_t end_min, addr_t end_max);

/* Debugging functions */
#ifdef DEBUG
void syslinux_dump_movelist(struct syslinux_movelist *ml);
void syslinux_dump_memmap(struct syslinux_memmap *memmap);
#else
#define syslinux_dump_movelist(x) ((void)0)
#define syslinux_dump_memmap(x)   ((void)0)
#endif

#endif /* _SYSLINUX_MOVEBITS_H */