/*
 * COPYRIGHT:       GPLv2+ - See COPYING in the top level directory
 * PROJECT:         ReactOS Virtual DOS Machine
 * FILE:            subsystems/mvdm/ntvdm/dos/dos32krnl/emsdrv.h
 * PURPOSE:         DOS EMS Driver
 * PROGRAMMERS:     Aleksandar Andrejevic <theflash AT sdf DOT lonestar DOT org>
 */

#ifndef _EMSDRV_H_
#define _EMSDRV_H_

/* DEFINITIONS ****************************************************************/

#define EMS_VERSION_NUM     0x40
#define EMS_INTERRUPT_NUM   0x67
#define EMS_SEGMENT         0xD000  // Default segment
// Specification: Operating system handle 0x0000; user handles from 0x0001 to 0x00FE
#define EMS_MAX_HANDLES     255
#define EMS_PAGE_BITS       14
#define EMS_PAGE_SIZE       (1 << EMS_PAGE_BITS)
#define EMS_PHYSICAL_PAGES  4

/* 16 MB of EMS memory */
#define EMS_TOTAL_PAGES     1024

#define EMS_STATUS_SUCCESS                  0x00
#define EMS_STATUS_INTERNAL_ERROR           0x80
#define EMS_STATUS_INVALID_HANDLE           0x83
#define EMS_STATUS_UNKNOWN_FUNCTION         0x84
#define EMS_STATUS_NO_MORE_HANDLES          0x85
#define EMS_STATUS_INSUFFICIENT_PAGES       0x88
#define EMS_STATUS_ZERO_PAGES               0x89
#define EMS_STATUS_INV_LOGICAL_PAGE         0x8A
#define EMS_STATUS_INV_PHYSICAL_PAGE        0x8B
#define EMS_STATUS_INVALID_SUBFUNCTION      0x8F
#define EMS_STATUS_HANDLE_NOT_FOUND         0xA0
#define EMS_STATUS_UNNAMED_HANDLE           0xA1
#define EMS_STATUS_HANDLE_ALREADY_EXISTS    0xA1

typedef struct _EMS_HANDLE
{
    BOOLEAN Allocated;
    USHORT PageCount;
    LIST_ENTRY PageList;
    UCHAR Name[8];
} EMS_HANDLE, *PEMS_HANDLE;

typedef struct _EMS_PAGE
{
    LIST_ENTRY Entry;
    USHORT Handle;
} EMS_PAGE, *PEMS_PAGE;

#pragma pack(push, 1)

typedef struct _EMS_HANDLE_PAGE_INFO
{
    USHORT Handle;
    USHORT PageCount;
} EMS_HANDLE_PAGE_INFO, *PEMS_HANDLE_PAGE_INFO;

typedef struct _EMS_HANDLE_DIR_ENTRY
{
    USHORT Handle;
    UCHAR  Name[8];
} EMS_HANDLE_DIR_ENTRY, *PEMS_HANDLE_DIR_ENTRY;

typedef struct _EMS_COPY_DATA
{
    ULONG RegionLength;
    UCHAR SourceType;
    USHORT SourceHandle;
    USHORT SourceOffset;
    USHORT SourceSegment;
    UCHAR DestType;
    USHORT DestHandle;
    USHORT DestOffset;
    USHORT DestSegment;
} EMS_COPY_DATA, *PEMS_COPY_DATA;

typedef struct _EMS_MAPPABLE_PHYS_PAGE
{
    USHORT PageSegment;
    USHORT PageNumber;
} EMS_MAPPABLE_PHYS_PAGE, *PEMS_MAPPABLE_PHYS_PAGE;

typedef struct _EMS_HARDWARE_INFO
{
    WORD RawPageSize;
    WORD AlternateRegSets;
    WORD ContextAreaSize;
    WORD DmaRegisterSets;
    WORD DmaChannelOperation;
} EMS_HARDWARE_INFO, *PEMS_HARDWARE_INFO;

#pragma pack(pop)

/* FUNCTIONS ******************************************************************/

BOOLEAN EmsDrvInitialize(USHORT Segment, ULONG TotalPages);
VOID EmsDrvCleanup(VOID);

#endif /* _EMSDRV_H_ */