/*
 *  Copyright (C) 2020-2023  The DOSBox Staging Team
 *  Copyright (C) 2002-2021  The DOSBox Team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#include "dosbox.h"

#include <algorithm>
#include <cstring>
#include <cstdlib>

#include "callback.h"
#include "mem.h"
#include "paging.h"
#include "bios.h"
#include "keyboard.h"
#include "regs.h"
#include "inout.h"
#include "dos_inc.h"
#include "setup.h"
#include "support.h"
#include "cpu.h"
#include "dma.h"

#define EMM_PAGEFRAME	0xE000
#define EMM_PAGEFRAME4K	((EMM_PAGEFRAME*16)/4096)
#define	EMM_MAX_HANDLES	200				/* 255 Max */
#define EMM_PAGE_SIZE	(16*1024U)
#define EMM_MAX_PAGES	(32 * 1024 / 16 )
#define EMM_MAX_PHYS	4				/* 4 16kb pages in pageframe */

#define EMM_VERSION			0x40
#define EMM_MINOR_VERSION	0x00
//#define EMM_MINOR_VERSION	0x30	// emm386 4.48
#define GEMMIS_VERSION		0x0001	// Version 1.0

#define EMM_SYSTEM_HANDLE	0x0000
#define NULL_HANDLE			0xffff
#define	NULL_PAGE			0xffff

#define ENABLE_VCPI 1
#define ENABLE_V86_STARTUP 0

#define EMM_VOLATILE 0
#define EMM_NONVOLATILE 1

/* EMM errors */
#define EMM_NO_ERROR			0x00
#define EMM_SOFT_MAL			0x80
#define EMM_HARD_MAL			0x81
#define EMM_INVALID_HANDLE		0x83
#define EMM_FUNC_NOSUP			0x84
#define EMM_OUT_OF_HANDLES		0x85
#define EMM_SAVEMAP_ERROR		0x86
#define EMM_OUT_OF_PHYS			0x87
#define EMM_OUT_OF_LOG			0x88
#define EMM_ZERO_PAGES			0x89
#define EMM_LOG_OUT_RANGE		0x8a
#define EMM_ILL_PHYS			0x8b
#define EMM_PAGE_MAP_SAVED		0x8d
#define EMM_NO_SAVED_PAGE_MAP	0x8e
#define EMM_INVALID_SUB			0x8f
#define EMM_ATTR_UNDEF			0x90
#define EMM_FEAT_NOSUP			0x91
#define EMM_MOVE_OVLAP			0x92
#define EMM_MOVE_OVLAPI			0x97
#define EMM_NOT_FOUND			0xa0


struct EMM_Mapping {
	uint16_t handle;
	uint16_t page;
};

struct EMM_Handle {
	uint16_t pages;
	MemHandle mem;
	char name[8];
	bool saved_page_map;
	EMM_Mapping page_map[EMM_MAX_PHYS];
};

static Bitu ems_type;

static EMM_Handle emm_handles[EMM_MAX_HANDLES];
static EMM_Mapping emm_mappings[EMM_MAX_PHYS];
static EMM_Mapping emm_segmentmappings[0x40];


static uint16_t GEMMIS_seg;

class device_EMM final : public DOS_Device {
public:
	device_EMM(bool is_emm386_avail) : is_emm386(is_emm386_avail)
	{
		SetName("EMMXXXX0");
		GEMMIS_seg = 0;
	}

	bool Read(uint8_t* /*data*/, uint16_t* /*size*/) override
	{
		return false;
	}
	bool Write(uint8_t* /*data*/, uint16_t* /*size*/) override
	{
		LOG(LOG_IOCTL, LOG_NORMAL)("EMS:Write to device");
		return false;
	}
	bool Seek(uint32_t* /*pos*/, uint32_t /*type*/) override
	{
		return false;
	}
	bool Close() override
	{
		return false;
	}
	uint16_t GetInformation(void) override
	{
		return 0xc0c0;
	}
	bool ReadFromControlChannel(PhysPt bufptr, uint16_t size,
	                            uint16_t* retcode) override;
	bool WriteToControlChannel(PhysPt /*bufptr*/, uint16_t /*size*/,
	                           uint16_t* /*retcode*/) override
	{
		return true;
	}

private:
	bool is_emm386;
};

bool device_EMM::ReadFromControlChannel(PhysPt bufptr,uint16_t size,uint16_t * retcode) {
	Bitu subfct=mem_readb(bufptr);
	switch (subfct) {
		case 0x00:
			if (size!=6) return false;
			mem_writew(bufptr+0x00,0x0023);		// ID
			mem_writed(bufptr+0x02,0);			// private API entry point
			*retcode=6;
			return true;
		case 0x01: {
			if (!is_emm386) return false;
			if (size!=6) return false;
			if (GEMMIS_seg==0) GEMMIS_seg=DOS_GetMemory(0x20);
			PhysPt GEMMIS_addr=PhysicalMake(GEMMIS_seg,0);

			mem_writew(GEMMIS_addr+0x00,0x0004);			// flags
			mem_writew(GEMMIS_addr+0x02,0x019d);			// size of this structure
			mem_writew(GEMMIS_addr+0x04,GEMMIS_VERSION);	// version 1.0 (provide ems information only)
			mem_writed(GEMMIS_addr+0x06,0);					// reserved

			/* build non-EMS frames (0-0xe000) */
			for (Bitu frct=0; frct<EMM_PAGEFRAME4K/4; frct++) {
				mem_writeb(GEMMIS_addr+0x0a+frct*6,0x00);	// frame type: NONE
				mem_writeb(GEMMIS_addr+0x0b+frct*6,0xff);	// owner: NONE
				mem_writew(GEMMIS_addr+0x0c+frct*6,0xffff);	// non-EMS frame
				mem_writeb(GEMMIS_addr+0x0e + frct*6,0xff);	// EMS page number (NONE)
				mem_writeb(GEMMIS_addr+0x0f+frct*6,0xaa);	// flags: direct mapping
			}
			/* build EMS page frame (0xe000-0xf000) */
			for (Bitu frct=0; frct<0x10/4; frct++) {
				Bitu frnr=(frct+EMM_PAGEFRAME4K/4)*6;
				mem_writeb(GEMMIS_addr+0x0a+frnr,0x03);		// frame type: EMS frame in 64k page
				mem_writeb(GEMMIS_addr+0x0b+frnr,0xff);		// owner: NONE
				mem_writew(GEMMIS_addr+0x0c+frnr,0x7fff);	// no logical page number
				mem_writeb(GEMMIS_addr+0x0e + frnr,(uint8_t)(frct&0xff));		// physical EMS page number
				mem_writeb(GEMMIS_addr+0x0f+frnr,0x00);		// EMS frame
			}
			/*
			build non-EMS ROM frames (0xf000-0x10000)
			Note: This is dead code, because frct is always >= 60

 			for (Bitu frct=(EMM_PAGEFRAME4K+0x10)/4; frct<0xf0/4; frct++) {
				mem_writeb(GEMMIS_addr+0x0a+frct*6,0x00);	// frame type: NONE
				mem_writeb(GEMMIS_addr+0x0b+frct*6,0xff);	// owner: NONE
				mem_writew(GEMMIS_addr+0x0c+frct*6,0xffff);	// non-EMS frame
				mem_writeb(GEMMIS_addr+0x0e + frct*6,0xff);	// EMS page number (NONE)
				mem_writeb(GEMMIS_addr+0x0f+frct*6,0xaa);	// flags: direct mapping
			}
			*/

			mem_writeb(GEMMIS_addr+0x18a,0x74);			// ???
			mem_writeb(GEMMIS_addr+0x18b,0x00);			// no UMB descriptors following
			mem_writeb(GEMMIS_addr+0x18c,0x01);			// 1 EMS handle info recort
			mem_writew(GEMMIS_addr+0x18d,0x0000);		// system handle
			mem_writed(GEMMIS_addr+0x18f,0);			// handle name
			mem_writed(GEMMIS_addr+0x193,0);			// handle name
			if (emm_handles[EMM_SYSTEM_HANDLE].pages != NULL_HANDLE) {
				mem_writew(GEMMIS_addr+0x197,(emm_handles[EMM_SYSTEM_HANDLE].pages+3)/4);
				mem_writed(GEMMIS_addr+0x199,emm_handles[EMM_SYSTEM_HANDLE].mem<<12);	// physical address
			} else {
				mem_writew(GEMMIS_addr+0x197,0x0001);		// system handle
				mem_writed(GEMMIS_addr+0x199,0x00110000);	// physical address
			}

			/* fill buffer with import structure */
			mem_writed(bufptr+0x00,GEMMIS_seg<<4);
			mem_writew(bufptr+0x04,GEMMIS_VERSION);
			*retcode=6;
			return true;
			}
		case 0x02:
			if (!is_emm386) return false;
			if (size!=2) return false;
			mem_writeb(bufptr+0x00,EMM_VERSION>>4);		// version 4
			mem_writeb(bufptr+0x01,EMM_MINOR_VERSION);
			*retcode=2;
			return true;
		case 0x03:
			if (!is_emm386) return false;
			if (EMM_MINOR_VERSION < 0x2d) return false;
			if (size!=4) return false;
			mem_writew(bufptr+0x00,(uint16_t)(MEM_TotalPages()*4));	// max size (kb)
			mem_writew(bufptr+0x02,0x80);							// min size (kb)
			*retcode=2;
			return true;
	}
	return false;
}

static struct {
	bool enabled;
	uint16_t ems_handle;
	Bitu pm_interface;
	MemHandle private_area;
	uint8_t pic1_remapping,pic2_remapping;
} vcpi ;

struct MoveRegion {
	uint32_t bytes;
	uint8_t src_type;
	uint16_t src_handle;
	uint16_t src_offset;
	uint16_t src_page_seg;
	uint8_t dest_type;
	uint16_t dest_handle;
	uint16_t dest_offset;
	uint16_t dest_page_seg;
};

static uint16_t EMM_GetFreePages(void) {
	Bitu count=MEM_FreeTotal()/4;
	if (count>0x7fff) count=0x7fff;
	return (uint16_t)count;
}

static bool inline ValidHandle(uint16_t handle) {
	if (handle>=EMM_MAX_HANDLES) return false;
	if (emm_handles[handle].pages==NULL_HANDLE) return false;
	return true;
}

static uint8_t EMM_AllocateMemory(uint16_t pages,uint16_t & dhandle,bool can_allocate_zpages) {
	/* Check for 0 page allocation */
	if (!pages) {
		if (!can_allocate_zpages) return EMM_ZERO_PAGES;
	}
	/* Check for enough free pages */
	if ((MEM_FreeTotal()/ 4) < pages) { return EMM_OUT_OF_LOG;}
	uint16_t handle = 1;
	/* Check for a free handle */
	while (emm_handles[handle].pages != NULL_HANDLE) {
		if (++handle >= EMM_MAX_HANDLES) {return EMM_OUT_OF_HANDLES;}
	}
	MemHandle mem = 0;
	if (pages) {
		mem = MEM_AllocatePages(pages*4,false);
		if (!mem) E_Exit("EMS:Memory allocation failure");
	}
	emm_handles[handle].pages = pages;
	emm_handles[handle].mem = mem;
	/* Change handle only if there is no error. */
	dhandle = handle;
	return EMM_NO_ERROR;
}

static uint8_t EMM_AllocateSystemHandle(uint16_t pages) {
	/* Check for enough free pages */
	if ((MEM_FreeTotal()/ 4) < pages) { return EMM_OUT_OF_LOG;}
	uint16_t handle = EMM_SYSTEM_HANDLE;	// emm system handle (reserved for OS usage)
	/* Release memory if already allocated */
	if (emm_handles[handle].pages != NULL_HANDLE) {
		MEM_ReleasePages(emm_handles[handle].mem);
	}
	MemHandle mem = MEM_AllocatePages(pages*4,false);
	if (!mem) E_Exit("EMS:System handle memory allocation failure");
	emm_handles[handle].pages = pages;
	emm_handles[handle].mem = mem;
	return EMM_NO_ERROR;
}

static uint8_t EMM_ReallocatePages(uint16_t handle,uint16_t & pages) {
	/* Check for valid handle */
	if (!ValidHandle(handle)) return EMM_INVALID_HANDLE;
	if (emm_handles[handle].pages != 0) {
		/* Check for enough pages */
		if (!MEM_ReAllocatePages(emm_handles[handle].mem,pages*4,false)) return EMM_OUT_OF_LOG;
	} else {
		MemHandle mem = MEM_AllocatePages(pages*4,false);
		if (!mem) E_Exit("EMS:Memory allocation failure during reallocation");
		emm_handles[handle].mem = mem;
	}
	/* Update size */
	emm_handles[handle].pages=pages;
	return EMM_NO_ERROR;
}

static uint8_t EMM_MapPage(Bitu phys_page,uint16_t handle,uint16_t log_page) {
//	LOG_MSG("EMS MapPage handle %d phys %d log %d",handle,phys_page,log_page);
	/* Check for too high physical page */
	if (phys_page>=EMM_MAX_PHYS) return EMM_ILL_PHYS;

	/* unmapping doesn't need valid handle (as handle isn't used) */
	if (log_page==NULL_PAGE) {
		/* Unmapping */
		emm_mappings[phys_page].handle=NULL_HANDLE;
		emm_mappings[phys_page].page=NULL_PAGE;
		for (Bitu i=0;i<4;i++)
			PAGING_MapPage(EMM_PAGEFRAME4K+phys_page*4+i,EMM_PAGEFRAME4K+phys_page*4+i);
		PAGING_ClearTLB();
		return EMM_NO_ERROR;
	}
	/* Check for valid handle */
	if (!ValidHandle(handle)) return EMM_INVALID_HANDLE;

	if (log_page<emm_handles[handle].pages) {
		/* Mapping it is */
		emm_mappings[phys_page].handle=handle;
		emm_mappings[phys_page].page=log_page;

		MemHandle memh=MEM_NextHandleAt(emm_handles[handle].mem,log_page*4);;
		for (Bitu i=0;i<4;i++) {
			PAGING_MapPage(EMM_PAGEFRAME4K+phys_page*4+i,memh);
			memh=MEM_NextHandle(memh);
		}
		PAGING_ClearTLB();
		return EMM_NO_ERROR;
	} else  {
		/* Illegal logical page it is */
		return EMM_LOG_OUT_RANGE;
	}
}

static uint8_t EMM_MapSegment(Bitu segment,uint16_t handle,uint16_t log_page) {
//	LOG_MSG("EMS MapSegment handle %d segment %d log %d",handle,segment,log_page);

	bool valid_segment=false;

	if ((ems_type==1) || (ems_type==3)) {
		if (segment<0xf000+0x1000) valid_segment=true;
	} else {
		if ((segment>=0xa000) && (segment<0xb000)) {
			valid_segment=true;		// allow mapping of graphics memory
		}
		if ((segment>=EMM_PAGEFRAME) && (segment<EMM_PAGEFRAME+0x1000)) {
			valid_segment=true;		// allow mapping of EMS page frame
		}
/*		if ((segment>=EMM_PAGEFRAME-0x1000) && (segment<EMM_PAGEFRAME)) {
			valid_segment=true;
		} */
	}

	if (valid_segment) {
		int32_t tphysPage = ((int32_t)segment-EMM_PAGEFRAME)/(0x1000/EMM_MAX_PHYS);

		/* unmapping doesn't need valid handle (as handle isn't used) */
		if (log_page==NULL_PAGE) {
			/* Unmapping */
			if ((tphysPage>=0) && (tphysPage<EMM_MAX_PHYS)) {
				emm_mappings[tphysPage].handle=NULL_HANDLE;
				emm_mappings[tphysPage].page=NULL_PAGE;
			} else {
				emm_segmentmappings[segment>>10].handle=NULL_HANDLE;
				emm_segmentmappings[segment>>10].page=NULL_PAGE;
			}
			for (Bitu i=0;i<4;i++)
				PAGING_MapPage(segment*16/4096+i,segment*16/4096+i);
			PAGING_ClearTLB();
			return EMM_NO_ERROR;
		}
		/* Check for valid handle */
		if (!ValidHandle(handle)) return EMM_INVALID_HANDLE;

		if (log_page<emm_handles[handle].pages) {
			/* Mapping it is */
			if ((tphysPage>=0) && (tphysPage<EMM_MAX_PHYS)) {
				emm_mappings[tphysPage].handle=handle;
				emm_mappings[tphysPage].page=log_page;
			} else {
				emm_segmentmappings[segment>>10].handle=handle;
				emm_segmentmappings[segment>>10].page=log_page;
			}

			MemHandle memh=MEM_NextHandleAt(emm_handles[handle].mem,log_page*4);;
			for (Bitu i=0;i<4;i++) {
				PAGING_MapPage(segment*16/4096+i,memh);
				memh=MEM_NextHandle(memh);
			}
			PAGING_ClearTLB();
			return EMM_NO_ERROR;
		} else  {
			/* Illegal logical page it is */
			return EMM_LOG_OUT_RANGE;
		}
	}

	return EMM_ILL_PHYS;
}

static uint8_t EMM_ReleaseMemory(uint16_t handle) {
	/* Check for valid handle */
	if (!ValidHandle(handle)) return EMM_INVALID_HANDLE;

	// should check for saved_page_map flag here, returning an error if it's true
	// as apps are required to restore the pagemap beforehand; to be checked
//	if (emm_handles[handle].saved_page_map) return EMM_SAVEMAP_ERROR;

	if (emm_handles[handle].pages != 0) {
		MEM_ReleasePages(emm_handles[handle].mem);
	}
	/* Reset handle */
	emm_handles[handle].mem=0;
	if (handle==0) {
		emm_handles[handle].pages=0;	// OS handle is NEVER deallocated
	} else {
		emm_handles[handle].pages=NULL_HANDLE;
	}
	emm_handles[handle].saved_page_map=false;
	memset(&emm_handles[handle].name,0,8);
	return EMM_NO_ERROR;
}

static uint8_t EMM_SavePageMap(uint16_t handle) {
	/* Check for valid handle */
	if (handle>=EMM_MAX_HANDLES || emm_handles[handle].pages==NULL_HANDLE) {
		if (handle!=0) return EMM_INVALID_HANDLE;
	}
	/* Check for previous save */
	if (emm_handles[handle].saved_page_map) return EMM_PAGE_MAP_SAVED;
	/* Copy the mappings over */
	for (Bitu i=0;i<EMM_MAX_PHYS;i++) {
		emm_handles[handle].page_map[i].page=emm_mappings[i].page;
		emm_handles[handle].page_map[i].handle=emm_mappings[i].handle;
	}
	emm_handles[handle].saved_page_map=true;
	return EMM_NO_ERROR;
}

static uint8_t EMM_RestoreMappingTable(void) {
	/* Move through the mappings table and setup mapping accordingly */
	for (Bitu i=0;i<0x40;i++) {
		/* Skip the pageframe */
		if ((i>=EMM_PAGEFRAME/0x400) && (i<(EMM_PAGEFRAME/0x400)+EMM_MAX_PHYS)) continue;
		EMM_MapSegment(i << 10, emm_segmentmappings[i].handle,
		               emm_segmentmappings[i].page);
	}
	for (Bitu i=0;i<EMM_MAX_PHYS;i++) {
		EMM_MapPage(i, emm_mappings[i].handle, emm_mappings[i].page);
	}
	return EMM_NO_ERROR;
}
static uint8_t EMM_RestorePageMap(uint16_t handle) {
	/* Check for valid handle */
	if (handle>=EMM_MAX_HANDLES || emm_handles[handle].pages==NULL_HANDLE) {
		if (handle!=0) return EMM_INVALID_HANDLE;
	}
	/* Check for previous save */
	if (!emm_handles[handle].saved_page_map) return EMM_NO_SAVED_PAGE_MAP;
	/* Restore the mappings */
	emm_handles[handle].saved_page_map=false;
	for (Bitu i=0;i<EMM_MAX_PHYS;i++) {
		emm_mappings[i].page=emm_handles[handle].page_map[i].page;
		emm_mappings[i].handle=emm_handles[handle].page_map[i].handle;
	}
	return EMM_RestoreMappingTable();
}

static uint8_t EMM_GetPagesForAllHandles(PhysPt table,uint16_t & handles) {
	handles=0;
	for (uint16_t i=0;i<EMM_MAX_HANDLES;i++) {
		if (emm_handles[i].pages!=NULL_HANDLE) {
			handles++;
			mem_writew(table,i);
			mem_writew(table+2,emm_handles[i].pages);
			table+=4;
		}
	}
	return EMM_NO_ERROR;
}

static uint8_t EMM_PartialPageMapping(void) {
	PhysPt list,data;uint16_t count;
	switch (reg_al) {
	case 0x00:	/* Save Partial Page Map */
		list = SegPhys(ds)+reg_si;
		data = SegPhys(es)+reg_di;
		count=mem_readw(list);list+=2;
		mem_writew(data,count);data+=2;
		for (;count>0;count--) {
			uint16_t segment=mem_readw(list);list+=2;
			if ((segment>=EMM_PAGEFRAME) && (segment<EMM_PAGEFRAME+0x1000)) {
				uint16_t page = (segment-EMM_PAGEFRAME) / (EMM_PAGE_SIZE>>4);
				mem_writew(data,segment);data+=2;
				MEM_BlockWrite(data,&emm_mappings[page],sizeof(EMM_Mapping));
				data+=sizeof(EMM_Mapping);
			} else if ((ems_type==1) || (ems_type==3) || ((segment>=EMM_PAGEFRAME-0x1000) && (segment<EMM_PAGEFRAME)) || ((segment>=0xa000) && (segment<0xb000))) {
				mem_writew(data,segment);data+=2;
				MEM_BlockWrite(data,&emm_segmentmappings[segment>>10],sizeof(EMM_Mapping));
				data+=sizeof(EMM_Mapping);
			} else {
				return EMM_ILL_PHYS;
			}
		}
		break;
	case 0x01:	/* Restore Partial Page Map */
		data = SegPhys(ds)+reg_si;
		count= mem_readw(data);data+=2;
		for (;count>0;count--) {
			uint16_t segment=mem_readw(data);data+=2;
			if ((segment>=EMM_PAGEFRAME) && (segment<EMM_PAGEFRAME+0x1000)) {
				uint16_t page = (segment-EMM_PAGEFRAME) / (EMM_PAGE_SIZE>>4);
				MEM_BlockRead(data,&emm_mappings[page],sizeof(EMM_Mapping));
			} else if ((ems_type==1) || (ems_type==3) || ((segment>=EMM_PAGEFRAME-0x1000) && (segment<EMM_PAGEFRAME)) || ((segment>=0xa000) && (segment<0xb000))) {
				MEM_BlockRead(data,&emm_segmentmappings[segment>>10],sizeof(EMM_Mapping));
			} else {
				return EMM_ILL_PHYS;
			}
			data+=sizeof(EMM_Mapping);
		}
		return EMM_RestoreMappingTable();
		break;
	case 0x02:	/* Get Partial Page Map Array Size */
		reg_al=(uint8_t)(2+reg_bx*(2+sizeof(EMM_Mapping)));
		break;
	default:
		LOG(LOG_MISC,LOG_ERROR)("EMS:Call %2X Subfunction %2X not supported",reg_ah,reg_al);
		return EMM_FUNC_NOSUP;
	}
	return EMM_NO_ERROR;
}

static uint8_t HandleNameSearch(void) {
	char name[9];
	uint16_t handle=0;PhysPt data;
	switch (reg_al) {
	case 0x00:	/* Get all handle names */
		reg_al=0;data=SegPhys(es)+reg_di;
		for (handle=0;handle<EMM_MAX_HANDLES;handle++) {
			if (emm_handles[handle].pages!=NULL_HANDLE) {
				reg_al++;
				mem_writew(data,handle);
				MEM_BlockWrite(data+2,emm_handles[handle].name,8);
				data+=10;
			}
		}
		break;
	case 0x01: /* Search for a handle name */
		MEM_StrCopy(SegPhys(ds)+reg_si,name,8);name[8]=0;
		for (handle=0;handle<EMM_MAX_HANDLES;handle++) {
			if (emm_handles[handle].pages!=NULL_HANDLE) {
				if (!strncmp(name,emm_handles[handle].name,8)) {
					reg_dx=handle;
					return EMM_NO_ERROR;
				}
			}
		}
		return EMM_NOT_FOUND;
		break;
	case 0x02: /* Get Total number of handles */
		reg_bx=EMM_MAX_HANDLES;
		break;
	default:
		LOG(LOG_MISC,LOG_ERROR)("EMS:Call %2X Subfunction %2X not supported",reg_ah,reg_al);
		return EMM_INVALID_SUB;
	}
	return EMM_NO_ERROR;
}

static uint8_t GetSetHandleName(void) {
	uint16_t handle=reg_dx;
	switch (reg_al) {
	case 0x00:	/* Get Handle Name */
		if (handle>=EMM_MAX_HANDLES || emm_handles[handle].pages==NULL_HANDLE) return EMM_INVALID_HANDLE;
		MEM_BlockWrite(SegPhys(es)+reg_di,emm_handles[handle].name,8);
		break;
	case 0x01:	/* Set Handle Name */
		if (handle>=EMM_MAX_HANDLES || emm_handles[handle].pages==NULL_HANDLE) return EMM_INVALID_HANDLE;
		MEM_BlockRead(SegPhys(es)+reg_di,emm_handles[handle].name,8);
		break;
	default:
		LOG(LOG_MISC,LOG_ERROR)("EMS:Call %2X Subfunction %2X not supported",reg_ah,reg_al);
		return EMM_INVALID_SUB;
	}
	return EMM_NO_ERROR;

}

static uint8_t GetSetHandleAttributes(void) {
	switch (reg_al) {
	case 0x00:	// Get handle attribubtes
		if (!ValidHandle(reg_dx)) return EMM_INVALID_HANDLE;
		reg_al = EMM_VOLATILE;	// We only support volatile
		break;
	case 0x01:	// Set handle attributes
		if (!ValidHandle(reg_dx)) return EMM_INVALID_HANDLE;
		switch (reg_bl) {
		case EMM_VOLATILE:
			break;
		case EMM_NONVOLATILE:
			return EMM_FEAT_NOSUP;
		default:
			return EMM_ATTR_UNDEF;
		}
		break;
	case 0x02:	// Get attribute capability
		reg_al = EMM_VOLATILE;	// We only support volatile
		break;
	default:
		LOG(LOG_MISC,LOG_ERROR)("EMS:Call %2X Subfunction %2X not supported",reg_ah,reg_al);
		return EMM_INVALID_SUB;			
	}
	return EMM_NO_ERROR;
}

static void LoadMoveRegion(PhysPt data,MoveRegion & region) {
	region.bytes=mem_readd(data+0x0);

	region.src_type=mem_readb(data+0x4);
	region.src_handle=mem_readw(data+0x5);
	region.src_offset=mem_readw(data+0x7);
	region.src_page_seg=mem_readw(data+0x9);

	region.dest_type=mem_readb(data+0xb);
	region.dest_handle=mem_readw(data+0xc);
	region.dest_offset=mem_readw(data+0xe);
	region.dest_page_seg=mem_readw(data+0x10);
}

static uint8_t MemoryRegion()
{
	MoveRegion region;

	if (reg_al>1) {
		LOG(LOG_MISC,LOG_ERROR)("EMS:Call %2X Subfunction %2X not supported",reg_ah,reg_al);
		return EMM_FUNC_NOSUP;
	}
	LoadMoveRegion(SegPhys(ds)+reg_si,region);
	/* Parse the region for information */
	PhysPt src_mem = 0,dest_mem = 0;
	MemHandle src_handle = 0,dest_handle = 0;
	Bitu src_off = 0,dest_off = 0 ;Bitu src_remain = 0,dest_remain = 0;
	if (!region.src_type) {
		src_mem=region.src_page_seg*16+region.src_offset;
	} else {
		if (!ValidHandle(region.src_handle)) return EMM_INVALID_HANDLE;
		if ((emm_handles[region.src_handle].pages*EMM_PAGE_SIZE) < ((region.src_page_seg*EMM_PAGE_SIZE)+region.src_offset+region.bytes)) return EMM_LOG_OUT_RANGE;
		src_handle=emm_handles[region.src_handle].mem;
		Bitu pages=region.src_page_seg*4+(region.src_offset/MEM_PAGE_SIZE);
		for (;pages>0;pages--) src_handle=MEM_NextHandle(src_handle);
		src_off=region.src_offset&(MEM_PAGE_SIZE-1);
		src_remain=MEM_PAGE_SIZE-src_off;
	}
	if (!region.dest_type) {
		dest_mem=region.dest_page_seg*16+region.dest_offset;
	} else {
		if (!ValidHandle(region.dest_handle)) return EMM_INVALID_HANDLE;
		if (emm_handles[region.dest_handle].pages*EMM_PAGE_SIZE < (region.dest_page_seg*EMM_PAGE_SIZE)+region.dest_offset+region.bytes) return EMM_LOG_OUT_RANGE;
		dest_handle=emm_handles[region.dest_handle].mem;
		Bitu pages=region.dest_page_seg*4+(region.dest_offset/MEM_PAGE_SIZE);
		for (;pages>0;pages--) dest_handle=MEM_NextHandle(dest_handle);
		dest_off=region.dest_offset&(MEM_PAGE_SIZE-1);
		dest_remain=MEM_PAGE_SIZE-dest_off;
	}

	uint8_t buf_src[MEM_PAGE_SIZE];
	uint8_t buf_dest[MEM_PAGE_SIZE];

	while (region.bytes > 0) {
		const size_t toread = std::min<size_t>(region.bytes, MEM_PAGE_SIZE);

		/* Read from the source */
		if (!region.src_type) {
			MEM_BlockRead(src_mem,buf_src,toread);
		} else {
			assert(toread <= MEM_PAGE_SIZE);
			if (toread <= src_remain) {
				MEM_BlockRead((src_handle*MEM_PAGE_SIZE)+src_off,buf_src,toread);
			} else {
				MEM_BlockRead((src_handle*MEM_PAGE_SIZE)+src_off,buf_src,src_remain);
				MEM_BlockRead((MEM_NextHandle(src_handle)*MEM_PAGE_SIZE),&buf_src[src_remain],toread-src_remain);
			}
		}
		/* Check for a move */
		if (reg_al==1) {
			/* Read from the destination */
			if (!region.dest_type) {
				MEM_BlockRead(dest_mem,buf_dest,toread);
			} else {
				assert(toread <= MEM_PAGE_SIZE);
				if (toread <= dest_remain) {
					MEM_BlockRead((dest_handle*MEM_PAGE_SIZE)+dest_off,buf_dest,toread);
				} else {
					MEM_BlockRead((dest_handle*MEM_PAGE_SIZE)+dest_off,buf_dest,dest_remain);
					MEM_BlockRead((MEM_NextHandle(dest_handle)*MEM_PAGE_SIZE),&buf_dest[dest_remain],toread-dest_remain);
				}
			}
			/* Write to the source */
			if (!region.src_type) {
				MEM_BlockWrite(src_mem,buf_dest,toread);
			} else {
				assert(toread <= MEM_PAGE_SIZE);
				if (toread <= src_remain) {
					MEM_BlockWrite((src_handle*MEM_PAGE_SIZE)+src_off,buf_dest,toread);
				} else {
					MEM_BlockWrite((src_handle*MEM_PAGE_SIZE)+src_off,buf_dest,src_remain);
					MEM_BlockWrite((MEM_NextHandle(src_handle)*MEM_PAGE_SIZE),&buf_dest[src_remain],toread-src_remain);
				}
			}
		}
		/* Write to the destination */
		if (!region.dest_type) {
			MEM_BlockWrite(dest_mem,buf_src,toread);
		} else {
			assert(toread <= MEM_PAGE_SIZE);
			if (toread <= dest_remain) {
				MEM_BlockWrite((dest_handle*MEM_PAGE_SIZE)+dest_off,buf_src,toread);
			} else {
				MEM_BlockWrite((dest_handle*MEM_PAGE_SIZE)+dest_off,buf_src,dest_remain);
				MEM_BlockWrite((MEM_NextHandle(dest_handle)*MEM_PAGE_SIZE),&buf_src[dest_remain],toread-dest_remain);
			}
		}
		/* Advance the pointers */
		if (!region.src_type) src_mem+=toread;
		else src_handle=MEM_NextHandle(src_handle);
		if (!region.dest_type) dest_mem+=toread;
		else dest_handle=MEM_NextHandle(dest_handle);
		region.bytes-=toread;
	}
	return EMM_NO_ERROR;
}

static Bitu INT67_Handler(void) {
	Bitu i;
	switch (reg_ah) {
	case 0x40:		/* Get Status */
		reg_ah=EMM_NO_ERROR;
		break;
	case 0x41:		/* Get PageFrame Segment */
		reg_bx=EMM_PAGEFRAME;
		reg_ah=EMM_NO_ERROR;
		break;
	case 0x42:		/* Get number of pages */
		reg_dx=(uint16_t)(MEM_TotalPages()/4);		//Not entirely correct but okay
		reg_bx=EMM_GetFreePages();
		reg_ah=EMM_NO_ERROR;
		break;
	case 0x43:		/* Get Handle and Allocate Pages */
		reg_ah=EMM_AllocateMemory(reg_bx,reg_dx,false);
		break;
	case 0x44:		/* Map Expanded Memory Page */
		reg_ah=EMM_MapPage(reg_al,reg_dx,reg_bx);
		break;
	case 0x45:		/* Release handle and free pages */
		reg_ah=EMM_ReleaseMemory(reg_dx);
		break;
	case 0x46:		/* Get EMM Version */
		reg_ah=EMM_NO_ERROR;
		reg_al=EMM_VERSION;
		break;
	case 0x47:		/* Save Page Map */
		reg_ah=EMM_SavePageMap(reg_dx);
		break;
	case 0x48:		/* Restore Page Map */
		reg_ah=EMM_RestorePageMap(reg_dx);
		break;
	case 0x4b:		/* Get Handle Count */
		reg_bx=0;
		for (i=0;i<EMM_MAX_HANDLES;i++) if (emm_handles[i].pages!=NULL_HANDLE) reg_bx++;
		reg_ah=EMM_NO_ERROR;
		break;
	case 0x4c:		/* Get Pages for one Handle */
		if (!ValidHandle(reg_dx)) {reg_ah=EMM_INVALID_HANDLE;break;}
		reg_bx=emm_handles[reg_dx].pages;
		reg_ah=EMM_NO_ERROR;
		break;
	case 0x4d:		/* Get Pages for all Handles */
		reg_ah=EMM_GetPagesForAllHandles(SegPhys(es)+reg_di,reg_bx);
		break;
	case 0x4e:		/*Save/Restore Page Map */
		switch (reg_al) {
		case 0x00:	/* Save Page Map */
			MEM_BlockWrite(SegPhys(es)+reg_di,emm_mappings,sizeof(emm_mappings));
			reg_ah=EMM_NO_ERROR;
			break;
		case 0x01:	/* Restore Page Map */
			MEM_BlockRead(SegPhys(ds)+reg_si,emm_mappings,sizeof(emm_mappings));
			reg_ah=EMM_RestoreMappingTable();
			break;
		case 0x02:	/* Save and Restore Page Map */
			MEM_BlockWrite(SegPhys(es)+reg_di,emm_mappings,sizeof(emm_mappings));
			MEM_BlockRead(SegPhys(ds)+reg_si,emm_mappings,sizeof(emm_mappings));
			reg_ah=EMM_RestoreMappingTable();
			break;
		case 0x03:	/* Get Page Map Array Size */
			reg_al=sizeof(emm_mappings);
			reg_ah=EMM_NO_ERROR;
			break;
		default:
			LOG(LOG_MISC,LOG_ERROR)("EMS:Call %2X Subfunction %2X not supported",reg_ah,reg_al);
			reg_ah=EMM_INVALID_SUB;
			break;
		}
		break;
	case 0x4f:	/* Save/Restore Partial Page Map */
		reg_ah=EMM_PartialPageMapping();
		break;
	case 0x50:	/* Map/Unmap multiple handle pages */
		reg_ah = EMM_NO_ERROR;
		switch (reg_al) {
			case 0x00: // use physical page numbers
				{	PhysPt data = SegPhys(ds)+reg_si;
					for (int i=0; i<reg_cx; i++) {
						uint16_t logPage	= mem_readw(data); data+=2;
						uint16_t physPage = mem_readw(data); data+=2;
						reg_ah = EMM_MapPage(physPage,reg_dx,logPage);
						if (reg_ah!=EMM_NO_ERROR) break;
					};
				} break;
			case 0x01: // use segment address
				{	PhysPt data = SegPhys(ds)+reg_si;
					for (int i=0; i<reg_cx; i++) {
						uint16_t logPage	= mem_readw(data); data+=2;
						reg_ah = EMM_MapSegment(mem_readw(data),reg_dx,logPage); data+=2;
						if (reg_ah!=EMM_NO_ERROR) break;
					};
				}
				break;
			default:
				LOG(LOG_MISC,LOG_ERROR)("EMS:Call %2X Subfunction %2X not supported",reg_ah,reg_al);
				reg_ah=EMM_INVALID_SUB;
				break;
		}
		break;
	case 0x51:	/* Reallocate Pages */
		reg_ah=EMM_ReallocatePages(reg_dx,reg_bx);
		break;
	case 0x52: // Set/Get Handle attributes
		reg_ah=GetSetHandleAttributes();
		break;	
	case 0x53: // Set/Get Handlename
		reg_ah=GetSetHandleName();
		break;
	case 0x54:	/* Handle Functions */
		reg_ah=HandleNameSearch();
		break;
	case 0x57:	/* Memory region */
		reg_ah=MemoryRegion();
		if (reg_ah) LOG(LOG_MISC,LOG_ERROR)("EMS:Function 57 move failed");
		break;
	case 0x58: // Get mappable physical array address array
		if (reg_al==0x00) {
			PhysPt data = SegPhys(es)+reg_di;
			uint16_t step = 0x1000 / EMM_MAX_PHYS;
			for (uint16_t i=0; i<EMM_MAX_PHYS; i++) {
				mem_writew(data,EMM_PAGEFRAME+step*i);	data+=2;
				mem_writew(data,i);						data+=2;
			};
		};
		// Set number of pages
		reg_cx = EMM_MAX_PHYS;
		reg_ah = EMM_NO_ERROR;
		break;
	case 0x59: // Get hardware information
		reg_ah=EMM_NO_ERROR;
		switch (reg_al) {
		case 0x00:	// Get hardware configuration
			{
				PhysPt data=SegPhys(es)+reg_di;
				mem_writew(data,0x0400); data+=2;		// 1 page is 1K paragraphs (16KB)
				mem_writew(data,0x0000); data+=2;		// No alternate register sets
				mem_writew(data,sizeof(emm_mappings)); data+=2;	// Context save area size
				mem_writew(data,0x0000); data+=2;		// No DMA channels
				mem_writew(data,0x0000);			// Always 0 for LIM standard
			}
			break;
		case 0x01:	// get unallocated raw page count
			reg_dx=(uint16_t)(MEM_TotalPages()/4);		//Not entirely correct but okay
			reg_bx=EMM_GetFreePages();
			break;
		default:
			LOG(LOG_MISC,LOG_ERROR)("EMS:Call 59 subfct %2X not supported",reg_al);
			reg_ah=EMM_INVALID_SUB;
			break;
		}
		break;
	case 0x5A:              /* Allocate standard/raw Pages */
		if (reg_al<=0x01) {
			reg_ah=EMM_AllocateMemory(reg_bx,reg_dx,true);	// can allocate 0 pages
		} else {
			LOG(LOG_MISC,LOG_ERROR)("EMS:Call 5A subfct %2X not supported",reg_al);
			reg_ah=EMM_INVALID_SUB;
		};
		break;
	case 0xDE:		/* VCPI Functions */
		if (!vcpi.enabled) {
			LOG(LOG_MISC,LOG_ERROR)("EMS:VCPI Call %2X not supported",reg_al);
			reg_ah=EMM_FUNC_NOSUP;
		} else {
			switch (reg_al) {
			case 0x00:		/* VCPI Installation Check */
				if (((reg_cx==0) && (reg_di==0x0012)) || (cpu.pmode && (reg_flags & FLAG_VM))) {
					/* JEMM detected or already in v86 mode */
					reg_ah=EMM_NO_ERROR;
					reg_bx=0x100;
				} else {
					reg_ah=EMM_FUNC_NOSUP;
				}
				break;
			case 0x01: {	/* VCPI Get Protected Mode Interface */
				uint16_t ct;
				/* Set up page table buffer */
				for (ct=0; ct<0xff; ct++) {
					real_writeb(SegValue(es),reg_di+ct*4+0x00,0x67);		// access bits
					real_writew(SegValue(es),reg_di+ct*4+0x01,ct*0x10);		// mapping
					real_writeb(SegValue(es),reg_di+ct*4+0x03,0x00);
				}
				for (ct=0xff; ct<0x100; ct++) {
					real_writeb(SegValue(es),reg_di+ct*4+0x00,0x67);		// access bits
					real_writew(SegValue(es),reg_di+ct*4+0x01,(ct-0xff)*0x10+0x1100);	// mapping
					real_writeb(SegValue(es),reg_di+ct*4+0x03,0x00);
				}
				/* adjust paging entries for page frame (if mapped) */
				for (ct=0; ct<4; ct++) {
					uint16_t handle=emm_mappings[ct].handle;
					if (handle!=0xffff) {
						uint16_t memh=(uint16_t)MEM_NextHandleAt(emm_handles[handle].mem,emm_mappings[ct].page*4);
						uint16_t entry_addr=reg_di+(EMM_PAGEFRAME>>6)+(ct*0x10);
						real_writew(SegValue(es),entry_addr+0x00+0x01,(memh+0)*0x10);		// mapping of 1/4 of page
						real_writew(SegValue(es),entry_addr+0x04+0x01,(memh+1)*0x10);		// mapping of 2/4 of page
						real_writew(SegValue(es),entry_addr+0x08+0x01,(memh+2)*0x10);		// mapping of 3/4 of page
						real_writew(SegValue(es),entry_addr+0x0c+0x01,(memh+3)*0x10);		// mapping of 4/4 of page
					}
				}
				reg_di+=0x400;		// advance pointer by 0x100*4

				/* Set up three descriptor table entries */
				uint32_t cbseg_low=(CALLBACK_GetBase()&0xffff)<<16;
				uint32_t cbseg_high=(CALLBACK_GetBase()&0x1f0000)>>16;
				/* Descriptor 1 (code segment, callback segment) */
				real_writed(SegValue(ds),reg_si+0x00,0x0000ffff|cbseg_low);
				real_writed(SegValue(ds),reg_si+0x04,0x00009a00|cbseg_high);
				/* Descriptor 2 (data segment, full access) */
				real_writed(SegValue(ds),reg_si+0x08,0x0000ffff);
				real_writed(SegValue(ds),reg_si+0x0c,0x00009200);
				/* Descriptor 3 (full access) */
				real_writed(SegValue(ds),reg_si+0x10,0x0000ffff);
				real_writed(SegValue(ds),reg_si+0x14,0x00009200);

				reg_ebx=(vcpi.pm_interface&0xffff);
				reg_ah=EMM_NO_ERROR;
				break;
				}
			case 0x02:		/* VCPI Maximum Physical Address */
				reg_edx=((MEM_TotalPages()*dos_pagesize)-1)&0xfffff000;
				reg_ah=EMM_NO_ERROR;
				break;
			case 0x03:		/* VCPI Get Number of Free Pages */
				reg_edx=MEM_FreeTotal();
				reg_ah=EMM_NO_ERROR;
				break;
			case 0x04: {	/* VCPI Allocate one Page */
				MemHandle mem = MEM_AllocatePages(1,false);
				if (mem) {
					reg_edx=mem<<12;
					reg_ah=EMM_NO_ERROR;
				} else {
					reg_ah=EMM_OUT_OF_LOG;
				}
				break;
				}
			case 0x05:		/* VCPI Free Page */
				MEM_ReleasePages(reg_edx>>12);
				reg_ah=EMM_NO_ERROR;
				break;
			case 0x06: {	/* VCPI Get Physical Address of Page in 1st MB */
				if (((reg_cx<<8)>=EMM_PAGEFRAME) && ((reg_cx<<8)<EMM_PAGEFRAME+0x1000)) {
					/* Page is in Pageframe, so check what EMS-page it is
					   and return the physical address */
					uint8_t phys_page;
					uint16_t mem_seg=reg_cx<<8;
					if (mem_seg<EMM_PAGEFRAME+0x400) phys_page=0;
					else if (mem_seg<EMM_PAGEFRAME+0x800) phys_page=1;
					else if (mem_seg<EMM_PAGEFRAME+0xc00) phys_page=2;
					else phys_page=3;
					uint16_t handle=emm_mappings[phys_page].handle;
					if (handle==0xffff) {
						reg_ah=EMM_ILL_PHYS;
						break;
					} else {
						MemHandle memh=MEM_NextHandleAt(
							emm_handles[handle].mem,
							emm_mappings[phys_page].page*4);
						reg_edx=(memh+(reg_cx&3))<<12;
					}
				} else {
					/* Page not in Pageframe, so just translate into physical address */
					reg_edx=reg_cx<<12;
				}

				reg_ah=EMM_NO_ERROR;
				}
				break;
			case 0x0a:		/* VCPI Get PIC Vector Mappings */
				reg_bx = vcpi.pic1_remapping; // primary PIC
				reg_cx = vcpi.pic2_remapping; // secondary PIC
				reg_ah = EMM_NO_ERROR;
				break;
			case 0x0b:		/* VCPI Set PIC Vector Mappings */
				reg_flags&=(~FLAG_IF);
				vcpi.pic1_remapping=reg_bx&0xff;
				vcpi.pic2_remapping=reg_cx&0xff;
				reg_ah=EMM_NO_ERROR;
				break;
			case 0x0c: {	/* VCPI Switch from V86 to Protected Mode */
				reg_flags&=(~FLAG_IF);
				cpu.cpl=0;

				/* Read data from ESI (linear address) */
				uint32_t new_cr3=mem_readd(reg_esi);
				uint32_t new_gdt_addr=mem_readd(reg_esi+4);
				uint32_t new_idt_addr=mem_readd(reg_esi+8);
				uint16_t new_ldt=mem_readw(reg_esi+0x0c);
				uint16_t new_tr=mem_readw(reg_esi+0x0e);
				uint32_t new_eip=mem_readd(reg_esi+0x10);
				uint16_t new_cs=mem_readw(reg_esi+0x14);

				/* Get GDT and IDT entries */
				uint16_t new_gdt_limit=mem_readw(new_gdt_addr);
				uint32_t new_gdt_base=mem_readd(new_gdt_addr+2);
				uint16_t new_idt_limit=mem_readw(new_idt_addr);
				uint32_t new_idt_base=mem_readd(new_idt_addr+2);

				/* Switch to protected mode, paging enabled if necessary */
				uint32_t new_cr0=CPU_GET_CRX(0)|1;
				if (new_cr3!=0) new_cr0|=0x80000000;
				CPU_SET_CRX(0, new_cr0);
				CPU_SET_CRX(3, new_cr3);

				PhysPt tbaddr=new_gdt_base+(new_tr&0xfff8)+5;
				uint8_t tb=mem_readb(tbaddr);
				mem_writeb(tbaddr, tb&0xfd);

				/* Load tables and initialize segment registers */
				CPU_LGDT(new_gdt_limit, new_gdt_base);
				CPU_LIDT(new_idt_limit, new_idt_base);
				if (CPU_LLDT(new_ldt)) LOG_MSG("VCPI: Could not load LDT with %x",new_ldt);
				if (CPU_LTR(new_tr)) LOG_MSG("VCPI: Could not load TR with %x",new_tr);

				CPU_SetSegGeneral(ds,0);
				CPU_SetSegGeneral(es,0);
				CPU_SetSegGeneral(fs,0);
				CPU_SetSegGeneral(gs,0);

//				MEM_A20_Enable(true);

				/* Switch to protected mode */
				reg_flags&=(~(FLAG_VM|FLAG_NT));
				reg_flags|=0x3000;
				CPU_JMP(true, new_cs, new_eip, 0);
				}
				break;
			default:
				LOG(LOG_MISC,LOG_ERROR)("EMS:VCPI Call %x not supported",reg_ax);
				reg_ah=EMM_FUNC_NOSUP;
				break;
			}
		}
		break;
	default:
		LOG(LOG_MISC,LOG_ERROR)("EMS:Call %2X not supported",reg_ah);
		reg_ah=EMM_FUNC_NOSUP;
		break;
	}
	return CBRET_NONE;
}

static Bitu VCPI_PM_Handler() {
//	LOG_MSG("VCPI PMODE handler, function %x",reg_ax);
	switch (reg_ax) {
	case 0xDE03:		/* VCPI Get Number of Free Pages */
		reg_edx=MEM_FreeTotal();
		reg_ah=EMM_NO_ERROR;
		break;
	case 0xDE04: {		/* VCPI Allocate one Page */
		MemHandle mem = MEM_AllocatePages(1,false);
		if (mem) {
			reg_edx=mem<<12;
			reg_ah=EMM_NO_ERROR;
		} else {
			reg_ah=EMM_OUT_OF_LOG;
		}
		break;
		}
	case 0xDE05:		/* VCPI Free Page */
		MEM_ReleasePages(reg_edx>>12);
		reg_ah=EMM_NO_ERROR;
		break;
	case 0xDE0C: {		/* VCPI Switch from Protected Mode to V86 */
		reg_flags&=(~FLAG_IF);

		/* Flags need to be filled in, VM=true, IOPL=3 */
		mem_writed(SegPhys(ss) + (reg_esp & cpu.stack.mask)+0x10, 0x23002);

		/* Disable Paging */
		CPU_SET_CRX(0, CPU_GET_CRX(0)&0x7ffffff7);
		CPU_SET_CRX(3, 0);

		PhysPt tbaddr=vcpi.private_area+0x0000+(0x10&0xfff8)+5;
		uint8_t tb=mem_readb(tbaddr);
		mem_writeb(tbaddr, tb&0xfd);

		/* Load descriptor table registers */
		CPU_LGDT(0xff, vcpi.private_area+0x0000);
		CPU_LIDT(0x7ff, vcpi.private_area+0x2000);
		if (CPU_LLDT(0x08)) LOG_MSG("VCPI: Could not load LDT");
		if (CPU_LTR(0x10)) LOG_MSG("VCPI: Could not load TR");

		reg_flags&=(~FLAG_NT);
		reg_esp+=8;		// skip interrupt return information
//		MEM_A20_Enable(false);

		/* Switch to v86-task */
		CPU_IRET(true,0);
		}
		break;
	default:
		LOG(LOG_MISC,LOG_WARN)("Unhandled VCPI-function %x in protected mode",reg_al);
		break;
	}
	return CBRET_NONE;
}

static Bitu V86_Monitor() {
	/* Calculate which interrupt did occur */
	Bitu int_num=(mem_readw(SegPhys(ss)+(reg_esp & cpu.stack.mask))-0x2803);

	/* See if Exception 0x0d and not Interrupt 0x0d */
	if ((int_num==(0x0d*4)) && ((reg_sp&0xffff)!=0x1fda)) {
		/* Protection violation during V86-execution,
		   needs intervention by monitor (depends on faulting opcode) */

		reg_esp+=6;		// skip ip of CALL and error code of EXCEPTION 0x0d

		/* Get address of faulting instruction */
		uint16_t v86_cs=mem_readw(SegPhys(ss)+((reg_esp+4) & cpu.stack.mask));
		uint16_t v86_ip=mem_readw(SegPhys(ss)+((reg_esp+0) & cpu.stack.mask));
		uint8_t v86_opcode=mem_readb((v86_cs<<4)+v86_ip);
//		LOG_MSG("v86 monitor caught protection violation at %x:%x, opcode=%x",v86_cs,v86_ip,v86_opcode);
		switch (v86_opcode) {
			case 0x0f:		// double byte opcode
				v86_opcode=mem_readb((v86_cs<<4)+v86_ip+1);
				switch (v86_opcode) {
					case 0x20: {	// mov reg,CRx
						Bitu rm_val=mem_readb((v86_cs<<4)+v86_ip+2);
						Bitu which=(rm_val >> 3) & 7;
						if ((rm_val<0xc0) || (rm_val>=0xe8))
							E_Exit("Invalid opcode 0x0f 0x20 %x caused a protection fault!",static_cast<unsigned int>(rm_val));
						uint32_t crx=CPU_GET_CRX(which);
						switch (rm_val&7) {
							case 0:	reg_eax=crx;	break;
							case 1:	reg_ecx=crx;	break;
							case 2:	reg_edx=crx;	break;
							case 3:	reg_ebx=crx;	break;
							case 4:	reg_esp=crx;	break;
							case 5:	reg_ebp=crx;	break;
							case 6:	reg_esi=crx;	break;
							case 7:	reg_edi=crx;	break;
						}
						mem_writew(SegPhys(ss)+((reg_esp+0) & cpu.stack.mask),v86_ip+3);
						}
						break;
					case 0x22: {	// mov CRx,reg
						Bitu rm_val=mem_readb((v86_cs<<4)+v86_ip+2);
						Bitu which=(rm_val >> 3) & 7;
						if ((rm_val<0xc0) || (rm_val>=0xe8))
							E_Exit("Invalid opcode 0x0f 0x22 %x caused a protection fault!",static_cast<unsigned int>(rm_val));
						uint32_t crx=0;
						switch (rm_val&7) {
							case 0:	crx=reg_eax;	break;
							case 1:	crx=reg_ecx;	break;
							case 2:	crx=reg_edx;	break;
							case 3:	crx=reg_ebx;	break;
							case 4:	crx=reg_esp;	break;
							case 5:	crx=reg_ebp;	break;
							case 6:	crx=reg_esi;	break;
							case 7:	crx=reg_edi;	break;
						}
						if (which==0) crx|=1;	// protection bit always on
						CPU_SET_CRX(which,crx);
						mem_writew(SegPhys(ss)+((reg_esp+0) & cpu.stack.mask),v86_ip+3);
						}
						break;
					default:
						E_Exit("Unhandled opcode 0x0f %x caused a protection fault!",v86_opcode);
				}
				break;
			case 0xe4:		// IN AL,Ib
				reg_al=(uint8_t)(IO_ReadB(mem_readb((v86_cs<<4)+v86_ip+1))&0xff);
				mem_writew(SegPhys(ss)+((reg_esp+0) & cpu.stack.mask),v86_ip+2);
				break;
			case 0xe5:		// IN AX,Ib
				reg_ax=(uint16_t)(IO_ReadW(mem_readb((v86_cs<<4)+v86_ip+1))&0xffff);
				mem_writew(SegPhys(ss)+((reg_esp+0) & cpu.stack.mask),v86_ip+2);
				break;
			case 0xe6:		// OUT Ib,AL
				IO_WriteB(mem_readb((v86_cs<<4)+v86_ip+1),reg_al);
				mem_writew(SegPhys(ss)+((reg_esp+0) & cpu.stack.mask),v86_ip+2);
				break;
			case 0xe7:		// OUT Ib,AX
				IO_WriteW(mem_readb((v86_cs<<4)+v86_ip+1),reg_ax);
				mem_writew(SegPhys(ss)+((reg_esp+0) & cpu.stack.mask),v86_ip+2);
				break;
			case 0xec:		// IN AL,DX
				reg_al=(uint8_t)(IO_ReadB(reg_dx)&0xff);
				mem_writew(SegPhys(ss)+((reg_esp+0) & cpu.stack.mask),v86_ip+1);
				break;
			case 0xed:		// IN AX,DX
				reg_ax=(uint16_t)(IO_ReadW(reg_dx)&0xffff);
				mem_writew(SegPhys(ss)+((reg_esp+0) & cpu.stack.mask),v86_ip+1);
				break;
			case 0xee:		// OUT DX,AL
				IO_WriteB(reg_dx,reg_al);
				mem_writew(SegPhys(ss)+((reg_esp+0) & cpu.stack.mask),v86_ip+1);
				break;
			case 0xef:		// OUT DX,AX
				IO_WriteW(reg_dx,reg_ax);
				mem_writew(SegPhys(ss)+((reg_esp+0) & cpu.stack.mask),v86_ip+1);
				break;
			case 0xf0:		// LOCK prefix
				mem_writew(SegPhys(ss)+((reg_esp+0) & cpu.stack.mask),v86_ip+1);
				break;
			case 0xf4:		// HLT
				reg_flags|=FLAG_IF;
				CPU_HLT(reg_eip);
				mem_writew(SegPhys(ss)+((reg_esp+0) & cpu.stack.mask),v86_ip+1);
				break;
			default:
				E_Exit("Unhandled opcode %x caused a protection fault!",v86_opcode);
		}
		return CBRET_NONE;
	}

	/* Get address to interrupt handler */
	uint16_t vint_vector_seg=mem_readw(SegValue(ds)+int_num+2);
	uint16_t vint_vector_ofs=mem_readw(int_num);
	if (reg_sp!=0x1fda) reg_esp+=(2+3*4);	// Interrupt from within protected mode
	else reg_esp+=2;

	/* Read entries that were pushed onto the stack by the interrupt */
	uint16_t return_ip=mem_readw(SegPhys(ss)+(reg_esp & cpu.stack.mask));
	uint16_t return_cs=mem_readw(SegPhys(ss)+((reg_esp+4) & cpu.stack.mask));
	uint32_t return_eflags=mem_readd(SegPhys(ss)+((reg_esp+8) & cpu.stack.mask));

	/* Modify stack to call v86-interrupt handler */
	mem_writed(SegPhys(ss)+(reg_esp & cpu.stack.mask),vint_vector_ofs);
	mem_writed(SegPhys(ss)+((reg_esp+4) & cpu.stack.mask),vint_vector_seg);
	mem_writed(SegPhys(ss)+((reg_esp+8) & cpu.stack.mask),return_eflags&(~(FLAG_IF|FLAG_TF)));

	/* Adjust SP of v86-stack */
	uint16_t v86_ss=mem_readw(SegPhys(ss)+((reg_esp+0x10) & cpu.stack.mask));
	uint16_t v86_sp=mem_readw(SegPhys(ss)+((reg_esp+0x0c) & cpu.stack.mask))-6;
	mem_writew(SegPhys(ss)+((reg_esp+0x0c) & cpu.stack.mask),v86_sp);

	/* Return to original code after v86-interrupt handler */
	mem_writew((v86_ss<<4)+v86_sp+0,return_ip);
	mem_writew((v86_ss<<4)+v86_sp+2,return_cs);
	mem_writew((v86_ss<<4)+v86_sp+4,(uint16_t)(return_eflags&0xffff));
	return CBRET_NONE;
}

static void SetupVCPI()
{
	vcpi.ems_handle = 0; // use EMM system handle for VCPI data
	vcpi.enabled    = true;

	vcpi.pic1_remapping = 0x08; // primary PIC base
	vcpi.pic2_remapping = 0x70; // secondary PIC base

	vcpi.private_area=emm_handles[vcpi.ems_handle].mem<<12;

	/* GDT */
	mem_writed(vcpi.private_area+0x0000,0x00000000);	// descriptor 0
	mem_writed(vcpi.private_area+0x0004,0x00000000);	// descriptor 0

	uint32_t ldt_address=(vcpi.private_area+0x1000);
	uint16_t ldt_limit=0xff;
	uint32_t ldt_desc_part=((ldt_address&0xffff)<<16)|ldt_limit;
	mem_writed(vcpi.private_area+0x0008,ldt_desc_part);	// descriptor 1 (LDT)
	ldt_desc_part=((ldt_address&0xff0000)>>16)|(ldt_address&0xff000000)|0x8200;
	mem_writed(vcpi.private_area+0x000c,ldt_desc_part);	// descriptor 1

	uint32_t tss_address=(vcpi.private_area+0x3000);
	uint32_t tss_desc_part=((tss_address&0xffff)<<16)|(0x0068+0x200);
	mem_writed(vcpi.private_area+0x0010,tss_desc_part);	// descriptor 2 (TSS)
	tss_desc_part=((tss_address&0xff0000)>>16)|(tss_address&0xff000000)|0x8900;
	mem_writed(vcpi.private_area+0x0014,tss_desc_part);	// descriptor 2

	/* LDT */
	mem_writed(vcpi.private_area+0x1000,0x00000000);	// descriptor 0
	mem_writed(vcpi.private_area+0x1004,0x00000000);	// descriptor 0
	uint32_t cs_desc_part=((vcpi.private_area&0xffff)<<16)|0xffff;
	mem_writed(vcpi.private_area+0x1008,cs_desc_part);	// descriptor 1 (code)
	cs_desc_part=((vcpi.private_area&0xff0000)>>16)|(vcpi.private_area&0xff000000)|0x9a00;
	mem_writed(vcpi.private_area+0x100c,cs_desc_part);	// descriptor 1
	uint32_t ds_desc_part=((vcpi.private_area&0xffff)<<16)|0xffff;
	mem_writed(vcpi.private_area+0x1010,ds_desc_part);	// descriptor 2 (data)
	ds_desc_part=((vcpi.private_area&0xff0000)>>16)|(vcpi.private_area&0xff000000)|0x9200;
	mem_writed(vcpi.private_area+0x1014,ds_desc_part);	// descriptor 2

	/* IDT setup */
	for (uint16_t int_ct=0; int_ct<0x100; int_ct++) {
		/* build a CALL NEAR V86MON, the value of IP pushed by the
			CALL is used to identify the interrupt number */
		mem_writeb(vcpi.private_area+0x2800+int_ct*4+0,0xe8);	// call
		mem_writew(vcpi.private_area+0x2800+int_ct*4+1,0x05fd-(int_ct*4));
		mem_writeb(vcpi.private_area+0x2800+int_ct*4+3,0xcf);	// iret (dummy)

		/* put a Gate-Descriptor into the IDT */
		mem_writed(vcpi.private_area+0x2000+int_ct*8+0,0x000c0000|(0x2800+int_ct*4));
		mem_writed(vcpi.private_area+0x2000+int_ct*8+4,0x0000ee00);
	}

	/* TSS */
	for (Bitu tse_ct=0; tse_ct<0x68+0x200; tse_ct++) {
		/* clear the TSS as most entries are not used here */
		mem_writeb(vcpi.private_area+0x3000,0);
	}
	/* Set up the ring0-stack */
	mem_writed(vcpi.private_area+0x3004,0x00002000);	// esp
	mem_writed(vcpi.private_area+0x3008,0x00000014);	// ss

	mem_writed(vcpi.private_area+0x3066,0x0068);		// io-map base (map follows, all zero)
}

static Bitu INT4B_Handler() {
	switch (reg_ah) {
	case 0x81:
		CALLBACK_SCF(true);
		reg_ax=0x1;
		break;
	default:
		LOG(LOG_MISC,LOG_WARN)("Unhandled interrupt 4B function %x",reg_ah);
		break;
	}
	return CBRET_NONE;
}

Bitu GetEMSType(Section_prop * section) {
	Bitu rtype = 0;
	const std::string ems_pref = section->Get_string("ems");

	const auto ems_pref_has_bool = parse_bool_setting(ems_pref);

	if (ems_pref_has_bool && *ems_pref_has_bool == true) {
		rtype = 1; // mixed mode
	} else if (ems_pref == "emsboard") {
		rtype = 2;
	} else if (ems_pref == "emm386") {
		rtype = 3;
	} else {
		rtype = 0;
	}
	return rtype;
}

class EMS final : public Module_base {
private:
	uint16_t ems_baseseg = 0;
	DOS_Device *emm_device = nullptr;
	RealPt old67_pointer = 0;
	CALLBACK_HandlerObject call_vdma;
	CALLBACK_HandlerObject call_vcpi;
	CALLBACK_HandlerObject call_v86mon;
	callback_number_t call_int67 = 0;

public:
	EMS(Section *configuration)
	        : Module_base(configuration),
	          call_vdma(),
	          call_vcpi(),
	          call_v86mon()
	{
		ems_type=0;

		/* Virtual DMA interrupt callback */
		call_vdma.Install(&INT4B_Handler,CB_IRET,"Int 4b vdma");
		call_vdma.Set_RealVec(0x4b);

		vcpi.enabled=false;
		GEMMIS_seg=0;

		Section_prop * section=static_cast<Section_prop *>(configuration);
		ems_type=GetEMSType(section);
		if (ems_type<=0) return;

		if (machine==MCH_PCJR) {
			ems_type=0;
			LOG_MSG("EMS disabled for PCJr machine");
			return;
		}
		BIOS_ZeroExtendedSize(true);

		ems_baseseg = DOS_GetMemory(2); // We have 32 bytes

		/* Add a little hack so it appears that there is an actual ems device installed */
		const char* emsname = "EMMXXXX0";
		MEM_BlockWrite(PhysicalMake(ems_baseseg, 0xa), emsname,
		               strlen(emsname) + 1);

		call_int67=CALLBACK_Allocate();
		CALLBACK_Setup(call_int67,&INT67_Handler,CB_IRET,PhysicalMake(ems_baseseg,4),"Int 67 ems");
		RealSetVec(0x67,RealMake(ems_baseseg,4),old67_pointer);

		/* Register the ems device */
		//TODO MAYBE put it in the class.
		emm_device = new device_EMM(ems_type!=2);
		DOS_AddDevice(emm_device);

		/* Clear handle and page tables */
		Bitu i;
		for (i=0;i<EMM_MAX_HANDLES;i++) {
			emm_handles[i].mem=0;
			emm_handles[i].pages=NULL_HANDLE;
			memset(&emm_handles[i].name,0,8);
		}
		for (i=0;i<EMM_MAX_PHYS;i++) {
			emm_mappings[i].page=NULL_PAGE;
			emm_mappings[i].handle=NULL_HANDLE;
		}
		for (i=0;i<0x40;i++) {
			emm_segmentmappings[i].page=NULL_PAGE;
			emm_segmentmappings[i].handle=NULL_HANDLE;
		}

		EMM_AllocateSystemHandle(24);	// allocate OS-dedicated handle (ems handle zero, 384kb)

		if (ems_type==3) {
			DMA_SetWrapping(0xffffffff);	// emm386-bug that disables dma wrapping
		}

		if (!ENABLE_VCPI) return;

		if (ems_type!=2) {
			/* Install a callback that handles VCPI-requests in protected mode requests */
			call_vcpi.Install(&VCPI_PM_Handler,CB_IRETD,"VCPI PM");
			vcpi.pm_interface=(call_vcpi.Get_callback())*CB_SIZE;

			/* Initialize private data area and set up descriptor tables */
			SetupVCPI();

			if (!vcpi.enabled) return;

			/* Install v86-callback that handles interrupts occuring
			   in v86 mode, including protection fault exceptions */
			call_v86mon.Install(&V86_Monitor,CB_IRET,"V86 Monitor");

			mem_writeb(vcpi.private_area+0x2e00,(uint8_t)0xFE);       //GRP 4
			mem_writeb(vcpi.private_area+0x2e01,(uint8_t)0x38);       //Extra Callback instruction
			mem_writew(vcpi.private_area+0x2e02,call_v86mon.Get_callback());		//The immediate word
			mem_writeb(vcpi.private_area+0x2e04,(uint8_t)0x66);
			mem_writeb(vcpi.private_area+0x2e05,(uint8_t)0xCF);       //A IRETD Instruction

			/* Testcode only, starts up dosbox in v86-mode */
			if (ENABLE_V86_STARTUP) {
				/* Prepare V86-task */
				CPU_SET_CRX(0, 1);
				CPU_LGDT(0xff, vcpi.private_area+0x0000);
				CPU_LIDT(0x7ff, vcpi.private_area+0x2000);
				if (CPU_LLDT(0x08)) LOG_MSG("VCPI: Could not load LDT");
				if (CPU_LTR(0x10)) LOG_MSG("VCPI: Could not load TR");

				CPU_Push32(SegValue(gs));
				CPU_Push32(SegValue(fs));
				CPU_Push32(SegValue(ds));
				CPU_Push32(SegValue(es));
				CPU_Push32(SegValue(ss));
				CPU_Push32(0x23002);
				CPU_Push32(SegValue(cs));
				CPU_Push32(reg_eip&0xffff);
				/* Switch to V86-mode */
				cpu.cpl=0;
				CPU_IRET(true,0);
			}
		}
	}

	EMS(const EMS &) = delete;            // prevent copying
	EMS &operator=(const EMS &) = delete; // prevent assignment

	~EMS() {
		if (ems_type<=0) return;

		/* Undo Biosclearing */
		BIOS_ZeroExtendedSize(false);

		/* Remove ems device */
		if (emm_device!=nullptr) {
			DOS_DelDevice(emm_device);
			emm_device=nullptr;
		}
		GEMMIS_seg=0;

		/* Remove the emsname and callback hack */
		char buf[32]= { 0 };
		MEM_BlockWrite(PhysicalMake(ems_baseseg,0),buf,32);
		RealSetVec(0x67,old67_pointer);

		/* Release memory allocated to system handle */
		if (emm_handles[EMM_SYSTEM_HANDLE].pages != NULL_HANDLE) {
			MEM_ReleasePages(emm_handles[EMM_SYSTEM_HANDLE].mem);
		}

		/* Clear handle and page tables */
		//TODO

		if ((!ENABLE_VCPI) || (!vcpi.enabled)) return;

		if (cpu.pmode && GETFLAG(VM)) {
			/* Switch back to real mode if in v86-mode */
			CPU_SET_CRX(0, 0);
			CPU_SET_CRX(3, 0);
			reg_flags&=(~(FLAG_IOPL|FLAG_VM));
			CPU_LIDT(0x3ff, 0);
			cpu.cpl=0;
		}
	}
};

static EMS* test;

void EMS_ShutDown(Section* /*sec*/) {
	delete test;
}

void EMS_Init(Section* sec)
{
	assert(sec);

	test = new EMS(sec);

	constexpr auto changeable_at_runtime = true;
	sec->AddDestroyFunction(&EMS_ShutDown, changeable_at_runtime);
}
