/*
Copyright (C) 1996-1997 Id Software, Inc.

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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/
#include <sys/segments.h>
#include <go32.h>
#include <sys/nearptr.h>
#include <dos.h>
#include <string.h>
#include <dpmi.h>
// #include <osfcn.h>
#include <bios.h>

#include "dosisms.h"
#include <quakedef.h>

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

_go32_dpmi_registers hmm;

// globals
regs_t regs;
void (*dos_error_func)(char *msg, ...);

static unsigned conventional_memory = -1;

__dpmi_regs callback_regs;

void
map_in_conventional_memory ( void )
{
	if (conventional_memory == -1)
	{
		if (__djgpp_nearptr_enable())
		{
			conventional_memory = __djgpp_conventional_base;
		}
	}
}

unsigned int
ptr2real ( void *ptr )
{
	map_in_conventional_memory();
	return (int)ptr - conventional_memory;
}

void *
real2ptr ( unsigned int real )
{
	map_in_conventional_memory();
	return (void *) (real + conventional_memory);
}

void *
far2ptr( unsigned int farptr )
{
	return real2ptr(((farptr & ~0xffff) >>12) + (farptr&0xffff));
}

unsigned int
ptr2far ( void *ptr )
{
	return ((ptr2real(ptr)&~0xf) << 12) + (ptr2real(ptr) & 0xf);
}

int
dos_inportb ( int port )
{
	return inportb(port);
}

int
dos_inportw ( int port )
{
	return inportw(port);
}

void
dos_outportb ( int port, int val )
{
	outportb(port, val);
}

void
dos_outportw ( int port, int val )
{
	outportw(port, val);
}

void
dos_irqenable ( void )
{
	enable();
}

void
dos_irqdisable ( void )
{
	disable();
}

//
// Returns 0 on success
//

int
dos_int86 ( int vec )
{
	int rc;
	regs.x.ss = regs.x.sp = 0;
	rc = _go32_dpmi_simulate_int(vec, (_go32_dpmi_registers *) &regs);
	return rc || (regs.x.flags & 1);
}

int
dos_int386 ( int vec, regs_t *inregs, regs_t *outregs )
{
	int rc;
	memcpy(outregs, inregs, sizeof(regs_t));
	outregs->x.ss = outregs->x.sp = 0;
	rc = _go32_dpmi_simulate_int(vec, (_go32_dpmi_registers *) outregs);
	return rc || (outregs->x.flags & 1);
}

//
// Because of a quirk in dj's alloc-dos-memory wrapper, you need to keep
// the seginfo structure around for when you free the mem.
//

static _go32_dpmi_seginfo seginfo[10];

void *
dos_getmemory ( int size )
{
	int rc;
	_go32_dpmi_seginfo info;
	static int firsttime=1;
	int i;

	if (firsttime)
	{
		memset(seginfo, 0, sizeof(seginfo));
		firsttime = 0;
	}

	info.size = (size+15) / 16;
	rc = _go32_dpmi_allocate_dos_memory(&info);
	if (rc)
		return 0;

	for (i=0;i<10;i++)
		if (!seginfo[i].rm_segment) break;
	seginfo[i] = info;
	return real2ptr((int) info.rm_segment << 4);

}

void
dos_freememory ( void *ptr )
{
	int i;
	int segment;

	segment = ptr2real(ptr) >> 4;
	for (i=0 ; i<10 ; i++)
		if (seginfo[i].rm_segment == segment)
		{
			_go32_dpmi_free_dos_memory(&seginfo[i]);
			seginfo[i].rm_segment = 0;
			break;
		}

}

static struct handlerhistory_s
{
	int intr;
	_go32_dpmi_seginfo pm_oldvec;
} handlerhistory[4];

static int handlercount=0;

void
dos_registerintr ( int intr, void (*handler)(void) )
{
	_go32_dpmi_seginfo info;
	struct handlerhistory_s *oldstuff;

	oldstuff = &handlerhistory[handlercount];

// remember old handler
	_go32_dpmi_get_protected_mode_interrupt_vector(intr, &oldstuff->pm_oldvec);
	oldstuff->intr = intr;

	info.pm_offset = (int) handler;
	_go32_dpmi_allocate_iret_wrapper(&info);

// set new protected mode handler
	_go32_dpmi_set_protected_mode_interrupt_vector(intr, &info);

	handlercount++;

}

void
dos_restoreintr ( int intr )
{
	int i;
	struct handlerhistory_s *oldstuff;

// find and reinstall previous interrupt
	for (i=0 ; i<handlercount ; i++)
	{
		oldstuff = &handlerhistory[i];
		if (oldstuff->intr == intr)
		{
			_go32_dpmi_set_protected_mode_interrupt_vector(intr,
				&oldstuff->pm_oldvec);
			oldstuff->intr = -1;
			break;
		}
	}

}

void
dos_usleep ( int usecs )
{
	usleep ( usecs );
}

int
dos_getheapsize ( void )
{
	return _go32_dpmi_remaining_physical_memory();
}

int
dos_lockmem ( void *addr, int size )
{
	__dpmi_meminfo info;
	info.address = (long) addr + __djgpp_base_address;
	info.size = size;
	if (__dpmi_lock_linear_region(&info))
		return __dpmi_error;
	else
		return 0;
}

int
dos_unlockmem ( void *addr, int size )
{
	__dpmi_meminfo info;
	info.address = (long) addr + __djgpp_base_address;
	info.size = size;
	if (__dpmi_unlock_linear_region(&info))
		return __dpmi_error;
	else
		return 0;
}