/*
	dos_v2.c

	@description@

	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:

		Free Software Foundation, Inc.
		59 Temple Place - Suite 330
		Boston, MA  02111-1307, USA

	$Id$
*/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif

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

#include "dosisms.h"

_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;
}