/*
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 <unistd.h>
#include <sys/nearptr.h>
#include <dos.h>
#include <string.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;
}