/*  GRT stack implementation for Win32 using fibers.
    Copyright (C) 2005 - 2014 Tristan Gingold.

    GHDL 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, or (at your option) any later
    version.

    GHDL 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 GCC; see the file COPYING.  If not, write to the Free
    Software Foundation, 59 Temple Place - Suite 330, Boston, MA
    02111-1307, USA.

    As a special exception, if other files instantiate generics from this
    unit, or you link this unit with other files to produce an executable,
    this unit does not by itself cause the resulting executable to be
    covered by the GNU General Public License. This exception does not
    however invalidate any other reasons why the executable file might be
    covered by the GNU Public License.
*/

#include <windows.h>
#include <stdio.h>
#include <setjmp.h>
#include <assert.h>
#include <excpt.h>

static EXCEPTION_DISPOSITION
ghdl_SEH_handler (struct _EXCEPTION_RECORD* ExceptionRecord,
		  void *EstablisherFrame,
		  struct _CONTEXT* ContextRecord,
		  void *DispatcherContext);

struct exception_registration
{
  struct exception_registration *prev;
  void *handler;
};

struct stack_type
{
  LPVOID fiber; //  Win fiber.
  void (*func)(void *);  // Function
  void *arg; //  Function argument.
};

static struct stack_type main_stack_context;
static struct stack_type *current;
extern void grt_set_main_stack (struct stack_type *stack);

void grt_stack_init(void)
{
  main_stack_context.fiber = ConvertThreadToFiber (NULL);
  if (main_stack_context.fiber == NULL)
    {
      fprintf (stderr, "convertThreadToFiber failed (err=%lu)\n",
	       GetLastError ());
      abort ();
    }
  grt_set_main_stack (&main_stack_context);
  current = &main_stack_context;
}

static VOID __stdcall
grt_stack_loop (void *v_stack)
{
  struct stack_type *stack = (struct stack_type *)v_stack;
  struct exception_registration er;
  struct exception_registration *prev;

  /* Get current handler.  */
  asm ("mov %%fs:(0),%0" : "=r" (prev));

  /* Build regisration.  */
  er.prev = prev;
  er.handler = ghdl_SEH_handler;

  /* Register.  */
  asm ("mov %0,%%fs:(0)" : : "r" (&er));

  while (1)
    {
      (*stack->func)(stack->arg);
    }
}

struct stack_type *
grt_stack_create (void (*func)(void *), void *arg) 
{
  struct stack_type *res;

  res = malloc (sizeof (struct stack_type));
  if (res == NULL)
    return NULL;
  res->func = func;
  res->arg = arg;
  res->fiber = CreateFiber (0, &grt_stack_loop, res);
  if (res->fiber == NULL)
    {
      free (res);
      return NULL;
    }
  return res;
}

static int run_env_en;
static jmp_buf run_env;
static int need_longjmp;

void
grt_stack_switch (struct stack_type *to, struct stack_type *from)
{
  assert (current == from);
  current = to;
  SwitchToFiber (to->fiber);
  if (from == &main_stack_context && need_longjmp)
    {
      /* We returned to do the longjump.  */
      current = &main_stack_context;
      longjmp (run_env, need_longjmp);
    }
}

void
grt_stack_delete (struct stack_type *stack)
{
  DeleteFiber (stack->fiber);
  stack->fiber = NULL;
}

void
__ghdl_maybe_return_via_longjump (int val)
{
  if (!run_env_en)
    return;

  if (current != &main_stack_context)
    {
      /* We are allowed to jump only in the same stack.
	 First switch back to the main thread.  */
      need_longjmp = val;
      SwitchToFiber (main_stack_context.fiber);
    }
  else
    longjmp (run_env, val);
}

extern void grt_stack_error_grow_failed (void);
extern void grt_stack_error_null_access (void);
extern void grt_stack_error_memory_access (void);
extern void grt_overflow_error (void);

static EXCEPTION_DISPOSITION
ghdl_SEH_handler (struct _EXCEPTION_RECORD* ExceptionRecord,
		  void *EstablisherFrame,
		  struct _CONTEXT* ContextRecord,
		  void *DispatcherContext)
{
  const char *msg = "";

  switch (ExceptionRecord->ExceptionCode)
    {
    case EXCEPTION_ACCESS_VIOLATION:
      if (ExceptionRecord->ExceptionInformation[1] == 0)
	grt_stack_error_null_access ();
      else
	grt_stack_error_memory_access ();
      break;
          
    case EXCEPTION_FLT_DENORMAL_OPERAND:
    case EXCEPTION_FLT_DIVIDE_BY_ZERO:
    case EXCEPTION_FLT_INVALID_OPERATION:
    case EXCEPTION_FLT_OVERFLOW:
    case EXCEPTION_FLT_STACK_CHECK:
    case EXCEPTION_FLT_UNDERFLOW:
      msg = "floating point error";
      break;
     
    case EXCEPTION_INT_DIVIDE_BY_ZERO:
      msg = "division by 0";
      break;
     
    case EXCEPTION_INT_OVERFLOW:
      grt_overflow_error ();
      break;
           
    case EXCEPTION_STACK_OVERFLOW:
      msg = "stack overflow";
      break;
     
    default:
      msg = "unknown reason";
      break;
    }

  /* FIXME: is it correct?  */
  fprintf (stderr, "exception raised: %s\n", msg);

  __ghdl_maybe_return_via_longjump (1);
  return 0; /* This is never reached, avoid compiler warning  */
}

int
__ghdl_run_through_longjump (int (*func)(void))
{
  int res;
  struct exception_registration er;
  struct exception_registration *prev;

  /* Get current handler.  */
  asm ("mov %%fs:(0),%0" : "=r" (prev));

  /* Build regisration.  */
  er.prev = prev;
  er.handler = ghdl_SEH_handler;

  /* Register.  */
  asm ("mov %0,%%fs:(0)" : : "r" (&er));

  run_env_en = 1;
  res = setjmp (run_env);
  if (res == 0)
    res = (*func)();
  run_env_en = 0;

  /* Restore.  */
  asm ("mov %0,%%fs:(0)" : : "r" (prev));

  return res;
}

#include <math.h>

double acosh (double x)
{
  return log (x + sqrt (x*x - 1));
}

double asinh (double x)
{
  return log (x + sqrt (x*x + 1));
}

double atanh (double x)
{
  return log ((1 + x) / (1 - x)) / 2;
}

#ifndef WITH_GNAT_RUN_TIME
void __gnat_raise_storage_error(void)
{
   abort ();
}

void __gnat_raise_program_error(void)
{
   abort ();
}
#endif