#if defined(GC_WIN32_THREADS) || defined(WIN32_THREADS)

#include "private/gc_priv.h"

#if 0
#define STRICT
#include <windows.h>
#endif

#define MAX_THREADS 64

struct thread_entry {
  LONG in_use;
  DWORD id;
  HANDLE handle;
  void *stack;		/* The cold end of the stack.   */
			/* 0 ==> entry not valid.	*/
			/* !in_use ==> stack == 0	*/
  CONTEXT context;
  GC_bool suspended;
};

volatile GC_bool GC_please_stop = FALSE;

volatile struct thread_entry thread_table[MAX_THREADS];

void GC_push_thread_structures GC_PROTO((void))
{
    /* Unlike the other threads implementations, the thread table here	*/
    /* contains no pointers to the collectable heap.  Thus we have	*/
    /* no private structures we need to preserve.			*/
}

void GC_stop_world()
{
  DWORD thread_id = GetCurrentThreadId();
  int i;

  GC_please_stop = TRUE;
  for (i = 0; i < MAX_THREADS; i++)
    if (thread_table[i].stack != 0
	&& thread_table[i].id != thread_id) {
#     ifdef MSWINCE
        /* SuspendThread will fail if thread is running kernel code */
	while (SuspendThread(thread_table[i].handle) == (DWORD)-1)
	  Sleep(10);
#     else
	/* Apparently the Windows 95 GetOpenFileName call creates	*/
	/* a thread that does not properly get cleaned up, and		*/
	/* SuspendThread on its descriptor may provoke a crash.		*/
	/* This reduces the probability of that event, though it still	*/
	/* appears there's a race here.					*/
	DWORD exitCode; 
	if (GetExitCodeThread(thread_table[i].handle,&exitCode) &&
            exitCode != STILL_ACTIVE) {
            thread_table[i].stack = 0;
	    thread_table[i].in_use = FALSE;
	    CloseHandle(thread_table[i].handle);
	    BZERO((void *)(&thread_table[i].context), sizeof(CONTEXT));
	    continue;
	}
	if (SuspendThread(thread_table[i].handle) == (DWORD)-1)
	  ABORT("SuspendThread failed");
#     endif
      thread_table[i].suspended = TRUE;
    }
}

void GC_start_world()
{
  DWORD thread_id = GetCurrentThreadId();
  int i;
  for (i = 0; i < MAX_THREADS; i++)
    if (thread_table[i].stack != 0 && thread_table[i].suspended
	&& thread_table[i].id != thread_id) {
      if (ResumeThread(thread_table[i].handle) == (DWORD)-1)
	ABORT("ResumeThread failed");
      thread_table[i].suspended = FALSE;
    }
  GC_please_stop = FALSE;
}

# ifdef _MSC_VER
#   pragma warning(disable:4715)
# endif
ptr_t GC_current_stackbottom()
{
  DWORD thread_id = GetCurrentThreadId();
  int i;
  for (i = 0; i < MAX_THREADS; i++)
    if (thread_table[i].stack && thread_table[i].id == thread_id)
      return thread_table[i].stack;
  ABORT("no thread table entry for current thread");
}
# ifdef _MSC_VER
#   pragma warning(default:4715)
# endif

# ifdef MSWINCE
    /* The VirtualQuery calls below won't work properly on WinCE, but	*/
    /* since each stack is restricted to an aligned 64K region of	*/
    /* virtual memory we can just take the next lowest multiple of 64K.	*/
#   define GC_get_lo_stack_addr(s) \
        ((ptr_t)(((DWORD)(s) - 1) & 0xFFFF0000))
# else
    static ptr_t GC_get_lo_stack_addr(ptr_t s)
    {
	ptr_t bottom;
	MEMORY_BASIC_INFORMATION info;
	VirtualQuery(s, &info, sizeof(info));
	do {
	    bottom = info.BaseAddress;
	    VirtualQuery(bottom - 1, &info, sizeof(info));
	} while ((info.Protect & PAGE_READWRITE)
		 && !(info.Protect & PAGE_GUARD));
	return(bottom);
    }
# endif

void GC_push_all_stacks()
{
  DWORD thread_id = GetCurrentThreadId();
  int i;
  for (i = 0; i < MAX_THREADS; i++)
    if (thread_table[i].stack) {
      ptr_t bottom = GC_get_lo_stack_addr(thread_table[i].stack);
      if (thread_table[i].id == thread_id)
	GC_push_all_stack((ptr_t)&i, thread_table[i].stack);
      else {
	thread_table[i].context.ContextFlags
			= (CONTEXT_INTEGER|CONTEXT_CONTROL);
	if (!GetThreadContext(thread_table[i].handle,
				/* cast away volatile qualifier */
	    		        (LPCONTEXT)&thread_table[i].context))
	  ABORT("GetThreadContext failed");
#	ifdef I386
	  if (thread_table[i].context.Esp >= (DWORD)thread_table[i].stack
	      || thread_table[i].context.Esp < (DWORD)bottom)
	      ABORT("Thread stack pointer out of range");
	  GC_push_one ((word) thread_table[i].context.Edi);
    	  GC_push_one ((word) thread_table[i].context.Esi);
    	  GC_push_one ((word) thread_table[i].context.Ebp);
    	  GC_push_one ((word) thread_table[i].context.Ebx);
    	  GC_push_one ((word) thread_table[i].context.Edx);
    	  GC_push_one ((word) thread_table[i].context.Ecx);
    	  GC_push_one ((word) thread_table[i].context.Eax);
	  GC_push_all_stack((char *) thread_table[i].context.Esp,
			    thread_table[i].stack);
#       else
#       ifdef ARM32
	  if (thread_table[i].context.Sp >= (DWORD)thread_table[i].stack
	      || thread_table[i].context.Sp < (DWORD)bottom)
	      ABORT("Thread stack pointer out of range");
	  GC_push_one ((word) thread_table[i].context.R0);
	  GC_push_one ((word) thread_table[i].context.R1);
	  GC_push_one ((word) thread_table[i].context.R2);
	  GC_push_one ((word) thread_table[i].context.R3);
	  GC_push_one ((word) thread_table[i].context.R4);
	  GC_push_one ((word) thread_table[i].context.R5);
	  GC_push_one ((word) thread_table[i].context.R6);
	  GC_push_one ((word) thread_table[i].context.R7);
	  GC_push_one ((word) thread_table[i].context.R8);
	  GC_push_one ((word) thread_table[i].context.R9);
	  GC_push_one ((word) thread_table[i].context.R10);
	  GC_push_one ((word) thread_table[i].context.R11);
	  GC_push_one ((word) thread_table[i].context.R12);
	  GC_push_all_stack((char *) thread_table[i].context.Sp,
			    thread_table[i].stack);
#       else
#	ifdef SHx
	  if (thread_table[i].context.R15 >= (DWORD)thread_table[i].stack
	      || thread_table[i].context.R15 < (DWORD)bottom)
	      ABORT("Thread stack pointer out of range");
	  GC_push_one ((word) thread_table[i].context.R0);
	  GC_push_one ((word) thread_table[i].context.R1);
	  GC_push_one ((word) thread_table[i].context.R2);
	  GC_push_one ((word) thread_table[i].context.R3);
	  GC_push_one ((word) thread_table[i].context.R4);
	  GC_push_one ((word) thread_table[i].context.R5);
	  GC_push_one ((word) thread_table[i].context.R6);
	  GC_push_one ((word) thread_table[i].context.R7);
	  GC_push_one ((word) thread_table[i].context.R8);
	  GC_push_one ((word) thread_table[i].context.R9);
	  GC_push_one ((word) thread_table[i].context.R10);
	  GC_push_one ((word) thread_table[i].context.R11);
	  GC_push_one ((word) thread_table[i].context.R12);
	  GC_push_one ((word) thread_table[i].context.R13);
	  GC_push_one ((word) thread_table[i].context.R14);
	  GC_push_all_stack((char *) thread_table[i].context.R15,
			    thread_table[i].stack);
#       else
#	ifdef MIPS
	  if (thread_table[i].context.IntSp >= (DWORD)thread_table[i].stack
	      || thread_table[i].context.IntSp < (DWORD)bottom)
	      ABORT("Thread stack pointer out of range");
	  GC_push_one ((word) thread_table[i].context.IntAt);
	  GC_push_one ((word) thread_table[i].context.IntV0);
	  GC_push_one ((word) thread_table[i].context.IntV1);
	  GC_push_one ((word) thread_table[i].context.IntA0);
	  GC_push_one ((word) thread_table[i].context.IntA1);
	  GC_push_one ((word) thread_table[i].context.IntA2);
	  GC_push_one ((word) thread_table[i].context.IntA3);
	  GC_push_one ((word) thread_table[i].context.IntT0);
	  GC_push_one ((word) thread_table[i].context.IntT1);
	  GC_push_one ((word) thread_table[i].context.IntT2);
	  GC_push_one ((word) thread_table[i].context.IntT3);
	  GC_push_one ((word) thread_table[i].context.IntT4);
	  GC_push_one ((word) thread_table[i].context.IntT5);
	  GC_push_one ((word) thread_table[i].context.IntT6);
	  GC_push_one ((word) thread_table[i].context.IntT7);
	  GC_push_one ((word) thread_table[i].context.IntS0);
	  GC_push_one ((word) thread_table[i].context.IntS1);
	  GC_push_one ((word) thread_table[i].context.IntS2);
	  GC_push_one ((word) thread_table[i].context.IntS3);
	  GC_push_one ((word) thread_table[i].context.IntS4);
	  GC_push_one ((word) thread_table[i].context.IntS5);
	  GC_push_one ((word) thread_table[i].context.IntS6);
	  GC_push_one ((word) thread_table[i].context.IntS7);
	  GC_push_one ((word) thread_table[i].context.IntT8);
	  GC_push_one ((word) thread_table[i].context.IntT9);
	  GC_push_one ((word) thread_table[i].context.IntK0);
	  GC_push_one ((word) thread_table[i].context.IntK1);
	  GC_push_one ((word) thread_table[i].context.IntS8);
	  GC_push_all_stack((char *) thread_table[i].context.IntSp,
			    thread_table[i].stack);
#	else
#	ifdef PPC
	  if (thread_table[i].context.Gpr1 >= (DWORD)thread_table[i].stack
	      || thread_table[i].context.Gpr1 < (DWORD)bottom)
	      ABORT("Thread stack pointer out of range");
	  GC_push_one ((word) thread_table[i].context.Gpr0);
	  /* Gpr1 is stack pointer */
	  /* Gpr2 is global pointer */
	  GC_push_one ((word) thread_table[i].context.Gpr3);
	  GC_push_one ((word) thread_table[i].context.Gpr4);
	  GC_push_one ((word) thread_table[i].context.Gpr5);
	  GC_push_one ((word) thread_table[i].context.Gpr6);
	  GC_push_one ((word) thread_table[i].context.Gpr7);
	  GC_push_one ((word) thread_table[i].context.Gpr8);
	  GC_push_one ((word) thread_table[i].context.Gpr9);
	  GC_push_one ((word) thread_table[i].context.Gpr10);
	  GC_push_one ((word) thread_table[i].context.Gpr11);
	  GC_push_one ((word) thread_table[i].context.Gpr12);
	  /* Gpr13 is reserved for the kernel */
	  GC_push_one ((word) thread_table[i].context.Gpr14);
	  GC_push_one ((word) thread_table[i].context.Gpr15);
	  GC_push_one ((word) thread_table[i].context.Gpr16);
	  GC_push_one ((word) thread_table[i].context.Gpr17);
	  GC_push_one ((word) thread_table[i].context.Gpr18);
	  GC_push_one ((word) thread_table[i].context.Gpr19);
	  GC_push_one ((word) thread_table[i].context.Gpr20);
	  GC_push_one ((word) thread_table[i].context.Gpr21);
	  GC_push_one ((word) thread_table[i].context.Gpr22);
	  GC_push_one ((word) thread_table[i].context.Gpr23);
	  GC_push_one ((word) thread_table[i].context.Gpr24);
	  GC_push_one ((word) thread_table[i].context.Gpr25);
	  GC_push_one ((word) thread_table[i].context.Gpr26);
	  GC_push_one ((word) thread_table[i].context.Gpr27);
	  GC_push_one ((word) thread_table[i].context.Gpr28);
	  GC_push_one ((word) thread_table[i].context.Gpr29);
	  GC_push_one ((word) thread_table[i].context.Gpr30);
	  GC_push_one ((word) thread_table[i].context.Gpr31);
	  GC_push_all_stack((char *) thread_table[i].context.Gpr1,
			    thread_table[i].stack);
#	else
#	ifdef ALPHA
	  if (thread_table[i].context.IntSp >= (DWORD)thread_table[i].stack
	      || thread_table[i].context.IntSp < (DWORD)bottom)
	      ABORT("Thread stack pointer out of range");
	  GC_push_one ((word) thread_table[i].context.IntV0);
	  GC_push_one ((word) thread_table[i].context.IntT0);
	  GC_push_one ((word) thread_table[i].context.IntT1);
	  GC_push_one ((word) thread_table[i].context.IntT2);
	  GC_push_one ((word) thread_table[i].context.IntT3);
	  GC_push_one ((word) thread_table[i].context.IntT4);
	  GC_push_one ((word) thread_table[i].context.IntT5);
	  GC_push_one ((word) thread_table[i].context.IntT6);
	  GC_push_one ((word) thread_table[i].context.IntT7);
	  GC_push_one ((word) thread_table[i].context.IntS0);
	  GC_push_one ((word) thread_table[i].context.IntS1);
	  GC_push_one ((word) thread_table[i].context.IntS2);
	  GC_push_one ((word) thread_table[i].context.IntS3);
	  GC_push_one ((word) thread_table[i].context.IntS4);
	  GC_push_one ((word) thread_table[i].context.IntS5);
	  GC_push_one ((word) thread_table[i].context.IntFp);
	  GC_push_one ((word) thread_table[i].context.IntA0);
	  GC_push_one ((word) thread_table[i].context.IntA1);
	  GC_push_one ((word) thread_table[i].context.IntA2);
	  GC_push_one ((word) thread_table[i].context.IntA3);
	  GC_push_one ((word) thread_table[i].context.IntA4);
	  GC_push_one ((word) thread_table[i].context.IntA5);
	  GC_push_one ((word) thread_table[i].context.IntT8);
	  GC_push_one ((word) thread_table[i].context.IntT9);
	  GC_push_one ((word) thread_table[i].context.IntT10);
	  GC_push_one ((word) thread_table[i].context.IntT11);
	  GC_push_one ((word) thread_table[i].context.IntT12);
	  GC_push_one ((word) thread_table[i].context.IntAt);
	  GC_push_all_stack((char *) thread_table[i].context.IntSp,
			    thread_table[i].stack);
#	else
	      --> architecture not supported
#	endif /* !ALPHA */
#	endif /* !PPC */
#	endif /* !MIPS */
#	endif /* !SHx */
#	endif /* !ARM32 */
#	endif /* !I386 */
      }
    }
}

void GC_get_next_stack(char *start, char **lo, char **hi)
{
    int i;
#   define ADDR_LIMIT (char *)(-1L)
    char * current_min = ADDR_LIMIT;

    for (i = 0; i < MAX_THREADS; i++) {
    	char * s = (char *)thread_table[i].stack;

	if (0 != s && s > start && s < current_min) {
	    current_min = s;
	}
    }
    *hi = current_min;
    if (current_min == ADDR_LIMIT) {
    	*lo = ADDR_LIMIT;
	return;
    }
    *lo = GC_get_lo_stack_addr(current_min);
    if (*lo < start) *lo = start;
}


# ifdef MSWINCE

typedef struct {
    HANDLE child_ready_h, parent_ready_h;
    volatile struct thread_entry * entry;
    LPTHREAD_START_ROUTINE start;
    LPVOID param;
} thread_args;

DWORD WINAPI thread_start(LPVOID arg);

HANDLE WINAPI GC_CreateThread(
    LPSECURITY_ATTRIBUTES lpThreadAttributes, 
    DWORD dwStackSize, LPTHREAD_START_ROUTINE lpStartAddress, 
    LPVOID lpParameter, DWORD dwCreationFlags, LPDWORD lpThreadId )
{
    HANDLE thread_h = NULL;
    HANDLE child_ready_h, parent_ready_h;

    int i;
    thread_args args;

    /* allocate thread slot */
    LOCK();
    for (i = 0; i != MAX_THREADS && thread_table[i].in_use; i++)
	;
    if (i != MAX_THREADS) {
	thread_table[i].in_use = TRUE;
    }
    UNLOCK();

    if (i != MAX_THREADS) {

	/* create unnamed unsignalled events */
	if (child_ready_h = CreateEvent(NULL, FALSE, FALSE, NULL)) {
	    if (parent_ready_h = CreateEvent(NULL, FALSE, FALSE, NULL)) {

		/* set up thread arguments */
		args.child_ready_h = child_ready_h;
		args.parent_ready_h = parent_ready_h;
		args.entry = &thread_table[i];
		args.start = lpStartAddress;
		args.param = lpParameter;

		thread_h = CreateThread(lpThreadAttributes,
					dwStackSize, thread_start,
					&args,
					dwCreationFlags & ~CREATE_SUSPENDED,
					lpThreadId);

		if (thread_h) {

		    /* fill in ID and handle; tell child this is done */
		    thread_table[i].id = *lpThreadId;
		    thread_table[i].handle = thread_h;
		    SetEvent (parent_ready_h);

		    /* wait for child to fill in stack and copy args */
		    WaitForSingleObject (child_ready_h, INFINITE);

		    /* suspend the child if requested */
		    if (dwCreationFlags & CREATE_SUSPENDED)
			SuspendThread (thread_h);

		    /* let child call given function now (or when resumed) */
		    SetEvent (parent_ready_h);

		} else {
		    CloseHandle (parent_ready_h);
		}
	    }
	}

	CloseHandle (child_ready_h);

	if (thread_h == NULL)
	    thread_table[i].in_use = FALSE;

    } else { /* no thread slot found */
	SetLastError (ERROR_TOO_MANY_TCBS);
    }

    return thread_h;
}

static DWORD WINAPI thread_start(LPVOID arg)
{
    DWORD ret = 0;
    thread_args args = *(thread_args *)arg;

    /* wait for parent to fill in ID and handle */
    WaitForSingleObject (args.parent_ready_h, INFINITE);
    ResetEvent (args.parent_ready_h);

    /* fill in stack; tell parent this is done */
    args.entry->stack = GC_get_stack_base();
    SetEvent (args.child_ready_h);

    /* wait for parent to tell us to go (in case it needs to suspend us) */
    WaitForSingleObject (args.parent_ready_h, INFINITE);
    CloseHandle (args.parent_ready_h);

    /* Clear the thread entry even if we exit with an exception.	*/
    /* This is probably pointless, since an uncaught exception is	*/
    /* supposed to result in the process being killed.			*/
    __try {
	ret = args.start (args.param);
    } __finally {
	LOCK();
	args.entry->stack = 0;
	args.entry->in_use = FALSE;
	      /* cast away volatile qualifier */
	BZERO((void *) &args.entry->context, sizeof(CONTEXT));
	UNLOCK();
    }

    return ret;
}

typedef struct {
    HINSTANCE hInstance;
    HINSTANCE hPrevInstance;
    LPWSTR lpCmdLine;
    int nShowCmd;
} main_thread_args;

DWORD WINAPI main_thread_start(LPVOID arg);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
		   LPWSTR lpCmdLine, int nShowCmd)
{
    DWORD exit_code = 1;

    main_thread_args args = {
	hInstance, hPrevInstance, lpCmdLine, nShowCmd
    };
    HANDLE thread_h;
    DWORD thread_id;

    /* initialize everything */
    InitializeCriticalSection(&GC_allocate_ml);
    GC_init();

    /* start the main thread */
    thread_h = GC_CreateThread(
	NULL, 0, main_thread_start, &args, 0, &thread_id);

    if (thread_h != NULL)
    {
	WaitForSingleObject (thread_h, INFINITE);
	GetExitCodeThread (thread_h, &exit_code);
	CloseHandle (thread_h);
    }

    GC_deinit();
    DeleteCriticalSection(&GC_allocate_ml);

    return (int) exit_code;
}

DWORD WINAPI main_thread_start(LPVOID arg)
{
    main_thread_args * args = (main_thread_args *) arg;

    return (DWORD) GC_WinMain (args->hInstance, args->hPrevInstance,
			       args->lpCmdLine, args->nShowCmd);
}

# else /* !MSWINCE */

LONG WINAPI GC_write_fault_handler(struct _EXCEPTION_POINTERS *exc_info);

/*
 * This isn't generally safe, since DllMain is not premptible.
 * If another thread holds the lock while this runs we're in trouble.
 * Pontus Rydin suggests wrapping the thread start routine instead.
 */
BOOL WINAPI DllMain(HINSTANCE inst, ULONG reason, LPVOID reserved)
{
  switch (reason) {
  case DLL_PROCESS_ATTACH:
    InitializeCriticalSection(&GC_allocate_ml);
    GC_init();	/* Force initialization before thread attach.	*/
    /* fall through */
  case DLL_THREAD_ATTACH:
    {
      int i;
      /* It appears to be unsafe to acquire a lock here, since this	*/
      /* code is apparently not preeemptible on some systems.		*/
      /* (This is based on complaints, not on Microsoft's official	*/
      /* documentation, which says this should perform "only simple	*/
      /* inititalization tasks".)					*/
      /* Hence we make do with nonblocking synchronization.		*/

      /* The following should be a noop according to the win32	*/
      /* documentation.  There is empirical evidence that it	*/
      /* isn't.		- HB					*/
#     ifdef MPROTECT_VDB
       if (GC_incremental) SetUnhandledExceptionFilter(GC_write_fault_handler);
#     endif

      for (i = 0;
			       /* cast away volatile qualifier */
	   InterlockedExchange((LPLONG) &thread_table[i].in_use, 1) != 0;
	   i++) {
	/* Compare-and-swap would make this cleaner, but that's not 	*/
	/* supported before Windows 98 and NT 4.0.  In Windows 2000,	*/
	/* InterlockedExchange is supposed to be replaced by		*/
	/* InterlockedExchangePointer, but that's not really what I	*/
	/* want here.							*/
	if (i == MAX_THREADS - 1)
	  ABORT("too many threads");
      }
      thread_table[i].id = GetCurrentThreadId();
      if (!DuplicateHandle(GetCurrentProcess(),
			   GetCurrentThread(),
			   GetCurrentProcess(),
			   /* cast away volatile qualifier */
			   (HANDLE *) &thread_table[i].handle,
			   0,
			   0,
			   DUPLICATE_SAME_ACCESS)) {
	DWORD last_error = GetLastError();
	GC_printf1("Last error code: %lx\n", last_error);
	ABORT("DuplicateHandle failed");
      }
      thread_table[i].stack = GC_get_stack_base();
      /* If this thread is being created while we are trying to stop	*/
      /* the world, wait here.  Hopefully this can't happen on any	*/
      /* systems that don't allow us to block here.			*/
      while (GC_please_stop) Sleep(20);
    }
    break;
  case DLL_THREAD_DETACH:
    {
      int i;
      DWORD thread_id = GetCurrentThreadId();
      LOCK();
      for (i = 0;
           i < MAX_THREADS &&
	   (thread_table[i].stack == 0 || thread_table[i].id != thread_id);
	   i++) {}
      if (i >= MAX_THREADS) {
	  WARN("thread %ld not found on detach", (GC_word)thread_id);
      } else {
          thread_table[i].stack = 0;
          thread_table[i].in_use = FALSE;
          CloseHandle(thread_table[i].handle);
	    /* cast away volatile qualifier */
          BZERO((void *) &thread_table[i].context, sizeof(CONTEXT));
      }
      UNLOCK();
    }
    break;
  case DLL_PROCESS_DETACH:
    {
      int i;

      LOCK();
      for (i = 0; i < MAX_THREADS; ++i)
      {
          if (thread_table[i].in_use)
          {
              thread_table[i].stack = 0;
              thread_table[i].in_use = FALSE;
              CloseHandle(thread_table[i].handle);
              BZERO((void *) &thread_table[i].context, sizeof(CONTEXT));
          }
      }
      UNLOCK();

      GC_deinit();
      DeleteCriticalSection(&GC_allocate_ml);
    }
    break;

  }
  return TRUE;
}

# endif /* !MSWINCE */

#endif /* WIN32_THREADS */