// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

#include <errno.h>
#include <signal.h>

#include "runtime.h"
#include "go-assert.h"

/* For targets which don't have the required sync support.  Really
   these should be provided by gcc itself.  FIXME.  */

#if !defined (HAVE_SYNC_BOOL_COMPARE_AND_SWAP_4) || !defined (HAVE_SYNC_FETCH_AND_ADD_4)

static pthread_mutex_t sync_lock = PTHREAD_MUTEX_INITIALIZER;

#endif

#ifndef HAVE_SYNC_BOOL_COMPARE_AND_SWAP_4

_Bool
__sync_bool_compare_and_swap_4 (uint32*, uint32, uint32)
  __attribute__ ((visibility ("hidden")));

_Bool
__sync_bool_compare_and_swap_4 (uint32* ptr, uint32 old, uint32 new)
{
  int i;
  _Bool ret;

  i = pthread_mutex_lock (&sync_lock);
  __go_assert (i == 0);

  if (*ptr != old)
    ret = 0;
  else
    {
      *ptr = new;
      ret = 1;
    }

  i = pthread_mutex_unlock (&sync_lock);
  __go_assert (i == 0);

  return ret;
}

#endif

#ifndef HAVE_SYNC_FETCH_AND_ADD_4

uint32
__sync_fetch_and_add_4 (uint32*, uint32)
  __attribute__ ((visibility ("hidden")));

uint32
__sync_fetch_and_add_4 (uint32* ptr, uint32 add)
{
  int i;
  uint32 ret;

  i = pthread_mutex_lock (&sync_lock);
  __go_assert (i == 0);

  ret = *ptr;
  *ptr += add;

  i = pthread_mutex_unlock (&sync_lock);
  __go_assert (i == 0);

  return ret;
}

#endif

// Called to initialize a new m (including the bootstrap m).
void
runtime_minit(void)
{
	byte* stack;
	size_t stacksize;
	stack_t ss;

	// Initialize signal handling.
	runtime_m()->gsignal = runtime_malg(32*1024, &stack, &stacksize);	// OS X wants >=8K, Linux >=2K
	ss.ss_sp = stack;
	ss.ss_flags = 0;
	ss.ss_size = stacksize;
	if(sigaltstack(&ss, nil) < 0)
		*(int *)0xf1 = 0xf1;
}

// Temporary functions, which will be removed when we stop using
// condition variables.

void
runtime_cond_wait(pthread_cond_t* cond, pthread_mutex_t* mutex)
{
	int i;

	runtime_entersyscall();

	i = pthread_cond_wait(cond, mutex);
	if(i != 0)
		runtime_throw("pthread_cond_wait");
	i = pthread_mutex_unlock(mutex);
	if(i != 0)
		runtime_throw("pthread_mutex_unlock");

	runtime_exitsyscall();

	i = pthread_mutex_lock(mutex);
	if(i != 0)
		runtime_throw("pthread_mutex_lock");
}