/*
 * StarPU
 * Copyright (C) Université Bordeaux 1, CNRS 2008-2010 (see AUTHORS file)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 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 Lesser General Public License in COPYING.LGPL for more details.
 */

#ifndef __STARPU_UTIL_H__
#define __STARPU_UTIL_H__

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <starpu_config.h>
#include <starpu_task.h>

#ifdef __cplusplus
extern "C" {
#endif

#define STARPU_POISON_PTR	((void *)0xdeadbeef)

#define STARPU_MIN(a,b)	((a)<(b)?(a):(b))
#define STARPU_MAX(a,b)	((a)<(b)?(b):(a))

#ifdef STARPU_NO_ASSERT
#define STARPU_ASSERT(x)	do {} while(0);
#else
#  if defined(__CUDACC__) && defined(STARPU_HAVE_WINDOWS)
#    define STARPU_ASSERT(x)	do { if (!(x)) *(int*)NULL = 0; } while(0)
#  else
#    define STARPU_ASSERT(x)	assert(x)
#  endif
#endif

#define STARPU_ABORT()		abort()

#define STARPU_UNLIKELY(expr)          (__builtin_expect(!!(expr),0))
#define STARPU_LIKELY(expr)            (__builtin_expect(!!(expr),1))

#ifdef __GNUC__
#  define STARPU_ATTRIBUTE_UNUSED                  __attribute__((unused))
#else
#  define STARPU_ATTRIBUTE_UNUSED                  
#endif

#if defined(__i386__) || defined(__x86_64__)
static inline unsigned starpu_cmpxchg(unsigned *ptr, unsigned old, unsigned next) {
	__asm__ __volatile__("lock cmpxchgl %2,%1": "+a" (old), "+m" (*ptr) : "q" (next) : "memory");
	return old;
}
static inline unsigned starpu_xchg(unsigned *ptr, unsigned next) {
	/* Note: xchg is always locked already */
	__asm__ __volatile__("xchgl %1,%0": "+m" (*ptr), "+q" (next) : : "memory");
	return next;
}
#define STARPU_HAVE_XCHG
#endif

#define STARPU_ATOMIC_SOMETHING(name,expr) \
static inline unsigned starpu_atomic_##name(unsigned *ptr, unsigned value) { \
	unsigned old, next; \
	while (1) { \
		old = *ptr; \
		next = expr; \
		if (starpu_cmpxchg(ptr, old, next) == old) \
			break; \
	}; \
	return expr; \
}

#ifdef STARPU_HAVE_SYNC_FETCH_AND_ADD
#define STARPU_ATOMIC_ADD(ptr, value)  (__sync_fetch_and_add ((ptr), (value)) + (value))
#elif defined(STARPU_HAVE_XCHG)
STARPU_ATOMIC_SOMETHING(add, old + value)
#define STARPU_ATOMIC_ADD(ptr, value) starpu_atomic_add(ptr, value)
#endif

#ifdef STARPU_HAVE_SYNC_FETCH_AND_OR
#define STARPU_ATOMIC_OR(ptr, value)  (__sync_fetch_and_or ((ptr), (value)))
#elif defined(STARPU_HAVE_XCHG)
STARPU_ATOMIC_SOMETHING(or, old | value)
#define STARPU_ATOMIC_OR(ptr, value) starpu_atomic_or(ptr, value)
#endif

#ifdef STARPU_HAVE_SYNC_BOOL_COMPARE_AND_SWAP
#define STARPU_BOOL_COMPARE_AND_SWAP(ptr, old, value)  (__sync_bool_compare_and_swap ((ptr), (old), (value)))
#elif defined(STARPU_HAVE_XCHG)
#define STARPU_BOOL_COMPARE_AND_SWAP(ptr, old, value) (starpu_cmpxchg((ptr), (old), (value)) == (old))
#endif

#ifdef STARPU_HAVE_SYNC_LOCK_TEST_AND_SET
#define STARPU_TEST_AND_SET(ptr, value) (__sync_lock_test_and_set ((ptr), (value)))
#define STARPU_RELEASE(ptr) (__sync_lock_release ((ptr)))
#elif defined(STARPU_HAVE_XCHG)
#define STARPU_TEST_AND_SET(ptr, value) (starpu_xchg((ptr), (value)))
#define STARPU_RELEASE(ptr) (starpu_xchg((ptr), 0))
#endif

#ifdef STARPU_HAVE_SYNC_SYNCHRONIZE
#define STARPU_SYNCHRONIZE() __sync_synchronize()
#elif defined(__i386__)
#define STARPU_SYNCHRONIZE() __asm__ __volatile__("lock; addl $0,0(%%esp)" ::: "memory")
#elif defined(__x86_64__)
#define STARPU_SYNCHRONIZE() __asm__ __volatile__("mfence" ::: "memory")
#elif defined(__ppc__) || defined(__ppc64__)
#define STARPU_SYNCHRONIZE() __asm__ __volatile__("sync" ::: "memory")
#endif

static inline int starpu_get_env_number(const char *str)
{
	char *strval;

	strval = getenv(str);
	if (strval) {
		/* the env variable was actually set */
		unsigned val;
		char *check;

		val = (int)strtol(strval, &check, 10);
		STARPU_ASSERT(strcmp(check, "\0") == 0);

		//fprintf(stderr, "ENV %s WAS %d\n", str, val);
		return val;
	}
	else {
		/* there is no such env variable */
		//fprintf("There was no %s ENV\n", str);
		return -1;
	}
}

/* Add an event in the execution trace if FxT is enabled */
void starpu_trace_user_event(unsigned code);

/* Some helper functions for application using CUBLAS kernels */
void starpu_helper_cublas_init(void);
void starpu_helper_cublas_shutdown(void);

/* Call func(arg) on every worker matching the "where" mask (eg.
 * STARPU_CUDA|STARPU_CPU to execute the function on every CPU and every CUDA
 * device). This function is synchronous, but the different workers may execute
 * the function in parallel.
 * */
void starpu_execute_on_each_worker(void (*func)(void *), void *arg, uint32_t where);

/* This creates (and submits) an empty task that unlocks a tag once all its
 * dependencies are fulfilled. */
void starpu_create_sync_task(starpu_tag_t sync_tag, unsigned ndeps, starpu_tag_t *deps,
				void (*callback)(void *), void *callback_arg);

/* Constants used by the starpu_insert_task helper to determine the different types of argument */
#define STARPU_VALUE		(1<<3)	/* Pointer to a constant value */
#define STARPU_CALLBACK		(1<<4)	/* Callback function */
#define STARPU_CALLBACK_ARG	(1<<5)	/* Argument of the callback function (of type void *) */
#define STARPU_PRIORITY		(1<<6)	/* Priority associated to the task */

/* Wrapper to create a task. TODO document this interface */
void starpu_insert_task(starpu_codelet *cl, ...);

/* Retrieve the arguments of type STARPU_VALUE associated to a task
 * automatically created using starpu_insert_task. */
void starpu_unpack_cl_args(void *cl_arg, ...);

#ifdef __cplusplus
}
#endif

#endif // __STARPU_UTIL_H__