/*-
   * Copyright (c) 2011 Ed Schouten <ed@FreeBSD.org>
   *                    David Chisnall <theraven@FreeBSD.org>
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * $FreeBSD$
   */
  
  /* This file was imported into RIOT from newlib 2.3.0 */
  
  #ifndef STDATOMIC_H
  #define STDATOMIC_H
  
  #include <sys/cdefs.h>
  #include <sys/_types.h>
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  #if __has_extension(c_atomic) || __has_extension(cxx_atomic)
  #define __CLANG_ATOMICS
  #elif __GNUC_PREREQ__(4, 7)
  #define __GNUC_ATOMICS
  #elif defined(__GNUC__)
  #define __SYNC_ATOMICS
  #else
  #error "stdatomic.h does not support your compiler"
  #endif
  
  /*
   * 7.17.1 Atomic lock-free macros.
   */
  
  #ifdef __GCC_ATOMIC_BOOL_LOCK_FREE
  #define ATOMIC_BOOL_LOCK_FREE       __GCC_ATOMIC_BOOL_LOCK_FREE
  #endif
  #ifdef __GCC_ATOMIC_CHAR_LOCK_FREE
  #define ATOMIC_CHAR_LOCK_FREE       __GCC_ATOMIC_CHAR_LOCK_FREE
  #endif
  #ifdef __GCC_ATOMIC_CHAR16_T_LOCK_FREE
  #define ATOMIC_CHAR16_T_LOCK_FREE   __GCC_ATOMIC_CHAR16_T_LOCK_FREE
  #endif
  #ifdef __GCC_ATOMIC_CHAR32_T_LOCK_FREE
  #define ATOMIC_CHAR32_T_LOCK_FREE   __GCC_ATOMIC_CHAR32_T_LOCK_FREE
  #endif
  #ifdef __GCC_ATOMIC_WCHAR_T_LOCK_FREE
  #define ATOMIC_WCHAR_T_LOCK_FREE    __GCC_ATOMIC_WCHAR_T_LOCK_FREE
  #endif
  #ifdef __GCC_ATOMIC_SHORT_LOCK_FREE
  #define ATOMIC_SHORT_LOCK_FREE      __GCC_ATOMIC_SHORT_LOCK_FREE
  #endif
  #ifdef __GCC_ATOMIC_INT_LOCK_FREE
  #define ATOMIC_INT_LOCK_FREE        __GCC_ATOMIC_INT_LOCK_FREE
  #endif
  #ifdef __GCC_ATOMIC_LONG_LOCK_FREE
  #define ATOMIC_LONG_LOCK_FREE       __GCC_ATOMIC_LONG_LOCK_FREE
  #endif
  #ifdef __GCC_ATOMIC_LLONG_LOCK_FREE
  #define ATOMIC_LLONG_LOCK_FREE      __GCC_ATOMIC_LLONG_LOCK_FREE
  #endif
  #ifdef __GCC_ATOMIC_POINTER_LOCK_FREE
  #define ATOMIC_POINTER_LOCK_FREE    __GCC_ATOMIC_POINTER_LOCK_FREE
  #endif
  
  /*
   * 7.17.2 Initialization.
   */
  
  #if defined(__CLANG_ATOMICS)
  #define ATOMIC_VAR_INIT(value)      (value)
  #define atomic_init(obj, value)     __c11_atomic_init(obj, value)
  #else
  #define ATOMIC_VAR_INIT(value)      { .__val = (value) }
  #define atomic_init(obj, value)     ((void)((obj)->__val = (value)))
  #endif
  
  /*
   * Clang and recent GCC both provide predefined macros for the memory
   * orderings.  If we are using a compiler that doesn't define them, use the
   * clang values - these will be ignored in the fallback path.
   */
  
  #ifndef __ATOMIC_RELAXED
  #define __ATOMIC_RELAXED        0
  #endif
  #ifndef __ATOMIC_CONSUME
  #define __ATOMIC_CONSUME        1
  #endif
  #ifndef __ATOMIC_ACQUIRE
  #define __ATOMIC_ACQUIRE        2
  #endif
  #ifndef __ATOMIC_RELEASE
  #define __ATOMIC_RELEASE        3
  #endif
  #ifndef __ATOMIC_ACQ_REL
  #define __ATOMIC_ACQ_REL        4
  #endif
  #ifndef __ATOMIC_SEQ_CST
  #define __ATOMIC_SEQ_CST        5
  #endif
  
  /*
   * 7.17.3 Order and consistency.
   *
   * The memory_order_* constants that denote the barrier behaviour of the
   * atomic operations.
   */
  
  typedef enum {
      memory_order_relaxed = __ATOMIC_RELAXED,
      memory_order_consume = __ATOMIC_CONSUME,
      memory_order_acquire = __ATOMIC_ACQUIRE,
      memory_order_release = __ATOMIC_RELEASE,
      memory_order_acq_rel = __ATOMIC_ACQ_REL,
      memory_order_seq_cst = __ATOMIC_SEQ_CST
  } memory_order;
  
  /*
   * 7.17.4 Fences.
   */
  
  static __inline void
  atomic_thread_fence(memory_order __order)
  {
  
  #ifdef __CLANG_ATOMICS
      __c11_atomic_thread_fence(__order);
  #elif defined(__GNUC_ATOMICS)
      __atomic_thread_fence(__order);
  #else
      (void) __order;
      __sync_synchronize();
  #endif
  }
  
  static __inline void
  atomic_signal_fence(memory_order __order)
  {
  
  #ifdef __CLANG_ATOMICS
      __c11_atomic_signal_fence(__order);
  #elif defined(__GNUC_ATOMICS)
      __atomic_signal_fence(__order);
  #else
      (void) __order;
      __asm volatile ("" ::: "memory");
  #endif
  }
  
  /*
   * 7.17.5 Lock-free property.
   */
  
  #if defined(_KERNEL)
  /* Atomics in kernelspace are always lock-free. */
  #define atomic_is_lock_free(obj) \
      ((void)(obj), (_Bool)1)
  #elif defined(__CLANG_ATOMICS)
  #define atomic_is_lock_free(obj) \
      __atomic_is_lock_free(sizeof(*(obj)), obj)
  #elif defined(__GNUC_ATOMICS)
  #define atomic_is_lock_free(obj) \
      __atomic_is_lock_free(sizeof((obj)->__val), &(obj)->__val)
  #else
  #define atomic_is_lock_free(obj) \
      ((void)(obj), sizeof((obj)->__val) <= sizeof(void *))
  #endif
  
  /*
   * 7.17.6 Atomic integer types.
   */
  
  typedef _Atomic(_Bool)              atomic_bool;
  typedef _Atomic(char)               atomic_char;
  typedef _Atomic(signed char)        atomic_schar;
  typedef _Atomic(unsigned char)      atomic_uchar;
  typedef _Atomic(short)              atomic_short;
  typedef _Atomic(unsigned short)     atomic_ushort;
  typedef _Atomic(int)                atomic_int;
  typedef _Atomic(unsigned int)       atomic_uint;
  typedef _Atomic(long)               atomic_long;
  typedef _Atomic(unsigned long)      atomic_ulong;
  typedef _Atomic(long long)          atomic_llong;
  typedef _Atomic(unsigned long long) atomic_ullong;
  #if 0
  typedef _Atomic(__char16_t)         atomic_char16_t;
  typedef _Atomic(__char32_t)         atomic_char32_t;
  #endif
  typedef _Atomic(wchar_t)            atomic_wchar_t;
  typedef _Atomic(int_least8_t)       atomic_int_least8_t;
  typedef _Atomic(uint_least8_t)      atomic_uint_least8_t;
  typedef _Atomic(int_least16_t)      atomic_int_least16_t;
  typedef _Atomic(uint_least16_t)     atomic_uint_least16_t;
  typedef _Atomic(int_least32_t)      atomic_int_least32_t;
  typedef _Atomic(uint_least32_t)     atomic_uint_least32_t;
  typedef _Atomic(int_least64_t)      atomic_int_least64_t;
  typedef _Atomic(uint_least64_t)     atomic_uint_least64_t;
  typedef _Atomic(int_fast8_t)        atomic_int_fast8_t;
  typedef _Atomic(uint_fast8_t)       atomic_uint_fast8_t;
  typedef _Atomic(int_fast16_t)       atomic_int_fast16_t;
  typedef _Atomic(uint_fast16_t)      atomic_uint_fast16_t;
  typedef _Atomic(int_fast32_t)       atomic_int_fast32_t;
  typedef _Atomic(uint_fast32_t)      atomic_uint_fast32_t;
  typedef _Atomic(int_fast64_t)       atomic_int_fast64_t;
  typedef _Atomic(uint_fast64_t)      atomic_uint_fast64_t;
  typedef _Atomic(intptr_t)           atomic_intptr_t;
  typedef _Atomic(uintptr_t)          atomic_uintptr_t;
  typedef _Atomic(size_t)             atomic_size_t;
  typedef _Atomic(ptrdiff_t)          atomic_ptrdiff_t;
  typedef _Atomic(intmax_t)           atomic_intmax_t;
  typedef _Atomic(uintmax_t)          atomic_uintmax_t;
  
  /*
   * 7.17.7 Operations on atomic types.
   */
  
  /*
   * Compiler-specific operations.
   */
  
  #if defined(__CLANG_ATOMICS)
  #define atomic_compare_exchange_strong_explicit(object, expected,   \
      desired, success, failure)                      \
      __c11_atomic_compare_exchange_strong(object, expected, desired, \
          success, failure)
  #define atomic_compare_exchange_weak_explicit(object, expected,     \
      desired, success, failure)                      \
      __c11_atomic_compare_exchange_weak(object, expected, desired,   \
          success, failure)
  #define atomic_exchange_explicit(object, desired, order)        \
      __c11_atomic_exchange(object, desired, order)
  #define atomic_fetch_add_explicit(object, operand, order)       \
      __c11_atomic_fetch_add(object, operand, order)
  #define atomic_fetch_and_explicit(object, operand, order)       \
      __c11_atomic_fetch_and(object, operand, order)
  #define atomic_fetch_or_explicit(object, operand, order)        \
      __c11_atomic_fetch_or(object, operand, order)
  #define atomic_fetch_sub_explicit(object, operand, order)       \
      __c11_atomic_fetch_sub(object, operand, order)
  #define atomic_fetch_xor_explicit(object, operand, order)       \
      __c11_atomic_fetch_xor(object, operand, order)
  #define atomic_load_explicit(object, order)             \
      __c11_atomic_load(object, order)
  #define atomic_store_explicit(object, desired, order)           \
      __c11_atomic_store(object, desired, order)
  #elif defined(__GNUC_ATOMICS)
  #define atomic_compare_exchange_strong_explicit(object, expected,   \
      desired, success, failure)                      \
      __atomic_compare_exchange_n(&(object)->__val, expected,     \
          desired, 0, success, failure)
  #define atomic_compare_exchange_weak_explicit(object, expected,     \
      desired, success, failure)                      \
      __atomic_compare_exchange_n(&(object)->__val, expected,     \
          desired, 1, success, failure)
  #define atomic_exchange_explicit(object, desired, order)        \
      __atomic_exchange_n(&(object)->__val, desired, order)
  #define atomic_fetch_add_explicit(object, operand, order)       \
      __atomic_fetch_add(&(object)->__val, operand, order)
  #define atomic_fetch_and_explicit(object, operand, order)       \
      __atomic_fetch_and(&(object)->__val, operand, order)
  #define atomic_fetch_or_explicit(object, operand, order)        \
      __atomic_fetch_or(&(object)->__val, operand, order)
  #define atomic_fetch_sub_explicit(object, operand, order)       \
      __atomic_fetch_sub(&(object)->__val, operand, order)
  #define atomic_fetch_xor_explicit(object, operand, order)       \
      __atomic_fetch_xor(&(object)->__val, operand, order)
  #define atomic_load_explicit(object, order)             \
      __atomic_load_n(&(object)->__val, order)
  #define atomic_store_explicit(object, desired, order)           \
      __atomic_store_n(&(object)->__val, desired, order)
  #else
  #define __atomic_apply_stride(object, operand) \
      (((__typeof__((object)->__val))0) + (operand))
  #define atomic_compare_exchange_strong_explicit(object, expected,   \
      desired, success, failure)  __extension__ ({            \
      __typeof__(expected) __ep = (expected);             \
      __typeof__(*__ep) __e = *__ep;                  \
      (void)(success); (void)(failure);               \
      (_Bool)((*__ep = __sync_val_compare_and_swap(&(object)->__val,  \
          __e, desired)) == __e);                 \
  })
  #define atomic_compare_exchange_weak_explicit(object, expected,     \
      desired, success, failure)                      \
      atomic_compare_exchange_strong_explicit(object, expected,   \
          desired, success, failure)
  #if __has_builtin(__sync_swap)
  /* Clang provides a full-barrier atomic exchange - use it if available. */
  #define atomic_exchange_explicit(object, desired, order)        \
      __sync_swap(&(object)->__val, desired)
  #else
  /*
   * __sync_lock_test_and_set() is only an acquire barrier in theory (although in
   * practice it is usually a full barrier) so we need an explicit barrier before
   * it.
   */
  #define atomic_exchange_explicit(object, desired, order)        \
  __extension__ ({                            \
      __typeof__(object) __o = (object);              \
      __typeof__(desired) __d = (desired);                \
      (void)(order);                          \
      __sync_synchronize();                       \
      __sync_lock_test_and_set(&(__o)->__val, __d);           \
  })
  #endif
  /* Ignoring the order argument when using __sync builtins */
  #define atomic_fetch_add_explicit(object, operand, order)       \
      __sync_fetch_and_add(&(object)->__val,      \
          __atomic_apply_stride(object, operand))
  #define atomic_fetch_and_explicit(object, operand, order)       \
      __sync_fetch_and_and(&(object)->__val, operand)
  #define atomic_fetch_or_explicit(object, operand, order)        \
      __sync_fetch_and_or(&(object)->__val, operand)
  #define atomic_fetch_sub_explicit(object, operand, order)       \
      __sync_fetch_and_sub(&(object)->__val,      \
          __atomic_apply_stride(object, operand))
  #define atomic_fetch_xor_explicit(object, operand, order)       \
      __sync_fetch_and_xor(&(object)->__val, operand)
  #define atomic_load_explicit(object, order)             \
      __sync_fetch_and_add(&(object)->__val, 0)
  #define atomic_store_explicit(object, desired, order)           \
      ((void)atomic_exchange_explicit(object, desired, order))
  #endif
  
  /*
   * Convenience functions.
   *
   * Don't provide these in kernel space. In kernel space, we should be
   * disciplined enough to always provide explicit barriers.
   */
  
  #ifndef _KERNEL
  #define atomic_compare_exchange_strong(object, expected, desired)   \
      atomic_compare_exchange_strong_explicit(object, expected,   \
          desired, memory_order_seq_cst, memory_order_seq_cst)
  #define atomic_compare_exchange_weak(object, expected, desired)     \
      atomic_compare_exchange_weak_explicit(object, expected,     \
          desired, memory_order_seq_cst, memory_order_seq_cst)
  #define atomic_exchange(object, desired)                \
      atomic_exchange_explicit(object, desired, memory_order_seq_cst)
  #define atomic_fetch_add(object, operand)               \
      atomic_fetch_add_explicit(object, operand, memory_order_seq_cst)
  #define atomic_fetch_and(object, operand)               \
      atomic_fetch_and_explicit(object, operand, memory_order_seq_cst)
  #define atomic_fetch_or(object, operand)                \
      atomic_fetch_or_explicit(object, operand, memory_order_seq_cst)
  #define atomic_fetch_sub(object, operand)               \
      atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst)
  #define atomic_fetch_xor(object, operand)               \
      atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst)
  #define atomic_load(object)                     \
      atomic_load_explicit(object, memory_order_seq_cst)
  #define atomic_store(object, desired)                   \
      atomic_store_explicit(object, desired, memory_order_seq_cst)
  #endif /* !_KERNEL */
  
  /*
   * 7.17.8 Atomic flag type and operations.
   *
   * XXX: Assume atomic_bool can be used as an atomic_flag. Is there some
   * kind of compiler built-in type we could use?
   */
  
  typedef struct {
      atomic_bool __flag;
  } atomic_flag;
  
  #define ATOMIC_FLAG_INIT        { ATOMIC_VAR_INIT(0) }
  
  static __inline _Bool
  atomic_flag_test_and_set_explicit(volatile atomic_flag *__object,
      memory_order __order)
  {
      return (atomic_exchange_explicit(&__object->__flag, 1, __order));
  }
  
  static __inline void
  atomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order)
  {
  
      atomic_store_explicit(&__object->__flag, 0, __order);
  }
  
  #ifndef _KERNEL
  static __inline _Bool
  atomic_flag_test_and_set(volatile atomic_flag *__object)
  {
  
      return (atomic_flag_test_and_set_explicit(__object,
          memory_order_seq_cst));
  }
  
  static __inline void
  atomic_flag_clear(volatile atomic_flag *__object)
  {
  
      atomic_flag_clear_explicit(__object, memory_order_seq_cst);
  }
  #endif /* !_KERNEL */
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* STDATOMIC_H */