// -*- C++ -*-
// Copyright (C) 2007, 2008, 2009 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library 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 3, or (at your option) any later
// version.
// This library 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.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file parallel/compatibility.h
* @brief Compatibility layer, mostly concerned with atomic operations.
* This file is a GNU parallel extension to the Standard C++ Library.
*/
// Written by Felix Putze.
#ifndef _GLIBCXX_PARALLEL_COMPATIBILITY_H
#define _GLIBCXX_PARALLEL_COMPATIBILITY_H 1
#include <parallel/types.h>
#include <parallel/base.h>
#if defined(__SUNPRO_CC) && defined(__sparc)
#include <sys/atomic.h>
#endif
#if !defined(_WIN32) || defined (__CYGWIN__)
#include <sched.h>
#endif
#if defined(_MSC_VER)
#include <Windows.h>
#include <intrin.h>
#undef max
#undef min
#endif
#ifdef __MINGW32__
// Including <windows.h> will drag in all the windows32 names. Since
// that can cause user code portability problems, we just declare the
// one needed function here.
extern "C"
__attribute((dllimport)) void __attribute__((stdcall)) Sleep (unsigned long);
#endif
namespace __gnu_parallel
{
#if defined(__ICC)
template<typename must_be_int = int>
int32 faa32(int32* x, int32 inc)
{
asm volatile("lock xadd %0,%1"
: "=r" (inc), "=m" (*x)
: "0" (inc)
: "memory");
return inc;
}
#if defined(__x86_64)
template<typename must_be_int = int>
int64 faa64(int64* x, int64 inc)
{
asm volatile("lock xadd %0,%1"
: "=r" (inc), "=m" (*x)
: "0" (inc)
: "memory");
return inc;
}
#endif
#endif
// atomic functions only work on integers
/** @brief Add a value to a variable, atomically.
*
* Implementation is heavily platform-dependent.
* @param ptr Pointer to a 32-bit signed integer.
* @param addend Value to add.
*/
inline int32
fetch_and_add_32(volatile int32* ptr, int32 addend)
{
#if defined(__ICC) //x86 version
return _InterlockedExchangeAdd((void*)ptr, addend);
#elif defined(__ECC) //IA-64 version
return _InterlockedExchangeAdd((void*)ptr, addend);
#elif defined(__ICL) || defined(_MSC_VER)
return _InterlockedExchangeAdd(reinterpret_cast<volatile long*>(ptr),
addend);
#elif defined(__GNUC__)
return __sync_fetch_and_add(ptr, addend);
#elif defined(__SUNPRO_CC) && defined(__sparc)
volatile int32 before, after;
do
{
before = *ptr;
after = before + addend;
} while (atomic_cas_32((volatile unsigned int*)ptr, before,
after) != before);
return before;
#else //fallback, slow
#pragma message("slow fetch_and_add_32")
int32 res;
#pragma omp critical
{
res = *ptr;
*(ptr) += addend;
}
return res;
#endif
}
/** @brief Add a value to a variable, atomically.
*
* Implementation is heavily platform-dependent.
* @param ptr Pointer to a 64-bit signed integer.
* @param addend Value to add.
*/
inline int64
fetch_and_add_64(volatile int64* ptr, int64 addend)
{
#if defined(__ICC) && defined(__x86_64) //x86 version
return faa64<int>((int64*)ptr, addend);
#elif defined(__ECC) //IA-64 version
return _InterlockedExchangeAdd64((void*)ptr, addend);
#elif defined(__ICL) || defined(_MSC_VER)
#ifndef _WIN64
_GLIBCXX_PARALLEL_ASSERT(false); //not available in this case
return 0;
#else
return _InterlockedExchangeAdd64(ptr, addend);
#endif
#elif defined(__GNUC__) && defined(__x86_64)
return __sync_fetch_and_add(ptr, addend);
#elif defined(__GNUC__) && defined(__i386) && \
(defined(__i686) || defined(__pentium4) || defined(__athlon))
return __sync_fetch_and_add(ptr, addend);
#elif defined(__SUNPRO_CC) && defined(__sparc)
volatile int64 before, after;
do
{
before = *ptr;
after = before + addend;
} while (atomic_cas_64((volatile unsigned long long*)ptr, before,
after) != before);
return before;
#else //fallback, slow
#if defined(__GNUC__) && defined(__i386)
// XXX doesn't work with -march=native
//#warning "please compile with -march=i686 or better"
#endif
#pragma message("slow fetch_and_add_64")
int64 res;
#pragma omp critical
{
res = *ptr;
*(ptr) += addend;
}
return res;
#endif
}
/** @brief Add a value to a variable, atomically.
*
* Implementation is heavily platform-dependent.
* @param ptr Pointer to a signed integer.
* @param addend Value to add.
*/
template<typename T>
inline T
fetch_and_add(volatile T* ptr, T addend)
{
if (sizeof(T) == sizeof(int32))
return (T)fetch_and_add_32((volatile int32*) ptr, (int32)addend);
else if (sizeof(T) == sizeof(int64))
return (T)fetch_and_add_64((volatile int64*) ptr, (int64)addend);
else
_GLIBCXX_PARALLEL_ASSERT(false);
}
#if defined(__ICC)
template<typename must_be_int = int>
inline int32
cas32(volatile int32* ptr, int32 old, int32 nw)
{
int32 before;
__asm__ __volatile__("lock; cmpxchgl %1,%2"
: "=a"(before)
: "q"(nw), "m"(*(volatile long long*)(ptr)), "0"(old)
: "memory");
return before;
}
#if defined(__x86_64)
template<typename must_be_int = int>
inline int64
cas64(volatile int64 *ptr, int64 old, int64 nw)
{
int64 before;
__asm__ __volatile__("lock; cmpxchgq %1,%2"
: "=a"(before)
: "q"(nw), "m"(*(volatile long long*)(ptr)), "0"(old)
: "memory");
return before;
}
#endif
#endif
/** @brief Compare @c *ptr and @c comparand. If equal, let @c
* *ptr=replacement and return @c true, return @c false otherwise.
*
* Implementation is heavily platform-dependent.
* @param ptr Pointer to 32-bit signed integer.
* @param comparand Compare value.
* @param replacement Replacement value.
*/
inline bool
compare_and_swap_32(volatile int32* ptr, int32 comparand, int32 replacement)
{
#if defined(__ICC) //x86 version
return _InterlockedCompareExchange((void*)ptr, replacement,
comparand) == comparand;
#elif defined(__ECC) //IA-64 version
return _InterlockedCompareExchange((void*)ptr, replacement,
comparand) == comparand;
#elif defined(__ICL) || defined(_MSC_VER)
return _InterlockedCompareExchange(reinterpret_cast<volatile long*>(ptr),
replacement, comparand) == comparand;
#elif defined(__GNUC__)
return __sync_bool_compare_and_swap(ptr, comparand, replacement);
#elif defined(__SUNPRO_CC) && defined(__sparc)
return atomic_cas_32((volatile unsigned int*)ptr, comparand,
replacement) == comparand;
#else
#pragma message("slow compare_and_swap_32")
bool res = false;
#pragma omp critical
{
if (*ptr == comparand)
{
*ptr = replacement;
res = true;
}
}
return res;
#endif
}
/** @brief Compare @c *ptr and @c comparand. If equal, let @c
* *ptr=replacement and return @c true, return @c false otherwise.
*
* Implementation is heavily platform-dependent.
* @param ptr Pointer to 64-bit signed integer.
* @param comparand Compare value.
* @param replacement Replacement value.
*/
inline bool
compare_and_swap_64(volatile int64* ptr, int64 comparand, int64 replacement)
{
#if defined(__ICC) && defined(__x86_64) //x86 version
return cas64<int>(ptr, comparand, replacement) == comparand;
#elif defined(__ECC) //IA-64 version
return _InterlockedCompareExchange64((void*)ptr, replacement,
comparand) == comparand;
#elif defined(__ICL) || defined(_MSC_VER)
#ifndef _WIN64
_GLIBCXX_PARALLEL_ASSERT(false); //not available in this case
return 0;
#else
return _InterlockedCompareExchange64(ptr, replacement,
comparand) == comparand;
#endif
#elif defined(__GNUC__) && defined(__x86_64)
return __sync_bool_compare_and_swap(ptr, comparand, replacement);
#elif defined(__GNUC__) && defined(__i386) && \
(defined(__i686) || defined(__pentium4) || defined(__athlon))
return __sync_bool_compare_and_swap(ptr, comparand, replacement);
#elif defined(__SUNPRO_CC) && defined(__sparc)
return atomic_cas_64((volatile unsigned long long*)ptr,
comparand, replacement) == comparand;
#else
#if defined(__GNUC__) && defined(__i386)
// XXX -march=native
//#warning "please compile with -march=i686 or better"
#endif
#pragma message("slow compare_and_swap_64")
bool res = false;
#pragma omp critical
{
if (*ptr == comparand)
{
*ptr = replacement;
res = true;
}
}
return res;
#endif
}
/** @brief Compare @c *ptr and @c comparand. If equal, let @c
* *ptr=replacement and return @c true, return @c false otherwise.
*
* Implementation is heavily platform-dependent.
* @param ptr Pointer to signed integer.
* @param comparand Compare value.
* @param replacement Replacement value. */
template<typename T>
inline bool
compare_and_swap(volatile T* ptr, T comparand, T replacement)
{
if (sizeof(T) == sizeof(int32))
return compare_and_swap_32((volatile int32*) ptr, (int32)comparand, (int32)replacement);
else if (sizeof(T) == sizeof(int64))
return compare_and_swap_64((volatile int64*) ptr, (int64)comparand, (int64)replacement);
else
_GLIBCXX_PARALLEL_ASSERT(false);
}
/** @brief Yield the control to another thread, without waiting for
the end to the time slice. */
inline void
yield()
{
#if defined (_WIN32) && !defined (__CYGWIN__)
Sleep(0);
#else
sched_yield();
#endif
}
} // end namespace
#endif /* _GLIBCXX_PARALLEL_COMPATIBILITY_H */