YouCompleteMe/cpp/BoostParts/boost/interprocess/detail/atomic.hpp
2013-03-16 11:00:13 -07:00

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//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2006-2012
// (C) Copyright Markus Schoepflin 2007
// (C) Copyright Bryce Lelbach 2010
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/interprocess for documentation.
//
//////////////////////////////////////////////////////////////////////////////
#ifndef BOOST_INTERPROCESS_DETAIL_ATOMIC_HPP
#define BOOST_INTERPROCESS_DETAIL_ATOMIC_HPP
#include <boost/interprocess/detail/config_begin.hpp>
#include <boost/interprocess/detail/workaround.hpp>
#include <boost/cstdint.hpp>
namespace boost{
namespace interprocess{
namespace ipcdetail{
//! Atomically increment an boost::uint32_t by 1
//! "mem": pointer to the object
//! Returns the old value pointed to by mem
inline boost::uint32_t atomic_inc32(volatile boost::uint32_t *mem);
//! Atomically read an boost::uint32_t from memory
inline boost::uint32_t atomic_read32(volatile boost::uint32_t *mem);
//! Atomically set an boost::uint32_t in memory
//! "mem": pointer to the object
//! "param": val value that the object will assume
inline void atomic_write32(volatile boost::uint32_t *mem, boost::uint32_t val);
//! Compare an boost::uint32_t's value with "cmp".
//! If they are the same swap the value with "with"
//! "mem": pointer to the value
//! "with": what to swap it with
//! "cmp": the value to compare it to
//! Returns the old value of *mem
inline boost::uint32_t atomic_cas32
(volatile boost::uint32_t *mem, boost::uint32_t with, boost::uint32_t cmp);
} //namespace ipcdetail{
} //namespace interprocess{
} //namespace boost{
#if (defined BOOST_INTERPROCESS_WINDOWS)
#include <boost/interprocess/detail/win32_api.hpp>
namespace boost{
namespace interprocess{
namespace ipcdetail{
//! Atomically decrement an boost::uint32_t by 1
//! "mem": pointer to the atomic value
//! Returns the old value pointed to by mem
inline boost::uint32_t atomic_dec32(volatile boost::uint32_t *mem)
{ return winapi::interlocked_decrement(reinterpret_cast<volatile long*>(mem)) + 1; }
//! Atomically increment an apr_uint32_t by 1
//! "mem": pointer to the object
//! Returns the old value pointed to by mem
inline boost::uint32_t atomic_inc32(volatile boost::uint32_t *mem)
{ return winapi::interlocked_increment(reinterpret_cast<volatile long*>(mem))-1; }
//! Atomically read an boost::uint32_t from memory
inline boost::uint32_t atomic_read32(volatile boost::uint32_t *mem)
{ return *mem; }
//! Atomically set an boost::uint32_t in memory
//! "mem": pointer to the object
//! "param": val value that the object will assume
inline void atomic_write32(volatile boost::uint32_t *mem, boost::uint32_t val)
{ winapi::interlocked_exchange(reinterpret_cast<volatile long*>(mem), val); }
//! Compare an boost::uint32_t's value with "cmp".
//! If they are the same swap the value with "with"
//! "mem": pointer to the value
//! "with": what to swap it with
//! "cmp": the value to compare it to
//! Returns the old value of *mem
inline boost::uint32_t atomic_cas32
(volatile boost::uint32_t *mem, boost::uint32_t with, boost::uint32_t cmp)
{ return winapi::interlocked_compare_exchange(reinterpret_cast<volatile long*>(mem), with, cmp); }
} //namespace ipcdetail{
} //namespace interprocess{
} //namespace boost{
#elif defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
namespace boost {
namespace interprocess {
namespace ipcdetail{
//! Compare an boost::uint32_t's value with "cmp".
//! If they are the same swap the value with "with"
//! "mem": pointer to the value
//! "with" what to swap it with
//! "cmp": the value to compare it to
//! Returns the old value of *mem
inline boost::uint32_t atomic_cas32
(volatile boost::uint32_t *mem, boost::uint32_t with, boost::uint32_t cmp)
{
boost::uint32_t prev = cmp;
// This version by Mans Rullgard of Pathscale
__asm__ __volatile__ ( "lock\n\t"
"cmpxchg %2,%0"
: "+m"(*mem), "+a"(prev)
: "r"(with)
: "cc");
return prev;
}
//! Atomically add 'val' to an boost::uint32_t
//! "mem": pointer to the object
//! "val": amount to add
//! Returns the old value pointed to by mem
inline boost::uint32_t atomic_add32
(volatile boost::uint32_t *mem, boost::uint32_t val)
{
// int r = *pw;
// *mem += val;
// return r;
int r;
asm volatile
(
"lock\n\t"
"xadd %1, %0":
"+m"( *mem ), "=r"( r ): // outputs (%0, %1)
"1"( val ): // inputs (%2 == %1)
"memory", "cc" // clobbers
);
return r;
}
//! Atomically increment an apr_uint32_t by 1
//! "mem": pointer to the object
//! Returns the old value pointed to by mem
inline boost::uint32_t atomic_inc32(volatile boost::uint32_t *mem)
{ return atomic_add32(mem, 1); }
//! Atomically decrement an boost::uint32_t by 1
//! "mem": pointer to the atomic value
//! Returns the old value pointed to by mem
inline boost::uint32_t atomic_dec32(volatile boost::uint32_t *mem)
{ return atomic_add32(mem, (boost::uint32_t)-1); }
//! Atomically read an boost::uint32_t from memory
inline boost::uint32_t atomic_read32(volatile boost::uint32_t *mem)
{ return *mem; }
//! Atomically set an boost::uint32_t in memory
//! "mem": pointer to the object
//! "param": val value that the object will assume
inline void atomic_write32(volatile boost::uint32_t *mem, boost::uint32_t val)
{ *mem = val; }
} //namespace ipcdetail{
} //namespace interprocess{
} //namespace boost{
#elif defined(__GNUC__) && (defined(__PPC__) || defined(__ppc__))
namespace boost {
namespace interprocess {
namespace ipcdetail{
//! Atomically add 'val' to an boost::uint32_t
//! "mem": pointer to the object
//! "val": amount to add
//! Returns the old value pointed to by mem
inline boost::uint32_t atomic_add32(volatile boost::uint32_t *mem, boost::uint32_t val)
{
boost::uint32_t prev, temp;
asm volatile ("1:\n\t"
"lwarx %0,0,%2\n\t"
"add %1,%0,%3\n\t"
"stwcx. %1,0,%2\n\t"
"bne- 1b"
: "=&r" (prev), "=&r" (temp)
: "b" (mem), "r" (val)
: "cc", "memory");
return prev;
}
//! Compare an boost::uint32_t's value with "cmp".
//! If they are the same swap the value with "with"
//! "mem": pointer to the value
//! "with" what to swap it with
//! "cmp": the value to compare it to
//! Returns the old value of *mem
inline boost::uint32_t atomic_cas32
(volatile boost::uint32_t *mem, boost::uint32_t with, boost::uint32_t cmp)
{
boost::uint32_t prev;
asm volatile ("1:\n\t"
"lwarx %0,0,%1\n\t"
"cmpw %0,%3\n\t"
"bne- 2f\n\t"
"stwcx. %2,0,%1\n\t"
"bne- 1b\n\t"
"2:"
: "=&r"(prev)
: "b" (mem), "r"(cmp), "r" (with)
: "cc", "memory");
return prev;
}
//! Atomically increment an apr_uint32_t by 1
//! "mem": pointer to the object
//! Returns the old value pointed to by mem
inline boost::uint32_t atomic_inc32(volatile boost::uint32_t *mem)
{ return atomic_add32(mem, 1); }
//! Atomically decrement an boost::uint32_t by 1
//! "mem": pointer to the atomic value
//! Returns the old value pointed to by mem
inline boost::uint32_t atomic_dec32(volatile boost::uint32_t *mem)
{ return atomic_add32(mem, boost::uint32_t(-1u)); }
//! Atomically read an boost::uint32_t from memory
inline boost::uint32_t atomic_read32(volatile boost::uint32_t *mem)
{ return *mem; }
//! Atomically set an boost::uint32_t in memory
//! "mem": pointer to the object
//! "param": val value that the object will assume
inline void atomic_write32(volatile boost::uint32_t *mem, boost::uint32_t val)
{ *mem = val; }
} //namespace ipcdetail{
} //namespace interprocess{
} //namespace boost{
#elif (defined(sun) || defined(__sun))
#include <atomic.h>
namespace boost{
namespace interprocess{
namespace ipcdetail{
//! Atomically add 'val' to an boost::uint32_t
//! "mem": pointer to the object
//! "val": amount to add
//! Returns the old value pointed to by mem
inline boost::uint32_t atomic_add32(volatile boost::uint32_t *mem, boost::uint32_t val)
{ return atomic_add_32_nv(reinterpret_cast<volatile ::uint32_t*>(mem), (int32_t)val) - val; }
//! Compare an boost::uint32_t's value with "cmp".
//! If they are the same swap the value with "with"
//! "mem": pointer to the value
//! "with" what to swap it with
//! "cmp": the value to compare it to
//! Returns the old value of *mem
inline boost::uint32_t atomic_cas32
(volatile boost::uint32_t *mem, boost::uint32_t with, boost::uint32_t cmp)
{ return atomic_cas_32(reinterpret_cast<volatile ::uint32_t*>(mem), cmp, with); }
//! Atomically increment an apr_uint32_t by 1
//! "mem": pointer to the object
//! Returns the old value pointed to by mem
inline boost::uint32_t atomic_inc32(volatile boost::uint32_t *mem)
{ return atomic_add_32_nv(reinterpret_cast<volatile ::uint32_t*>(mem), 1) - 1; }
//! Atomically decrement an boost::uint32_t by 1
//! "mem": pointer to the atomic value
//! Returns the old value pointed to by mem
inline boost::uint32_t atomic_dec32(volatile boost::uint32_t *mem)
{ return atomic_add_32_nv(reinterpret_cast<volatile ::uint32_t*>(mem), (boost::uint32_t)-1) + 1; }
//! Atomically read an boost::uint32_t from memory
inline boost::uint32_t atomic_read32(volatile boost::uint32_t *mem)
{ return *mem; }
//! Atomically set an boost::uint32_t in memory
//! "mem": pointer to the object
//! "param": val value that the object will assume
inline void atomic_write32(volatile boost::uint32_t *mem, boost::uint32_t val)
{ *mem = val; }
} //namespace ipcdetail{
} //namespace interprocess{
} //namespace boost{
#elif defined(__osf__) && defined(__DECCXX)
#include <machine/builtins.h>
#include <c_asm.h>
namespace boost{
namespace interprocess{
namespace ipcdetail{
//! Atomically decrement a uint32_t by 1
//! "mem": pointer to the atomic value
//! Returns the old value pointed to by mem
//! Acquire, memory barrier after decrement.
inline boost::uint32_t atomic_dec32(volatile boost::uint32_t *mem)
{ boost::uint32_t old_val = __ATOMIC_DECREMENT_LONG(mem); __MB(); return old_val; }
//! Atomically increment a uint32_t by 1
//! "mem": pointer to the object
//! Returns the old value pointed to by mem
//! Release, memory barrier before increment.
inline boost::uint32_t atomic_inc32(volatile boost::uint32_t *mem)
{ __MB(); return __ATOMIC_INCREMENT_LONG(mem); }
// Rational for the implementation of the atomic read and write functions.
//
// 1. The Alpha Architecture Handbook requires that access to a byte,
// an aligned word, an aligned longword, or an aligned quadword is
// atomic. (See 'Alpha Architecture Handbook', version 4, chapter 5.2.2.)
//
// 2. The CXX User's Guide states that volatile quantities are accessed
// with single assembler instructions, and that a compilation error
// occurs when declaring a quantity as volatile which is not properly
// aligned.
//! Atomically read an boost::uint32_t from memory
//! Acquire, memory barrier after load.
inline boost::uint32_t atomic_read32(volatile boost::uint32_t *mem)
{ boost::uint32_t old_val = *mem; __MB(); return old_val; }
//! Atomically set an boost::uint32_t in memory
//! "mem": pointer to the object
//! "param": val value that the object will assume
//! Release, memory barrier before store.
inline void atomic_write32(volatile boost::uint32_t *mem, boost::uint32_t val)
{ __MB(); *mem = val; }
//! Compare an boost::uint32_t's value with "cmp".
//! If they are the same swap the value with "with"
//! "mem": pointer to the value
//! "with" what to swap it with
//! "cmp": the value to compare it to
//! Returns the old value of *mem
//! Memory barrier between load and store.
inline boost::uint32_t atomic_cas32(
volatile boost::uint32_t *mem, boost::uint32_t with, boost::uint32_t cmp)
{
// Note:
//
// Branch prediction prefers backward branches, and the Alpha Architecture
// Handbook explicitely states that the loop should not be implemented like
// it is below. (See chapter 4.2.5.) Therefore the code should probably look
// like this:
//
// return asm(
// "10: ldl_l %v0,(%a0) ;"
// " cmpeq %v0,%a2,%t0 ;"
// " beq %t0,20f ;"
// " mb ;"
// " mov %a1,%t0 ;"
// " stl_c %t0,(%a0) ;"
// " beq %t0,30f ;"
// "20: ret ;"
// "30: br 10b;",
// mem, with, cmp);
//
// But as the compiler always transforms this into the form where a backward
// branch is taken on failure, we can as well implement it in the straight
// forward form, as this is what it will end up in anyway.
return asm(
"10: ldl_l %v0,(%a0) ;" // load prev value from mem and lock mem
" cmpeq %v0,%a2,%t0 ;" // compare with given value
" beq %t0,20f ;" // if not equal, we're done
" mb ;" // memory barrier
" mov %a1,%t0 ;" // load new value into scratch register
" stl_c %t0,(%a0) ;" // store new value to locked mem (overwriting scratch)
" beq %t0,10b ;" // store failed because lock has been stolen, retry
"20: ",
mem, with, cmp);
}
} //namespace ipcdetail{
} //namespace interprocess{
} //namespace boost{
#elif defined(__IBMCPP__) && (__IBMCPP__ >= 800) && defined(_AIX)
#include <builtins.h>
namespace boost {
namespace interprocess {
namespace ipcdetail{
//first define boost::uint32_t versions of __lwarx and __stwcx to avoid poluting
//all the functions with casts
//! From XLC documenation :
//! This function can be used with a subsequent stwcxu call to implement a
//! read-modify-write on a specified memory location. The two functions work
//! together to ensure that if the store is successfully performed, no other
//! processor or mechanism can modify the target doubleword between the time
//! lwarxu function is executed and the time the stwcxu functio ncompletes.
//! "mem" : pointer to the object
//! Returns the value at pointed to by mem
inline boost::uint32_t lwarxu(volatile boost::uint32_t *mem)
{
return static_cast<boost::uint32_t>(__lwarx(reinterpret_cast<volatile int*>(mem)));
}
//! "mem" : pointer to the object
//! "val" : the value to store
//! Returns true if the update of mem is successful and false if it is
//!unsuccessful
inline bool stwcxu(volatile boost::uint32_t* mem, boost::uint32_t val)
{
return (__stwcx(reinterpret_cast<volatile int*>(mem), static_cast<int>(val)) != 0);
}
//! "mem": pointer to the object
//! "val": amount to add
//! Returns the old value pointed to by mem
inline boost::uint32_t atomic_add32
(volatile boost::uint32_t *mem, boost::uint32_t val)
{
boost::uint32_t oldValue;
do
{
oldValue = lwarxu(mem);
}while (!stwcxu(mem, oldValue+val));
return oldValue;
}
//! Atomically increment an apr_uint32_t by 1
//! "mem": pointer to the object
//! Returns the old value pointed to by mem
inline boost::uint32_t atomic_inc32(volatile boost::uint32_t *mem)
{ return atomic_add32(mem, 1); }
//! Atomically decrement an boost::uint32_t by 1
//! "mem": pointer to the atomic value
//! Returns the old value pointed to by mem
inline boost::uint32_t atomic_dec32(volatile boost::uint32_t *mem)
{ return atomic_add32(mem, (boost::uint32_t)-1); }
//! Atomically read an boost::uint32_t from memory
inline boost::uint32_t atomic_read32(volatile boost::uint32_t *mem)
{ return *mem; }
//! Compare an boost::uint32_t's value with "cmp".
//! If they are the same swap the value with "with"
//! "mem": pointer to the value
//! "with" what to swap it with
//! "cmp": the value to compare it to
//! Returns the old value of *mem
inline boost::uint32_t atomic_cas32
(volatile boost::uint32_t *mem, boost::uint32_t with, boost::uint32_t cmp)
{
boost::uint32_t oldValue;
boost::uint32_t valueToStore;
do
{
oldValue = lwarxu(mem);
} while (!stwcxu(mem, (oldValue == with) ? cmp : oldValue));
return oldValue;
}
//! Atomically set an boost::uint32_t in memory
//! "mem": pointer to the object
//! "param": val value that the object will assume
inline void atomic_write32(volatile boost::uint32_t *mem, boost::uint32_t val)
{ *mem = val; }
} //namespace ipcdetail
} //namespace interprocess
} //namespace boost
#elif defined(__GNUC__) && ( __GNUC__ * 100 + __GNUC_MINOR__ >= 401 )
namespace boost {
namespace interprocess {
namespace ipcdetail{
//! Atomically add 'val' to an boost::uint32_t
//! "mem": pointer to the object
//! "val": amount to add
//! Returns the old value pointed to by mem
inline boost::uint32_t atomic_add32
(volatile boost::uint32_t *mem, boost::uint32_t val)
{ return __sync_fetch_and_add(const_cast<boost::uint32_t *>(mem), val); }
//! Atomically increment an apr_uint32_t by 1
//! "mem": pointer to the object
//! Returns the old value pointed to by mem
inline boost::uint32_t atomic_inc32(volatile boost::uint32_t *mem)
{ return atomic_add32(mem, 1); }
//! Atomically decrement an boost::uint32_t by 1
//! "mem": pointer to the atomic value
//! Returns the old value pointed to by mem
inline boost::uint32_t atomic_dec32(volatile boost::uint32_t *mem)
{ return atomic_add32(mem, (boost::uint32_t)-1); }
//! Atomically read an boost::uint32_t from memory
inline boost::uint32_t atomic_read32(volatile boost::uint32_t *mem)
{ return *mem; }
//! Compare an boost::uint32_t's value with "cmp".
//! If they are the same swap the value with "with"
//! "mem": pointer to the value
//! "with" what to swap it with
//! "cmp": the value to compare it to
//! Returns the old value of *mem
inline boost::uint32_t atomic_cas32
(volatile boost::uint32_t *mem, boost::uint32_t with, boost::uint32_t cmp)
{ return __sync_val_compare_and_swap(const_cast<boost::uint32_t *>(mem), cmp, with); }
//! Atomically set an boost::uint32_t in memory
//! "mem": pointer to the object
//! "param": val value that the object will assume
inline void atomic_write32(volatile boost::uint32_t *mem, boost::uint32_t val)
{ *mem = val; }
} //namespace ipcdetail{
} //namespace interprocess{
} //namespace boost{
#else
#error No atomic operations implemented for this platform, sorry!
#endif
namespace boost{
namespace interprocess{
namespace ipcdetail{
inline bool atomic_add_unless32
(volatile boost::uint32_t *mem, boost::uint32_t value, boost::uint32_t unless_this)
{
boost::uint32_t old, c(atomic_read32(mem));
while(c != unless_this && (old = atomic_cas32(mem, c + value, c)) != c){
c = old;
}
return c != unless_this;
}
} //namespace ipcdetail
} //namespace interprocess
} //namespace boost
#include <boost/interprocess/detail/config_end.hpp>
#endif //BOOST_INTERPROCESS_DETAIL_ATOMIC_HPP