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concurrentqueue/benchmarks/boost/atomic/detail/ops_gcc_x86_dcas.hpp

617 lines
23 KiB
C++

/*
* 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)
*
* Copyright (c) 2009 Helge Bahmann
* Copyright (c) 2012 Tim Blechmann
* Copyright (c) 2014 Andrey Semashev
*/
/*!
* \file atomic/detail/ops_gcc_x86_dcas.hpp
*
* This header contains implementation of the double-width CAS primitive for x86.
*/
#ifndef BOOST_ATOMIC_DETAIL_OPS_GCC_X86_DCAS_HPP_INCLUDED_
#define BOOST_ATOMIC_DETAIL_OPS_GCC_X86_DCAS_HPP_INCLUDED_
#include <boost/cstdint.hpp>
#include <boost/memory_order.hpp>
#include <boost/atomic/detail/config.hpp>
#include <boost/atomic/detail/storage_type.hpp>
#include <boost/atomic/capabilities.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
#pragma once
#endif
namespace boost {
namespace atomics {
namespace detail {
#if defined(BOOST_ATOMIC_DETAIL_X86_HAS_CMPXCHG8B)
template< bool Signed >
struct gcc_dcas_x86
{
typedef typename make_storage_type< 8u, Signed >::type storage_type;
typedef typename make_storage_type< 8u, Signed >::aligned aligned_storage_type;
static BOOST_FORCEINLINE void store(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
{
if ((((uint32_t)&storage) & 0x00000007) == 0)
{
#if defined(__SSE2__)
__asm__ __volatile__
(
#if defined(__AVX__)
"vmovq %1, %%xmm4\n\t"
"vmovq %%xmm4, %0\n\t"
#else
"movq %1, %%xmm4\n\t"
"movq %%xmm4, %0\n\t"
#endif
: "=m" (storage)
: "m" (v)
: "memory", "xmm4"
);
#else
__asm__ __volatile__
(
"fildll %1\n\t"
"fistpll %0\n\t"
: "=m" (storage)
: "m" (v)
: "memory"
);
#endif
}
else
{
#if !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
#if defined(__PIC__)
uint32_t scratch;
__asm__ __volatile__
(
"movl %%ebx, %[scratch]\n\t"
"movl %[value_lo], %%ebx\n\t"
"movl %[dest], %%eax\n\t"
"movl 4+%[dest], %%edx\n\t"
".align 16\n\t"
"1: lock; cmpxchg8b %[dest]\n\t"
"jne 1b\n\t"
"movl %[scratch], %%ebx\n\t"
: [scratch] "=m" (scratch), [dest] "=o" (storage)
: [value_lo] "a" ((uint32_t)v), "c" ((uint32_t)(v >> 32))
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "edx", "memory"
);
#else // defined(__PIC__)
__asm__ __volatile__
(
"movl %[dest], %%eax\n\t"
"movl 4+%[dest], %%edx\n\t"
".align 16\n\t"
"1: lock; cmpxchg8b %[dest]\n\t"
"jne 1b\n\t"
: [dest] "=o" (storage)
: [value_lo] "b" ((uint32_t)v), "c" ((uint32_t)(v >> 32))
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "eax", "edx", "memory"
);
#endif // defined(__PIC__)
#else // !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
#if defined(__PIC__)
uint32_t scratch;
__asm__ __volatile__
(
"movl %%ebx, %[scratch]\n\t"
"movl %[value_lo], %%ebx\n\t"
"movl 0(%[dest]), %%eax\n\t"
"movl 4(%[dest]), %%edx\n\t"
".align 16\n\t"
"1: lock; cmpxchg8b 0(%[dest])\n\t"
"jne 1b\n\t"
"movl %[scratch], %%ebx\n\t"
#if !defined(BOOST_ATOMIC_DETAIL_NO_ASM_CONSTRAINT_ALTERNATIVES)
: [scratch] "=m,m" (scratch)
: [value_lo] "a,a" ((uint32_t)v), "c,c" ((uint32_t)(v >> 32)), [dest] "D,S" (&storage)
#else
: [scratch] "=m" (scratch)
: [value_lo] "a" ((uint32_t)v), "c" ((uint32_t)(v >> 32)), [dest] "D" (&storage)
#endif
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "edx", "memory"
);
#else // defined(__PIC__)
__asm__ __volatile__
(
"movl 0(%[dest]), %%eax\n\t"
"movl 4(%[dest]), %%edx\n\t"
".align 16\n\t"
"1: lock; cmpxchg8b 0(%[dest])\n\t"
"jne 1b\n\t"
:
#if !defined(BOOST_ATOMIC_DETAIL_NO_ASM_CONSTRAINT_ALTERNATIVES)
: [value_lo] "b,b" ((uint32_t)v), "c,c" ((uint32_t)(v >> 32)), [dest] "D,S" (&storage)
#else
: [value_lo] "b" ((uint32_t)v), "c" ((uint32_t)(v >> 32)), [dest] "D" (&storage)
#endif
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "eax", "edx", "memory"
);
#endif // defined(__PIC__)
#endif // !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
}
}
static BOOST_FORCEINLINE storage_type load(storage_type const volatile& storage, memory_order) BOOST_NOEXCEPT
{
storage_type value;
if ((((uint32_t)&storage) & 0x00000007) == 0)
{
#if defined(__SSE2__)
__asm__ __volatile__
(
#if defined(__AVX__)
"vmovq %1, %%xmm4\n\t"
"vmovq %%xmm4, %0\n\t"
#else
"movq %1, %%xmm4\n\t"
"movq %%xmm4, %0\n\t"
#endif
: "=m" (value)
: "m" (storage)
: "memory", "xmm4"
);
#else
__asm__ __volatile__
(
"fildll %1\n\t"
"fistpll %0\n\t"
: "=m" (value)
: "m" (storage)
: "memory"
);
#endif
}
else
{
#if defined(__clang__)
// Clang cannot allocate eax:edx register pairs but it has sync intrinsics
value = __sync_val_compare_and_swap(&storage, (storage_type)0, (storage_type)0);
#else
// We don't care for comparison result here; the previous value will be stored into value anyway.
// Also we don't care for ebx and ecx values, they just have to be equal to eax and edx before cmpxchg8b.
__asm__ __volatile__
(
"movl %%ebx, %%eax\n\t"
"movl %%ecx, %%edx\n\t"
"lock; cmpxchg8b %[storage]\n\t"
: "=&A" (value)
: [storage] "m" (storage)
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
);
#endif
}
return value;
}
static BOOST_FORCEINLINE bool compare_exchange_strong(
storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order, memory_order) BOOST_NOEXCEPT
{
#if defined(__clang__)
// Clang cannot allocate eax:edx register pairs but it has sync intrinsics
storage_type old_expected = expected;
expected = __sync_val_compare_and_swap(&storage, old_expected, desired);
return expected == old_expected;
#elif defined(__PIC__)
// Make sure ebx is saved and restored properly in case
// of position independent code. To make this work
// setup register constraints such that ebx can not be
// used by accident e.g. as base address for the variable
// to be modified. Accessing "scratch" should always be okay,
// as it can only be placed on the stack (and therefore
// accessed through ebp or esp only).
//
// In theory, could push/pop ebx onto/off the stack, but movs
// to a prepared stack slot turn out to be faster.
uint32_t scratch;
bool success;
__asm__ __volatile__
(
"movl %%ebx, %[scratch]\n\t"
"movl %[desired_lo], %%ebx\n\t"
"lock; cmpxchg8b %[dest]\n\t"
"movl %[scratch], %%ebx\n\t"
"sete %[success]\n\t"
#if !defined(BOOST_ATOMIC_DETAIL_NO_ASM_CONSTRAINT_ALTERNATIVES)
: "+A,A,A,A,A,A" (expected), [dest] "+m,m,m,m,m,m" (storage), [scratch] "=m,m,m,m,m,m" (scratch), [success] "=q,m,q,m,q,m" (success)
: [desired_lo] "S,S,D,D,m,m" ((uint32_t)desired), "c,c,c,c,c,c" ((uint32_t)(desired >> 32))
#else
: "+A" (expected), [dest] "+m" (storage), [scratch] "=m" (scratch), [success] "=q" (success)
: [desired_lo] "S" ((uint32_t)desired), "c" ((uint32_t)(desired >> 32))
#endif
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
);
return success;
#else
bool success;
__asm__ __volatile__
(
"lock; cmpxchg8b %[dest]\n\t"
"sete %[success]\n\t"
#if !defined(BOOST_ATOMIC_DETAIL_NO_ASM_CONSTRAINT_ALTERNATIVES)
: "+A,A" (expected), [dest] "+m,m" (storage), [success] "=q,m" (success)
: "b,b" ((uint32_t)desired), "c,c" ((uint32_t)(desired >> 32))
#else
: "+A" (expected), [dest] "+m" (storage), [success] "=q" (success)
: "b" ((uint32_t)desired), "c" ((uint32_t)(desired >> 32))
#endif
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
);
return success;
#endif
}
static BOOST_FORCEINLINE bool compare_exchange_weak(
storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order success_order, memory_order failure_order) BOOST_NOEXCEPT
{
return compare_exchange_strong(storage, expected, desired, success_order, failure_order);
}
static BOOST_FORCEINLINE storage_type exchange(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
#if defined(__clang__)
// Clang cannot allocate eax:edx register pairs but it has sync intrinsics
storage_type old_val = storage;
while (true)
{
storage_type val = __sync_val_compare_and_swap(&storage, old_val, v);
if (val == old_val)
return val;
old_val = val;
}
#elif !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
#if defined(__PIC__)
uint32_t scratch;
__asm__ __volatile__
(
"movl %%ebx, %[scratch]\n\t"
"movl %%eax, %%ebx\n\t"
"movl %%edx, %%ecx\n\t"
"movl %[dest], %%eax\n\t"
"movl 4+%[dest], %%edx\n\t"
".align 16\n\t"
"1: lock; cmpxchg8b %[dest]\n\t"
"jne 1b\n\t"
"movl %[scratch], %%ebx\n\t"
: "+A" (v), [scratch] "=m" (scratch), [dest] "+o" (storage)
:
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "ecx", "memory"
);
return v;
#else // defined(__PIC__)
__asm__ __volatile__
(
"movl %[dest], %%eax\n\t"
"movl 4+%[dest], %%edx\n\t"
".align 16\n\t"
"1: lock; cmpxchg8b %[dest]\n\t"
"jne 1b\n\t"
: "=A" (v), [dest] "+o" (storage)
: "b" ((uint32_t)v), "c" ((uint32_t)(v >> 32))
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
);
return v;
#endif // defined(__PIC__)
#else // !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
#if defined(__PIC__)
uint32_t scratch;
__asm__ __volatile__
(
"movl %%ebx, %[scratch]\n\t"
"movl %%eax, %%ebx\n\t"
"movl %%edx, %%ecx\n\t"
"movl 0(%[dest]), %%eax\n\t"
"movl 4(%[dest]), %%edx\n\t"
".align 16\n\t"
"1: lock; cmpxchg8b 0(%[dest])\n\t"
"jne 1b\n\t"
"movl %[scratch], %%ebx\n\t"
#if !defined(BOOST_ATOMIC_DETAIL_NO_ASM_CONSTRAINT_ALTERNATIVES)
: "+A,A" (v), [scratch] "=m,m" (scratch)
: [dest] "D,S" (&storage)
#else
: "+A" (v), [scratch] "=m" (scratch)
: [dest] "D" (&storage)
#endif
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "ecx", "memory"
);
return v;
#else // defined(__PIC__)
__asm__ __volatile__
(
"movl 0(%[dest]), %%eax\n\t"
"movl 4(%[dest]), %%edx\n\t"
".align 16\n\t"
"1: lock; cmpxchg8b 0(%[dest])\n\t"
"jne 1b\n\t"
#if !defined(BOOST_ATOMIC_DETAIL_NO_ASM_CONSTRAINT_ALTERNATIVES)
: "=A,A" (v)
: "b,b" ((uint32_t)v), "c,c" ((uint32_t)(v >> 32)), [dest] "D,S" (&storage)
#else
: "=A" (v)
: "b" ((uint32_t)v), "c" ((uint32_t)(v >> 32)), [dest] "D" (&storage)
#endif
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
);
return v;
#endif // defined(__PIC__)
#endif
}
static BOOST_FORCEINLINE bool is_lock_free(storage_type const volatile&) BOOST_NOEXCEPT
{
return true;
}
};
#endif // defined(BOOST_ATOMIC_DETAIL_X86_HAS_CMPXCHG8B)
#if defined(BOOST_ATOMIC_DETAIL_X86_HAS_CMPXCHG16B)
template< bool Signed >
struct gcc_dcas_x86_64
{
typedef typename make_storage_type< 16u, Signed >::type storage_type;
typedef typename make_storage_type< 16u, Signed >::aligned aligned_storage_type;
static BOOST_FORCEINLINE void store(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
{
uint64_t const* p_value = (uint64_t const*)&v;
#if !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
__asm__ __volatile__
(
"movq %[dest], %%rax\n\t"
"movq 8+%[dest], %%rdx\n\t"
".align 16\n\t"
"1: lock; cmpxchg16b %[dest]\n\t"
"jne 1b\n\t"
: [dest] "=o" (storage)
: "b" (p_value[0]), "c" (p_value[1])
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "rax", "rdx", "memory"
);
#else // !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
__asm__ __volatile__
(
"movq 0(%[dest]), %%rax\n\t"
"movq 8(%[dest]), %%rdx\n\t"
".align 16\n\t"
"1: lock; cmpxchg16b 0(%[dest])\n\t"
"jne 1b\n\t"
:
: "b" (p_value[0]), "c" (p_value[1]), [dest] "r" (&storage)
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "rax", "rdx", "memory"
);
#endif // !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
}
static BOOST_FORCEINLINE storage_type load(storage_type const volatile& storage, memory_order) BOOST_NOEXCEPT
{
#if defined(__clang__)
// Clang cannot allocate rax:rdx register pairs but it has sync intrinsics
storage_type value = storage_type();
return __sync_val_compare_and_swap(&storage, value, value);
#elif defined(BOOST_ATOMIC_DETAIL_NO_ASM_RAX_RDX_PAIRS)
// GCC 4.4 can't allocate rax:rdx register pair either but it also doesn't support 128-bit __sync_val_compare_and_swap
storage_type value;
// We don't care for comparison result here; the previous value will be stored into value anyway.
// Also we don't care for rbx and rcx values, they just have to be equal to rax and rdx before cmpxchg16b.
#if !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
__asm__ __volatile__
(
"movq %%rbx, %%rax\n\t"
"movq %%rcx, %%rdx\n\t"
"lock; cmpxchg16b %[storage]\n\t"
"movq %%rax, %[value]\n\t"
"movq %%rdx, 8+%[value]\n\t"
: [value] "=o" (value)
: [storage] "m" (storage)
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory", "rax", "rdx"
);
#else // !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
__asm__ __volatile__
(
"movq %%rbx, %%rax\n\t"
"movq %%rcx, %%rdx\n\t"
"lock; cmpxchg16b %[storage]\n\t"
"movq %%rax, 0(%[value])\n\t"
"movq %%rdx, 8(%[value])\n\t"
:
: [storage] "m" (storage), [value] "r" (&value)
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory", "rax", "rdx"
);
#endif // !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
return value;
#else // defined(BOOST_ATOMIC_DETAIL_NO_ASM_RAX_RDX_PAIRS)
storage_type value;
// We don't care for comparison result here; the previous value will be stored into value anyway.
// Also we don't care for rbx and rcx values, they just have to be equal to rax and rdx before cmpxchg16b.
__asm__ __volatile__
(
"movq %%rbx, %%rax\n\t"
"movq %%rcx, %%rdx\n\t"
"lock; cmpxchg16b %[storage]\n\t"
: "=&A" (value)
: [storage] "m" (storage)
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
);
return value;
#endif
}
static BOOST_FORCEINLINE bool compare_exchange_strong(
storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order, memory_order) BOOST_NOEXCEPT
{
#if defined(__clang__)
// Clang cannot allocate rax:rdx register pairs but it has sync intrinsics
storage_type old_expected = expected;
expected = __sync_val_compare_and_swap(&storage, old_expected, desired);
return expected == old_expected;
#elif defined(BOOST_ATOMIC_DETAIL_NO_ASM_RAX_RDX_PAIRS)
// GCC 4.4 can't allocate rax:rdx register pair either but it also doesn't support 128-bit __sync_val_compare_and_swap
uint64_t const* p_desired = (uint64_t const*)&desired;
bool success;
#if !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
__asm__ __volatile__
(
"movq %[expected], %%rax\n\t"
"movq 8+%[expected], %%rdx\n\t"
"lock; cmpxchg16b %[dest]\n\t"
"sete %[success]\n\t"
"movq %%rax, %[expected]\n\t"
"movq %%rdx, 8+%[expected]\n\t"
: [dest] "+m" (storage), [expected] "+o" (expected), [success] "=q" (success)
: "b" (p_desired[0]), "c" (p_desired[1])
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory", "rax", "rdx"
);
#else // !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
__asm__ __volatile__
(
"movq 0(%[expected]), %%rax\n\t"
"movq 8(%[expected]), %%rdx\n\t"
"lock; cmpxchg16b %[dest]\n\t"
"sete %[success]\n\t"
"movq %%rax, 0(%[expected])\n\t"
"movq %%rdx, 8(%[expected])\n\t"
: [dest] "+m" (storage), [success] "=q" (success)
: "b" (p_desired[0]), "c" (p_desired[1]), [expected] "r" (&expected)
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory", "rax", "rdx"
);
#endif // !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
return success;
#else // defined(BOOST_ATOMIC_DETAIL_NO_ASM_RAX_RDX_PAIRS)
uint64_t const* p_desired = (uint64_t const*)&desired;
bool success;
__asm__ __volatile__
(
"lock; cmpxchg16b %[dest]\n\t"
"sete %[success]\n\t"
#if !defined(BOOST_ATOMIC_DETAIL_NO_ASM_CONSTRAINT_ALTERNATIVES)
: "+A,A" (expected), [dest] "+m,m" (storage), [success] "=q,m" (success)
: "b,b" (p_desired[0]), "c,c" (p_desired[1])
#else
: "+A" (expected), [dest] "+m" (storage), [success] "=q" (success)
: "b" (p_desired[0]), "c" (p_desired[1])
#endif
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
);
return success;
#endif
}
static BOOST_FORCEINLINE bool compare_exchange_weak(
storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order success_order, memory_order failure_order) BOOST_NOEXCEPT
{
return compare_exchange_strong(storage, expected, desired, success_order, failure_order);
}
static BOOST_FORCEINLINE storage_type exchange(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
#if defined(__clang__)
// Clang cannot allocate eax:edx register pairs but it has sync intrinsics
storage_type old_val = storage;
while (true)
{
storage_type val = __sync_val_compare_and_swap(&storage, old_val, v);
if (val == old_val)
return val;
old_val = val;
}
#elif defined(BOOST_ATOMIC_DETAIL_NO_ASM_RAX_RDX_PAIRS)
// GCC 4.4 can't allocate rax:rdx register pair either but it also doesn't support 128-bit __sync_val_compare_and_swap
storage_type old_value;
uint64_t const* p_value = (uint64_t const*)&v;
#if !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
__asm__ __volatile__
(
"movq %[dest], %%rax\n\t"
"movq 8+%[dest], %%rdx\n\t"
".align 16\n\t"
"1: lock; cmpxchg16b %[dest]\n\t"
"jne 1b\n\t"
"movq %%rax, %[old_value]\n\t"
"movq %%rdx, 8+%[old_value]\n\t"
: [dest] "+o" (storage), [old_value] "=o" (old_value)
: "b" (p_value[0]), "c" (p_value[1])
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory", "rax", "rdx"
);
#else // !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
__asm__ __volatile__
(
"movq 0(%[dest]), %%rax\n\t"
"movq 8(%[dest]), %%rdx\n\t"
".align 16\n\t"
"1: lock; cmpxchg16b 0(%[dest])\n\t"
"jne 1b\n\t"
"movq %%rax, 0(%[old_value])\n\t"
"movq %%rdx, 8(%[old_value])\n\t"
:
: "b" (p_value[0]), "c" (p_value[1]), [dest] "r" (&storage), [old_value] "r" (&old_value)
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory", "rax", "rdx"
);
#endif // !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
return old_value;
#else // defined(BOOST_ATOMIC_DETAIL_NO_ASM_RAX_RDX_PAIRS)
uint64_t const* p_value = (uint64_t const*)&v;
#if !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
__asm__ __volatile__
(
"movq %[dest], %%rax\n\t"
"movq 8+%[dest], %%rdx\n\t"
".align 16\n\t"
"1: lock; cmpxchg16b %[dest]\n\t"
"jne 1b\n\t"
: "=&A" (v), [dest] "+o" (storage)
: "b" (p_value[0]), "c" (p_value[1])
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
);
#else // !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
__asm__ __volatile__
(
"movq 0(%[dest]), %%rax\n\t"
"movq 8(%[dest]), %%rdx\n\t"
".align 16\n\t"
"1: lock; cmpxchg16b 0(%[dest])\n\t"
"jne 1b\n\t"
: "=&A" (v)
: "b" (p_value[0]), "c" (p_value[1]), [dest] "r" (&storage)
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
);
#endif // !defined(BOOST_ATOMIC_DETAIL_NO_ASM_IMPLIED_ZERO_DISPLACEMENTS)
return v;
#endif
}
static BOOST_FORCEINLINE bool is_lock_free(storage_type const volatile&) BOOST_NOEXCEPT
{
return true;
}
};
#endif // defined(BOOST_ATOMIC_DETAIL_X86_HAS_CMPXCHG16B)
} // namespace detail
} // namespace atomics
} // namespace boost
#endif // BOOST_ATOMIC_DETAIL_OPS_GCC_X86_DCAS_HPP_INCLUDED_