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ext-boost/boost/atomic/detail/ops_gcc_arm.hpp

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externals: Update boost to 1.72 and add Boost Context
2020-02-10 16:31:57 +00:00
/*
* 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) 2013 Tim Blechmann
* Copyright (c) 2014 Andrey Semashev
*/
/*!
* \file atomic/detail/ops_gcc_arm.hpp
*
* This header contains implementation of the \c operations template.
*/
#ifndef BOOST_ATOMIC_DETAIL_OPS_GCC_ARM_HPP_INCLUDED_
#define BOOST_ATOMIC_DETAIL_OPS_GCC_ARM_HPP_INCLUDED_
#include <cstddef>
#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/detail/integral_extend.hpp>
#include <boost/atomic/detail/operations_fwd.hpp>
#include <boost/atomic/detail/ops_gcc_arm_common.hpp>
#include <boost/atomic/capabilities.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
#pragma once
#endif
namespace boost {
namespace atomics {
namespace detail {
// From the ARM Architecture Reference Manual for architecture v6:
//
// LDREX{<cond>} <Rd>, [<Rn>]
// <Rd> Specifies the destination register for the memory word addressed by <Rd>
// <Rn> Specifies the register containing the address.
//
// STREX{<cond>} <Rd>, <Rm>, [<Rn>]
// <Rd> Specifies the destination register for the returned status value.
// 0 if the operation updates memory
// 1 if the operation fails to update memory
// <Rm> Specifies the register containing the word to be stored to memory.
// <Rn> Specifies the register containing the address.
// Rd must not be the same register as Rm or Rn.
//
// ARM v7 is like ARM v6 plus:
// There are half-word and byte versions of the LDREX and STREX instructions,
// LDREXH, LDREXB, STREXH and STREXB.
// There are also double-word versions, LDREXD and STREXD.
// (Actually it looks like these are available from version 6k onwards.)
// FIXME these are not yet used; should be mostly a matter of copy-and-paste.
// I think you can supply an immediate offset to the address.
template< bool Signed >
struct operations< 4u, Signed > :
public gcc_arm_operations_base
{
typedef typename make_storage_type< 4u >::type storage_type;
typedef typename make_storage_type< 4u >::aligned aligned_storage_type;
static BOOST_CONSTEXPR_OR_CONST std::size_t storage_size = 4u;
static BOOST_CONSTEXPR_OR_CONST bool is_signed = Signed;
static BOOST_FORCEINLINE void store(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
storage = v;
fence_after_store(order);
}
static BOOST_FORCEINLINE storage_type load(storage_type const volatile& storage, memory_order order) BOOST_NOEXCEPT
{
storage_type v = storage;
fence_after(order);
return v;
}
static BOOST_FORCEINLINE storage_type exchange(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
storage_type original;
fence_before(order);
uint32_t tmp;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrex %[original], %[storage]\n" // load the original value
"strex %[tmp], %[value], %[storage]\n" // store the replacement, tmp = store failed
"teq %[tmp], #0\n" // check if store succeeded
"bne 1b\n"
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [tmp] "=&l" (tmp), [original] "=&r" (original), [storage] "+Q" (storage)
: [value] "r" (v)
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return original;
}
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
{
fence_before(success_order);
uint32_t success;
uint32_t tmp;
storage_type original;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"mov %[success], #0\n" // success = 0
"ldrex %[original], %[storage]\n" // original = *(&storage)
"cmp %[original], %[expected]\n" // flags = original==expected
"itt eq\n" // [hint that the following 2 instructions are conditional on flags.equal]
"strexeq %[success], %[desired], %[storage]\n" // if (flags.equal) *(&storage) = desired, success = store failed
"eoreq %[success], %[success], #1\n" // if (flags.equal) success ^= 1 (i.e. make it 1 if store succeeded)
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[success] "=&r" (success), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [expected] "Ir" (expected), // %4
[desired] "r" (desired) // %5
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
if (success)
fence_after(success_order);
else
fence_after(failure_order);
expected = original;
return !!success;
}
static BOOST_FORCEINLINE bool compare_exchange_strong(
storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order success_order, memory_order failure_order) BOOST_NOEXCEPT
{
fence_before(success_order);
uint32_t success;
uint32_t tmp;
storage_type original;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"mov %[success], #0\n" // success = 0
"1:\n"
"ldrex %[original], %[storage]\n" // original = *(&storage)
"cmp %[original], %[expected]\n" // flags = original==expected
"bne 2f\n" // if (!flags.equal) goto end
"strex %[success], %[desired], %[storage]\n" // *(&storage) = desired, success = store failed
"eors %[success], %[success], #1\n" // success ^= 1 (i.e. make it 1 if store succeeded); flags.equal = success == 0
"beq 1b\n" // if (flags.equal) goto retry
"2:\n"
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[success] "=&r" (success), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [expected] "Ir" (expected), // %4
[desired] "r" (desired) // %5
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
if (success)
fence_after(success_order);
else
fence_after(failure_order);
expected = original;
return !!success;
}
static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrex %[original], %[storage]\n" // original = *(&storage)
"add %[result], %[original], %[value]\n" // result = original + value
"strex %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return original;
}
static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrex %[original], %[storage]\n" // original = *(&storage)
"sub %[result], %[original], %[value]\n" // result = original - value
"strex %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return original;
}
static BOOST_FORCEINLINE storage_type fetch_and(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrex %[original], %[storage]\n" // original = *(&storage)
"and %[result], %[original], %[value]\n" // result = original & value
"strex %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return original;
}
static BOOST_FORCEINLINE storage_type fetch_or(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrex %[original], %[storage]\n" // original = *(&storage)
"orr %[result], %[original], %[value]\n" // result = original | value
"strex %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return original;
}
static BOOST_FORCEINLINE storage_type fetch_xor(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrex %[original], %[storage]\n" // original = *(&storage)
"eor %[result], %[original], %[value]\n" // result = original ^ value
"strex %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return original;
}
static BOOST_FORCEINLINE bool test_and_set(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
{
return !!exchange(storage, (storage_type)1, order);
}
static BOOST_FORCEINLINE void clear(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
{
store(storage, 0, order);
}
};
#if defined(BOOST_ATOMIC_DETAIL_ARM_HAS_LDREXB_STREXB)
template< bool Signed >
struct operations< 1u, Signed > :
public gcc_arm_operations_base
{
typedef typename make_storage_type< 1u >::type storage_type;
typedef typename make_storage_type< 1u >::aligned aligned_storage_type;
typedef typename make_storage_type< 4u >::type extended_storage_type;
static BOOST_CONSTEXPR_OR_CONST std::size_t storage_size = 1u;
static BOOST_CONSTEXPR_OR_CONST bool is_signed = Signed;
static BOOST_FORCEINLINE void store(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
storage = v;
fence_after_store(order);
}
static BOOST_FORCEINLINE storage_type load(storage_type const volatile& storage, memory_order order) BOOST_NOEXCEPT
{
storage_type v = storage;
fence_after(order);
return v;
}
static BOOST_FORCEINLINE storage_type exchange(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
extended_storage_type original;
fence_before(order);
uint32_t tmp;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrexb %[original], %[storage]\n" // load the original value and zero-extend to 32 bits
"strexb %[tmp], %[value], %[storage]\n" // store the replacement, tmp = store failed
"teq %[tmp], #0\n" // check if store succeeded
"bne 1b\n"
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [tmp] "=&l" (tmp), [original] "=&r" (original), [storage] "+Q" (storage)
: [value] "r" (v)
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return static_cast< storage_type >(original);
}
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
{
fence_before(success_order);
uint32_t success;
uint32_t tmp;
extended_storage_type original;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"mov %[success], #0\n" // success = 0
"ldrexb %[original], %[storage]\n" // original = zero_extend(*(&storage))
"cmp %[original], %[expected]\n" // flags = original==expected
"itt eq\n" // [hint that the following 2 instructions are conditional on flags.equal]
"strexbeq %[success], %[desired], %[storage]\n" // if (flags.equal) *(&storage) = desired, success = store failed
"eoreq %[success], %[success], #1\n" // if (flags.equal) success ^= 1 (i.e. make it 1 if store succeeded)
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[success] "=&r" (success), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [expected] "Ir" (atomics::detail::zero_extend< extended_storage_type >(expected)), // %4
[desired] "r" (desired) // %5
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
if (success)
fence_after(success_order);
else
fence_after(failure_order);
expected = static_cast< storage_type >(original);
return !!success;
}
static BOOST_FORCEINLINE bool compare_exchange_strong(
storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order success_order, memory_order failure_order) BOOST_NOEXCEPT
{
fence_before(success_order);
uint32_t success;
uint32_t tmp;
extended_storage_type original;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"mov %[success], #0\n" // success = 0
"1:\n"
"ldrexb %[original], %[storage]\n" // original = zero_extend(*(&storage))
"cmp %[original], %[expected]\n" // flags = original==expected
"bne 2f\n" // if (!flags.equal) goto end
"strexb %[success], %[desired], %[storage]\n" // *(&storage) = desired, success = store failed
"eors %[success], %[success], #1\n" // success ^= 1 (i.e. make it 1 if store succeeded); flags.equal = success == 0
"beq 1b\n" // if (flags.equal) goto retry
"2:\n"
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[success] "=&r" (success), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [expected] "Ir" (atomics::detail::zero_extend< extended_storage_type >(expected)), // %4
[desired] "r" (desired) // %5
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
if (success)
fence_after(success_order);
else
fence_after(failure_order);
expected = static_cast< storage_type >(original);
return !!success;
}
static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
extended_storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrexb %[original], %[storage]\n" // original = zero_extend(*(&storage))
"add %[result], %[original], %[value]\n" // result = original + value
"strexb %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return static_cast< storage_type >(original);
}
static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
extended_storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrexb %[original], %[storage]\n" // original = zero_extend(*(&storage))
"sub %[result], %[original], %[value]\n" // result = original - value
"strexb %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return static_cast< storage_type >(original);
}
static BOOST_FORCEINLINE storage_type fetch_and(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
extended_storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrexb %[original], %[storage]\n" // original = zero_extend(*(&storage))
"and %[result], %[original], %[value]\n" // result = original & value
"strexb %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return static_cast< storage_type >(original);
}
static BOOST_FORCEINLINE storage_type fetch_or(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
extended_storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrexb %[original], %[storage]\n" // original = zero_extend(*(&storage))
"orr %[result], %[original], %[value]\n" // result = original | value
"strexb %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return static_cast< storage_type >(original);
}
static BOOST_FORCEINLINE storage_type fetch_xor(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
extended_storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrexb %[original], %[storage]\n" // original = zero_extend(*(&storage))
"eor %[result], %[original], %[value]\n" // result = original ^ value
"strexb %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return static_cast< storage_type >(original);
}
static BOOST_FORCEINLINE bool test_and_set(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
{
return !!exchange(storage, (storage_type)1, order);
}
static BOOST_FORCEINLINE void clear(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
{
store(storage, 0, order);
}
};
#else // defined(BOOST_ATOMIC_DETAIL_ARM_HAS_LDREXB_STREXB)
template< >
struct operations< 1u, false > :
public operations< 4u, false >
{
typedef operations< 4u, false > base_type;
typedef base_type::storage_type storage_type;
static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrex %[original], %[storage]\n" // original = *(&storage)
"add %[result], %[original], %[value]\n" // result = original + value
"uxtb %[result], %[result]\n" // zero extend result from 8 to 32 bits
"strex %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return original;
}
static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrex %[original], %[storage]\n" // original = *(&storage)
"sub %[result], %[original], %[value]\n" // result = original - value
"uxtb %[result], %[result]\n" // zero extend result from 8 to 32 bits
"strex %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return original;
}
};
template< >
struct operations< 1u, true > :
public operations< 4u, true >
{
typedef operations< 4u, true > base_type;
typedef base_type::storage_type storage_type;
static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrex %[original], %[storage]\n" // original = *(&storage)
"add %[result], %[original], %[value]\n" // result = original + value
"sxtb %[result], %[result]\n" // sign extend result from 8 to 32 bits
"strex %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return original;
}
static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrex %[original], %[storage]\n" // original = *(&storage)
"sub %[result], %[original], %[value]\n" // result = original - value
"sxtb %[result], %[result]\n" // sign extend result from 8 to 32 bits
"strex %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return original;
}
};
#endif // defined(BOOST_ATOMIC_DETAIL_ARM_HAS_LDREXB_STREXB)
#if defined(BOOST_ATOMIC_DETAIL_ARM_HAS_LDREXH_STREXH)
template< bool Signed >
struct operations< 2u, Signed > :
public gcc_arm_operations_base
{
typedef typename make_storage_type< 2u >::type storage_type;
typedef typename make_storage_type< 2u >::aligned aligned_storage_type;
typedef typename make_storage_type< 4u >::type extended_storage_type;
static BOOST_CONSTEXPR_OR_CONST std::size_t storage_size = 2u;
static BOOST_CONSTEXPR_OR_CONST bool is_signed = Signed;
static BOOST_FORCEINLINE void store(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
storage = v;
fence_after_store(order);
}
static BOOST_FORCEINLINE storage_type load(storage_type const volatile& storage, memory_order order) BOOST_NOEXCEPT
{
storage_type v = storage;
fence_after(order);
return v;
}
static BOOST_FORCEINLINE storage_type exchange(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
extended_storage_type original;
fence_before(order);
uint32_t tmp;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrexh %[original], %[storage]\n" // load the original value and zero-extend to 32 bits
"strexh %[tmp], %[value], %[storage]\n" // store the replacement, tmp = store failed
"teq %[tmp], #0\n" // check if store succeeded
"bne 1b\n"
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [tmp] "=&l" (tmp), [original] "=&r" (original), [storage] "+Q" (storage)
: [value] "r" (v)
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return static_cast< storage_type >(original);
}
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
{
fence_before(success_order);
uint32_t success;
uint32_t tmp;
extended_storage_type original;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"mov %[success], #0\n" // success = 0
"ldrexh %[original], %[storage]\n" // original = zero_extend(*(&storage))
"cmp %[original], %[expected]\n" // flags = original==expected
"itt eq\n" // [hint that the following 2 instructions are conditional on flags.equal]
"strexheq %[success], %[desired], %[storage]\n" // if (flags.equal) *(&storage) = desired, success = store failed
"eoreq %[success], %[success], #1\n" // if (flags.equal) success ^= 1 (i.e. make it 1 if store succeeded)
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[success] "=&r" (success), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [expected] "Ir" (atomics::detail::zero_extend< extended_storage_type >(expected)), // %4
[desired] "r" (desired) // %5
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
if (success)
fence_after(success_order);
else
fence_after(failure_order);
expected = static_cast< storage_type >(original);
return !!success;
}
static BOOST_FORCEINLINE bool compare_exchange_strong(
storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order success_order, memory_order failure_order) BOOST_NOEXCEPT
{
fence_before(success_order);
uint32_t success;
uint32_t tmp;
extended_storage_type original;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"mov %[success], #0\n" // success = 0
"1:\n"
"ldrexh %[original], %[storage]\n" // original = zero_extend(*(&storage))
"cmp %[original], %[expected]\n" // flags = original==expected
"bne 2f\n" // if (!flags.equal) goto end
"strexh %[success], %[desired], %[storage]\n" // *(&storage) = desired, success = store failed
"eors %[success], %[success], #1\n" // success ^= 1 (i.e. make it 1 if store succeeded); flags.equal = success == 0
"beq 1b\n" // if (flags.equal) goto retry
"2:\n"
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[success] "=&r" (success), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [expected] "Ir" (atomics::detail::zero_extend< extended_storage_type >(expected)), // %4
[desired] "r" (desired) // %5
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
if (success)
fence_after(success_order);
else
fence_after(failure_order);
expected = static_cast< storage_type >(original);
return !!success;
}
static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
extended_storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrexh %[original], %[storage]\n" // original = zero_extend(*(&storage))
"add %[result], %[original], %[value]\n" // result = original + value
"strexh %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return static_cast< storage_type >(original);
}
static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
extended_storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrexh %[original], %[storage]\n" // original = zero_extend(*(&storage))
"sub %[result], %[original], %[value]\n" // result = original - value
"strexh %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return static_cast< storage_type >(original);
}
static BOOST_FORCEINLINE storage_type fetch_and(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
extended_storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrexh %[original], %[storage]\n" // original = zero_extend(*(&storage))
"and %[result], %[original], %[value]\n" // result = original & value
"strexh %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return static_cast< storage_type >(original);
}
static BOOST_FORCEINLINE storage_type fetch_or(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
extended_storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrexh %[original], %[storage]\n" // original = zero_extend(*(&storage))
"orr %[result], %[original], %[value]\n" // result = original | value
"strexh %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return static_cast< storage_type >(original);
}
static BOOST_FORCEINLINE storage_type fetch_xor(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
extended_storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrexh %[original], %[storage]\n" // original = zero_extend(*(&storage))
"eor %[result], %[original], %[value]\n" // result = original ^ value
"strexh %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return static_cast< storage_type >(original);
}
static BOOST_FORCEINLINE bool test_and_set(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
{
return !!exchange(storage, (storage_type)1, order);
}
static BOOST_FORCEINLINE void clear(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
{
store(storage, 0, order);
}
};
#else // defined(BOOST_ATOMIC_DETAIL_ARM_HAS_LDREXH_STREXH)
template< >
struct operations< 2u, false > :
public operations< 4u, false >
{
typedef operations< 4u, false > base_type;
typedef base_type::storage_type storage_type;
static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrex %[original], %[storage]\n" // original = *(&storage)
"add %[result], %[original], %[value]\n" // result = original + value
"uxth %[result], %[result]\n" // zero extend result from 16 to 32 bits
"strex %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return original;
}
static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrex %[original], %[storage]\n" // original = *(&storage)
"sub %[result], %[original], %[value]\n" // result = original - value
"uxth %[result], %[result]\n" // zero extend result from 16 to 32 bits
"strex %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return original;
}
};
template< >
struct operations< 2u, true > :
public operations< 4u, true >
{
typedef operations< 4u, true > base_type;
typedef base_type::storage_type storage_type;
static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrex %[original], %[storage]\n" // original = *(&storage)
"add %[result], %[original], %[value]\n" // result = original + value
"sxth %[result], %[result]\n" // sign extend result from 16 to 32 bits
"strex %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return original;
}
static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
uint32_t tmp;
storage_type original, result;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%[tmp])
"1:\n"
"ldrex %[original], %[storage]\n" // original = *(&storage)
"sub %[result], %[original], %[value]\n" // result = original - value
"sxth %[result], %[result]\n" // sign extend result from 16 to 32 bits
"strex %[tmp], %[result], %[storage]\n" // *(&storage) = result, tmp = store failed
"teq %[tmp], #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%[tmp])
: [original] "=&r" (original), // %0
[result] "=&r" (result), // %1
[tmp] "=&l" (tmp), // %2
[storage] "+Q" (storage) // %3
: [value] "Ir" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC
);
fence_after(order);
return original;
}
};
#endif // defined(BOOST_ATOMIC_DETAIL_ARM_HAS_LDREXH_STREXH)
#if defined(BOOST_ATOMIC_DETAIL_ARM_HAS_LDREXD_STREXD)
// Unlike 32-bit operations, for 64-bit loads and stores we must use ldrexd/strexd.
// Any other instructions result in a non-atomic sequence of 32-bit accesses.
// See "ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition",
// Section A3.5.3 "Atomicity in the ARM architecture".
// In the asm blocks below we have to use 32-bit register pairs to compose 64-bit values.
// In order to pass the 64-bit operands to/from asm blocks, we use undocumented gcc feature:
// the lower half (Rt) of the operand is accessible normally, via the numbered placeholder (e.g. %0),
// and the upper half (Rt2) - via the same placeholder with an 'H' after the '%' sign (e.g. %H0).
// See: http://hardwarebug.org/2010/07/06/arm-inline-asm-secrets/
template< bool Signed >
struct operations< 8u, Signed > :
public gcc_arm_operations_base
{
typedef typename make_storage_type< 8u >::type storage_type;
typedef typename make_storage_type< 8u >::aligned aligned_storage_type;
static BOOST_CONSTEXPR_OR_CONST std::size_t storage_size = 8u;
static BOOST_CONSTEXPR_OR_CONST bool is_signed = Signed;
static BOOST_FORCEINLINE void store(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
exchange(storage, v, order);
}
static BOOST_FORCEINLINE storage_type load(storage_type const volatile& storage, memory_order order) BOOST_NOEXCEPT
{
storage_type original;
uint32_t tmp;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%0)
"ldrexd %1, %H1, [%2]\n"
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%0)
: BOOST_ATOMIC_DETAIL_ARM_ASM_TMPREG_CONSTRAINT(tmp), // %0
"=&r" (original) // %1
: "r" (&storage) // %2
);
fence_after(order);
return original;
}
static BOOST_FORCEINLINE storage_type exchange(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
storage_type original;
fence_before(order);
uint32_t tmp;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%0)
"1:\n"
"ldrexd %1, %H1, [%3]\n" // load the original value
"strexd %0, %2, %H2, [%3]\n" // store the replacement, tmp = store failed
"teq %0, #0\n" // check if store succeeded
"bne 1b\n"
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%0)
: BOOST_ATOMIC_DETAIL_ARM_ASM_TMPREG_CONSTRAINT(tmp), // %0
"=&r" (original) // %1
: "r" (v), // %2
"r" (&storage) // %3
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
);
fence_after(order);
return original;
}
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
{
fence_before(success_order);
uint32_t tmp;
storage_type original, old_val = expected;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%0)
"ldrexd %1, %H1, [%3]\n" // original = *(&storage)
"cmp %1, %2\n" // flags = original.lo==old_val.lo
"ittt eq\n" // [hint that the following 3 instructions are conditional on flags.equal]
"cmpeq %H1, %H2\n" // if (flags.equal) flags = original.hi==old_val.hi
"strexdeq %0, %4, %H4, [%3]\n" // if (flags.equal) *(&storage) = desired, tmp = store failed
"teqeq %0, #0\n" // if (flags.equal) flags = tmp==0
"ite eq\n" // [hint that the following 2 instructions are conditional on flags.equal]
"moveq %2, #1\n" // if (flags.equal) old_val.lo = 1
"movne %2, #0\n" // if (!flags.equal) old_val.lo = 0
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%0)
: BOOST_ATOMIC_DETAIL_ARM_ASM_TMPREG_CONSTRAINT(tmp), // %0
"=&r" (original), // %1
"+r" (old_val) // %2
: "r" (&storage), // %3
"r" (desired) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
);
const uint32_t success = (uint32_t)old_val;
if (success)
fence_after(success_order);
else
fence_after(failure_order);
expected = original;
return !!success;
}
static BOOST_FORCEINLINE bool compare_exchange_strong(
storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order success_order, memory_order failure_order) BOOST_NOEXCEPT
{
fence_before(success_order);
uint32_t tmp;
storage_type original, old_val = expected;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%0)
"1:\n"
"ldrexd %1, %H1, [%3]\n" // original = *(&storage)
"cmp %1, %2\n" // flags = original.lo==old_val.lo
"it eq\n" // [hint that the following instruction is conditional on flags.equal]
"cmpeq %H1, %H2\n" // if (flags.equal) flags = original.hi==old_val.hi
"bne 2f\n" // if (!flags.equal) goto end
"strexd %0, %4, %H4, [%3]\n" // *(&storage) = desired, tmp = store failed
"teq %0, #0\n" // flags.equal = tmp == 0
"bne 1b\n" // if (flags.equal) goto retry
"2:\n"
"ite eq\n" // [hint that the following 2 instructions are conditional on flags.equal]
"moveq %2, #1\n" // if (flags.equal) old_val.lo = 1
"movne %2, #0\n" // if (!flags.equal) old_val.lo = 0
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%0)
: BOOST_ATOMIC_DETAIL_ARM_ASM_TMPREG_CONSTRAINT(tmp), // %0
"=&r" (original), // %1
"+r" (old_val) // %2
: "r" (&storage), // %3
"r" (desired) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
);
const uint32_t success = (uint32_t)old_val;
if (success)
fence_after(success_order);
else
fence_after(failure_order);
expected = original;
return !!success;
}
static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
storage_type original, result;
uint32_t tmp;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%0)
"1:\n"
"ldrexd %1, %H1, [%3]\n" // original = *(&storage)
"adds %2, %1, %4\n" // result = original + value
"adc %H2, %H1, %H4\n"
"strexd %0, %2, %H2, [%3]\n" // *(&storage) = result, tmp = store failed
"teq %0, #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%0)
: BOOST_ATOMIC_DETAIL_ARM_ASM_TMPREG_CONSTRAINT(tmp), // %0
"=&r" (original), // %1
"=&r" (result) // %2
: "r" (&storage), // %3
"r" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
);
fence_after(order);
return original;
}
static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
storage_type original, result;
uint32_t tmp;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%0)
"1:\n"
"ldrexd %1, %H1, [%3]\n" // original = *(&storage)
"subs %2, %1, %4\n" // result = original - value
"sbc %H2, %H1, %H4\n"
"strexd %0, %2, %H2, [%3]\n" // *(&storage) = result, tmp = store failed
"teq %0, #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%0)
: BOOST_ATOMIC_DETAIL_ARM_ASM_TMPREG_CONSTRAINT(tmp), // %0
"=&r" (original), // %1
"=&r" (result) // %2
: "r" (&storage), // %3
"r" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
);
fence_after(order);
return original;
}
static BOOST_FORCEINLINE storage_type fetch_and(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
storage_type original, result;
uint32_t tmp;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%0)
"1:\n"
"ldrexd %1, %H1, [%3]\n" // original = *(&storage)
"and %2, %1, %4\n" // result = original & value
"and %H2, %H1, %H4\n"
"strexd %0, %2, %H2, [%3]\n" // *(&storage) = result, tmp = store failed
"teq %0, #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%0)
: BOOST_ATOMIC_DETAIL_ARM_ASM_TMPREG_CONSTRAINT(tmp), // %0
"=&r" (original), // %1
"=&r" (result) // %2
: "r" (&storage), // %3
"r" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
);
fence_after(order);
return original;
}
static BOOST_FORCEINLINE storage_type fetch_or(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
storage_type original, result;
uint32_t tmp;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%0)
"1:\n"
"ldrexd %1, %H1, [%3]\n" // original = *(&storage)
"orr %2, %1, %4\n" // result = original | value
"orr %H2, %H1, %H4\n"
"strexd %0, %2, %H2, [%3]\n" // *(&storage) = result, tmp = store failed
"teq %0, #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%0)
: BOOST_ATOMIC_DETAIL_ARM_ASM_TMPREG_CONSTRAINT(tmp), // %0
"=&r" (original), // %1
"=&r" (result) // %2
: "r" (&storage), // %3
"r" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
);
fence_after(order);
return original;
}
static BOOST_FORCEINLINE storage_type fetch_xor(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
fence_before(order);
storage_type original, result;
uint32_t tmp;
__asm__ __volatile__
(
BOOST_ATOMIC_DETAIL_ARM_ASM_START(%0)
"1:\n"
"ldrexd %1, %H1, [%3]\n" // original = *(&storage)
"eor %2, %1, %4\n" // result = original ^ value
"eor %H2, %H1, %H4\n"
"strexd %0, %2, %H2, [%3]\n" // *(&storage) = result, tmp = store failed
"teq %0, #0\n" // flags = tmp==0
"bne 1b\n" // if (!flags.equal) goto retry
BOOST_ATOMIC_DETAIL_ARM_ASM_END(%0)
: BOOST_ATOMIC_DETAIL_ARM_ASM_TMPREG_CONSTRAINT(tmp), // %0
"=&r" (original), // %1
"=&r" (result) // %2
: "r" (&storage), // %3
"r" (v) // %4
: BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
);
fence_after(order);
return original;
}
static BOOST_FORCEINLINE bool test_and_set(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
{
return !!exchange(storage, (storage_type)1, order);
}
static BOOST_FORCEINLINE void clear(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
{
store(storage, 0, order);
}
};
#endif // defined(BOOST_ATOMIC_DETAIL_ARM_HAS_LDREXD_STREXD)
BOOST_FORCEINLINE void thread_fence(memory_order order) BOOST_NOEXCEPT
{
if (order != memory_order_relaxed)
gcc_arm_operations_base::hardware_full_fence();
}
BOOST_FORCEINLINE void signal_fence(memory_order order) BOOST_NOEXCEPT
{
if (order != memory_order_relaxed)
__asm__ __volatile__ ("" ::: "memory");
}
} // namespace detail
} // namespace atomics
} // namespace boost
#endif // BOOST_ATOMIC_DETAIL_OPS_GCC_ARM_HPP_INCLUDED_
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