arch_x86_exchange.h

// Copyright (c) Electronic Arts Inc. All rights reserved.
 
 
#ifndef EASTL_ATOMIC_INTERNAL_ARCH_X86_EXCHANGE_H
#define EASTL_ATOMIC_INTERNAL_ARCH_X86_EXCHANGE_H
 
#if defined(EA_PRAGMA_ONCE_SUPPORTED)
    #pragma once
#endif
 
 
//
// void EASTL_ARCH_ATOMIC_EXCHANGE_*_N(type, type ret, type * ptr, type val)
//
#if defined(EA_COMPILER_MSVC) && defined(EA_PROCESSOR_X86)
 
 
    #define EASTL_ARCH_ATOMIC_X86_EXCHANGE_PRE_COMPUTE_DESIRED(ret, observed, val) \
        ret = (val)
 
 
    #define EASTL_ARCH_ATOMIC_EXCHANGE_RELAXED_64(type, ret, ptr, val)      \
        EASTL_ARCH_ATOMIC_X86_OP_64_IMPL(type, ret, ptr, val, RELAXED,      \
                                         EASTL_ARCH_ATOMIC_X86_EXCHANGE_PRE_COMPUTE_DESIRED, \
                                         EASTL_ARCH_ATOMIC_X86_NOP_POST_COMPUTE_RET)
 
    #define EASTL_ARCH_ATOMIC_EXCHANGE_ACQUIRE_64(type, ret, ptr, val)      \
        EASTL_ARCH_ATOMIC_X86_OP_64_IMPL(type, ret, ptr, val, ACQUIRE,      \
                                         EASTL_ARCH_ATOMIC_X86_EXCHANGE_PRE_COMPUTE_DESIRED, \
                                         EASTL_ARCH_ATOMIC_X86_NOP_POST_COMPUTE_RET)
 
    #define EASTL_ARCH_ATOMIC_EXCHANGE_RELEASE_64(type, ret, ptr, val)      \
        EASTL_ARCH_ATOMIC_X86_OP_64_IMPL(type, ret, ptr, val, RELEASE,      \
                                         EASTL_ARCH_ATOMIC_X86_EXCHANGE_PRE_COMPUTE_DESIRED, \
                                         EASTL_ARCH_ATOMIC_X86_NOP_POST_COMPUTE_RET)
 
    #define EASTL_ARCH_ATOMIC_EXCHANGE_ACQ_REL_64(type, ret, ptr, val)      \
        EASTL_ARCH_ATOMIC_X86_OP_64_IMPL(type, ret, ptr, val, ACQ_REL,      \
                                         EASTL_ARCH_ATOMIC_X86_EXCHANGE_PRE_COMPUTE_DESIRED, \
                                         EASTL_ARCH_ATOMIC_X86_NOP_POST_COMPUTE_RET)
 
    #define EASTL_ARCH_ATOMIC_EXCHANGE_SEQ_CST_64(type, ret, ptr, val)      \
        EASTL_ARCH_ATOMIC_X86_OP_64_IMPL(type, ret, ptr, val, SEQ_CST,      \
                                         EASTL_ARCH_ATOMIC_X86_EXCHANGE_PRE_COMPUTE_DESIRED, \
                                         EASTL_ARCH_ATOMIC_X86_NOP_POST_COMPUTE_RET)
 
 
#endif
 
 
#if ((defined(__clang__) || defined(EA_COMPILER_GNUC)) && defined(EA_PROCESSOR_X86_64))
 
 
    #define EASTL_ARCH_ATOMIC_X86_EXCHANGE_128(type, ret, ptr, val, MemoryOrder) \
        {                                                                   \
            bool cmpxchgRet;                                                \
            /* This is intentionally a non-atomic 128-bit load which may observe shearing. */ \
            /* Either we do not observe *(ptr) but then the cmpxchg will fail and the observed */ \
            /* atomic load will be returned. Or the non-atomic load got lucky and the cmpxchg succeeds */ \
            /* because the observed value equals the value in *(ptr) thus we optimistically do a non-atomic load. */ \
            ret = *(ptr);                                                   \
            do                                                              \
            {                                                               \
                EA_PREPROCESSOR_JOIN(EA_PREPROCESSOR_JOIN(EASTL_ATOMIC_CMPXCHG_STRONG_, MemoryOrder), _128)(type, cmpxchgRet, ptr, &(ret), val); \
            } while (!cmpxchgRet);                                          \
        }
 
 
    #define EASTL_ARCH_ATOMIC_EXCHANGE_RELAXED_128(type, ret, ptr, val)     \
        EASTL_ARCH_ATOMIC_X86_EXCHANGE_128(type, ret, ptr, val, RELAXED)
 
    #define EASTL_ARCH_ATOMIC_EXCHANGE_ACQUIRE_128(type, ret, ptr, val)     \
        EASTL_ARCH_ATOMIC_X86_EXCHANGE_128(type, ret, ptr, val, ACQUIRE)
 
    #define EASTL_ARCH_ATOMIC_EXCHANGE_RELEASE_128(type, ret, ptr, val)     \
        EASTL_ARCH_ATOMIC_X86_EXCHANGE_128(type, ret, ptr, val, RELEASE)
 
    #define EASTL_ARCH_ATOMIC_EXCHANGE_ACQ_REL_128(type, ret, ptr, val)     \
        EASTL_ARCH_ATOMIC_X86_EXCHANGE_128(type, ret, ptr, val, ACQ_REL)
 
    #define EASTL_ARCH_ATOMIC_EXCHANGE_SEQ_CST_128(type, ret, ptr, val)     \
        EASTL_ARCH_ATOMIC_X86_EXCHANGE_128(type, ret, ptr, val, SEQ_CST)
 
 
#endif
 
 
#endif /* EASTL_ATOMIC_INTERNAL_ARCH_X86_EXCHANGE_H */