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// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*-
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// Implementation of atomic operations for ppc-linux. This file should not
// be included directly. Clients should instead include
// "base/atomicops.h".
#ifndef BASE_ATOMICOPS_INTERNALS_LINUXPPC_H_
#define BASE_ATOMICOPS_INTERNALS_LINUXPPC_H_
typedef int32_t Atomic32;
#ifdef __PPC64__
#define BASE_HAS_ATOMIC64 1
#endif
namespace base {
namespace subtle {
static inline void _sync(void) {
__asm__ __volatile__("sync": : : "memory");
}
static inline void _lwsync(void) {
// gcc defines __NO_LWSYNC__ when appropriate; see
// http://gcc.gnu.org/ml/gcc-patches/2006-11/msg01238.html
#ifdef __NO_LWSYNC__
__asm__ __volatile__("msync": : : "memory");
#else
__asm__ __volatile__("lwsync": : : "memory");
#endif
}
static inline void _isync(void) {
__asm__ __volatile__("isync": : : "memory");
}
static inline Atomic32 OSAtomicAdd32(Atomic32 amount, Atomic32 *value) {
Atomic32 t;
__asm__ __volatile__(
"1: lwarx %0,0,%3\n\
add %0,%2,%0\n\
stwcx. %0,0,%3 \n\
bne- 1b"
: "=&r" (t), "+m" (*value)
: "r" (amount), "r" (value)
: "cc");
return t;
}
static inline Atomic32 OSAtomicAdd32Barrier(Atomic32 amount, Atomic32 *value) {
Atomic32 t;
_lwsync();
t = OSAtomicAdd32(amount, value);
// This is based on the code snippet in the architecture manual (Vol
// 2, Appendix B). It's a little tricky: correctness depends on the
// fact that the code right before this (in OSAtomicAdd32) has a
// conditional branch with a data dependency on the update.
// Otherwise, we'd have to use sync.
_isync();
return t;
}
static inline bool OSAtomicCompareAndSwap32(Atomic32 old_value,
Atomic32 new_value,
Atomic32 *value) {
Atomic32 prev;
__asm__ __volatile__(
"1: lwarx %0,0,%2\n\
cmpw 0,%0,%3\n\
bne- 2f\n\
stwcx. %4,0,%2\n\
bne- 1b\n\
2:"
: "=&r" (prev), "+m" (*value)
: "r" (value), "r" (old_value), "r" (new_value)
: "cc");
return prev == old_value;
}
static inline Atomic32 OSAtomicCompareAndSwap32Acquire(Atomic32 old_value,
Atomic32 new_value,
Atomic32 *value) {
Atomic32 t;
t = OSAtomicCompareAndSwap32(old_value, new_value, value);
// This is based on the code snippet in the architecture manual (Vol
// 2, Appendix B). It's a little tricky: correctness depends on the
// fact that the code right before this (in
// OSAtomicCompareAndSwap32) has a conditional branch with a data
// dependency on the update. Otherwise, we'd have to use sync.
_isync();
return t;
}
static inline Atomic32 OSAtomicCompareAndSwap32Release(Atomic32 old_value,
Atomic32 new_value,
Atomic32 *value) {
_lwsync();
return OSAtomicCompareAndSwap32(old_value, new_value, value);
}
typedef int64_t Atomic64;
inline void MemoryBarrier() {
// This can't be _lwsync(); we need to order the immediately
// preceding stores against any load that may follow, but lwsync
// doesn't guarantee that.
_sync();
}
// 32-bit Versions.
inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32 *ptr,
Atomic32 old_value,
Atomic32 new_value) {
Atomic32 prev_value;
do {
if (OSAtomicCompareAndSwap32(old_value, new_value,
const_cast<Atomic32*>(ptr))) {
return old_value;
}
prev_value = *ptr;
} while (prev_value == old_value);
return prev_value;
}
inline Atomic32 NoBarrier_AtomicExchange(volatile Atomic32 *ptr,
Atomic32 new_value) {
Atomic32 old_value;
do {
old_value = *ptr;
} while (!OSAtomicCompareAndSwap32(old_value, new_value,
const_cast<Atomic32*>(ptr)));
return old_value;
}
inline Atomic32 Acquire_AtomicExchange(volatile Atomic32 *ptr,
Atomic32 new_value) {
Atomic32 old_value;
do {
old_value = *ptr;
} while (!OSAtomicCompareAndSwap32Acquire(old_value, new_value,
const_cast<Atomic32*>(ptr)));
return old_value;
}
inline Atomic32 Release_AtomicExchange(volatile Atomic32 *ptr,
Atomic32 new_value) {
Atomic32 old_value;
do {
old_value = *ptr;
} while (!OSAtomicCompareAndSwap32Release(old_value, new_value,
const_cast<Atomic32*>(ptr)));
return old_value;
}
inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32 *ptr,
Atomic32 old_value,
Atomic32 new_value) {
Atomic32 prev_value;
do {
if (OSAtomicCompareAndSwap32Acquire(old_value, new_value,
const_cast<Atomic32*>(ptr))) {
return old_value;
}
prev_value = *ptr;
} while (prev_value == old_value);
return prev_value;
}
inline Atomic32 Release_CompareAndSwap(volatile Atomic32 *ptr,
Atomic32 old_value,
Atomic32 new_value) {
Atomic32 prev_value;
do {
if (OSAtomicCompareAndSwap32Release(old_value, new_value,
const_cast<Atomic32*>(ptr))) {
return old_value;
}
prev_value = *ptr;
} while (prev_value == old_value);
return prev_value;
}
#ifdef __PPC64__
// 64-bit Versions.
static inline Atomic64 OSAtomicAdd64(Atomic64 amount, Atomic64 *value) {
Atomic64 t;
__asm__ __volatile__(
"1: ldarx %0,0,%3\n\
add %0,%2,%0\n\
stdcx. %0,0,%3 \n\
bne- 1b"
: "=&r" (t), "+m" (*value)
: "r" (amount), "r" (value)
: "cc");
return t;
}
static inline Atomic64 OSAtomicAdd64Barrier(Atomic64 amount, Atomic64 *value) {
Atomic64 t;
_lwsync();
t = OSAtomicAdd64(amount, value);
// This is based on the code snippet in the architecture manual (Vol
// 2, Appendix B). It's a little tricky: correctness depends on the
// fact that the code right before this (in OSAtomicAdd64) has a
// conditional branch with a data dependency on the update.
// Otherwise, we'd have to use sync.
_isync();
return t;
}
static inline bool OSAtomicCompareAndSwap64(Atomic64 old_value,
Atomic64 new_value,
Atomic64 *value) {
Atomic64 prev;
__asm__ __volatile__(
"1: ldarx %0,0,%2\n\
cmpd 0,%0,%3\n\
bne- 2f\n\
stdcx. %4,0,%2\n\
bne- 1b\n\
2:"
: "=&r" (prev), "+m" (*value)
: "r" (value), "r" (old_value), "r" (new_value)
: "cc");
return prev == old_value;
}
static inline Atomic64 OSAtomicCompareAndSwap64Acquire(Atomic64 old_value,
Atomic64 new_value,
Atomic64 *value) {
Atomic64 t;
t = OSAtomicCompareAndSwap64(old_value, new_value, value);
// This is based on the code snippet in the architecture manual (Vol
// 2, Appendix B). It's a little tricky: correctness depends on the
// fact that the code right before this (in
// OSAtomicCompareAndSwap64) has a conditional branch with a data
// dependency on the update. Otherwise, we'd have to use sync.
_isync();
return t;
}
static inline Atomic64 OSAtomicCompareAndSwap64Release(Atomic64 old_value,
Atomic64 new_value,
Atomic64 *value) {
_lwsync();
return OSAtomicCompareAndSwap64(old_value, new_value, value);
}
inline Atomic64 NoBarrier_CompareAndSwap(volatile Atomic64 *ptr,
Atomic64 old_value,
Atomic64 new_value) {
Atomic64 prev_value;
do {
if (OSAtomicCompareAndSwap64(old_value, new_value,
const_cast<Atomic64*>(ptr))) {
return old_value;
}
prev_value = *ptr;
} while (prev_value == old_value);
return prev_value;
}
inline Atomic64 NoBarrier_AtomicExchange(volatile Atomic64 *ptr,
Atomic64 new_value) {
Atomic64 old_value;
do {
old_value = *ptr;
} while (!OSAtomicCompareAndSwap64(old_value, new_value,
const_cast<Atomic64*>(ptr)));
return old_value;
}
inline Atomic64 Acquire_AtomicExchange(volatile Atomic64 *ptr,
Atomic64 new_value) {
Atomic64 old_value;
do {
old_value = *ptr;
} while (!OSAtomicCompareAndSwap64Acquire(old_value, new_value,
const_cast<Atomic64*>(ptr)));
return old_value;
}
inline Atomic64 Release_AtomicExchange(volatile Atomic64 *ptr,
Atomic64 new_value) {
Atomic64 old_value;
do {
old_value = *ptr;
} while (!OSAtomicCompareAndSwap64Release(old_value, new_value,
const_cast<Atomic64*>(ptr)));
return old_value;
}
inline Atomic64 Acquire_CompareAndSwap(volatile Atomic64 *ptr,
Atomic64 old_value,
Atomic64 new_value) {
Atomic64 prev_value;
do {
if (OSAtomicCompareAndSwap64Acquire(old_value, new_value,
const_cast<Atomic64*>(ptr))) {
return old_value;
}
prev_value = *ptr;
} while (prev_value == old_value);
return prev_value;
}
inline Atomic64 Release_CompareAndSwap(volatile Atomic64 *ptr,
Atomic64 old_value,
Atomic64 new_value) {
Atomic64 prev_value;
do {
if (OSAtomicCompareAndSwap64Release(old_value, new_value,
const_cast<Atomic64*>(ptr))) {
return old_value;
}
prev_value = *ptr;
} while (prev_value == old_value);
return prev_value;
}
#endif
inline void NoBarrier_Store(volatile Atomic32 *ptr, Atomic32 value) {
*ptr = value;
}
inline void Release_Store(volatile Atomic32 *ptr, Atomic32 value) {
_lwsync();
*ptr = value;
}
inline Atomic32 NoBarrier_Load(volatile const Atomic32 *ptr) {
return *ptr;
}
inline Atomic32 Acquire_Load(volatile const Atomic32 *ptr) {
Atomic32 value = *ptr;
_lwsync();
return value;
}
#ifdef __PPC64__
// 64-bit Versions.
inline void NoBarrier_Store(volatile Atomic64 *ptr, Atomic64 value) {
*ptr = value;
}
inline void Release_Store(volatile Atomic64 *ptr, Atomic64 value) {
_lwsync();
*ptr = value;
}
inline Atomic64 NoBarrier_Load(volatile const Atomic64 *ptr) {
return *ptr;
}
inline Atomic64 Acquire_Load(volatile const Atomic64 *ptr) {
Atomic64 value = *ptr;
_lwsync();
return value;
}
#endif
} // namespace base::subtle
} // namespace base
#endif // BASE_ATOMICOPS_INTERNALS_LINUXPPC_H_