starboard/atomic.h - cobalt - Git at Google

 // Copyright 2015 The Cobalt Authors. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 // Module Overview: Starboard Atomic API
 //
 // Defines a set of atomic integer operations that can be used as lightweight
 // synchronization or as building blocks for heavier synchronization primitives.
 // Their use is very subtle and requires detailed understanding of the behavior
 // of supported architectures, so their direct use is not recommended except
 // when rigorously deemed absolutely necessary for performance reasons.

 #ifndef STARBOARD_ATOMIC_H_
 #define STARBOARD_ATOMIC_H_

 #include "starboard/configuration.h"
 #include "starboard/types.h"

 #ifdef __cplusplus
 extern "C" {
 #endif

 typedef int8_t SbAtomic8;
 typedef int32_t SbAtomic32;

 // Atomically execute:
 //      result = *ptr;
 //      if (*ptr == old_value)
 //        *ptr = new_value;
 //      return result;
 //
 // I.e., replace "*ptr" with "new_value" if "*ptr" used to be "old_value".
 // Always return the old value of "*ptr"
 //
 // This routine implies no memory barriers.
 static SbAtomic32 SbAtomicNoBarrier_CompareAndSwap(volatile SbAtomic32* ptr,
                                                    SbAtomic32 old_value,
                                                    SbAtomic32 new_value);

 // Atomically store new_value into *ptr, returning the previous value held in
 // *ptr.  This routine implies no memory barriers.
 static SbAtomic32 SbAtomicNoBarrier_Exchange(volatile SbAtomic32* ptr,
                                              SbAtomic32 new_value);

 // Atomically increment *ptr by "increment".  Returns the new value of
 // *ptr with the increment applied.  This routine implies no memory barriers.
 static SbAtomic32 SbAtomicNoBarrier_Increment(volatile SbAtomic32* ptr,
                                               SbAtomic32 increment);

 // Same as SbAtomicNoBarrier_Increment, but with a memory barrier.
 static SbAtomic32 SbAtomicBarrier_Increment(volatile SbAtomic32* ptr,
                                             SbAtomic32 increment);

 // These following lower-level operations are typically useful only to people
 // implementing higher-level synchronization operations like spinlocks, mutexes,
 // and condition-variables.  They combine CompareAndSwap(), a load, or a store
 // with appropriate memory-ordering instructions.  "Acquire" operations ensure
 // that no later memory access can be reordered ahead of the operation.
 // "Release" operations ensure that no previous memory access can be reordered
 // after the operation.  "Barrier" operations have both "Acquire" and "Release"
 // semantics.  A SbAtomicMemoryBarrier() has "Barrier" semantics, but does no
 // memory access.
 static SbAtomic32 SbAtomicAcquire_CompareAndSwap(volatile SbAtomic32* ptr,
                                                  SbAtomic32 old_value,
                                                  SbAtomic32 new_value);
 static SbAtomic32 SbAtomicRelease_CompareAndSwap(volatile SbAtomic32* ptr,
                                                  SbAtomic32 old_value,
                                                  SbAtomic32 new_value);

 static void SbAtomicMemoryBarrier();
 static void SbAtomicNoBarrier_Store(volatile SbAtomic32* ptr, SbAtomic32 value);
 static void SbAtomicAcquire_Store(volatile SbAtomic32* ptr, SbAtomic32 value);
 static void SbAtomicRelease_Store(volatile SbAtomic32* ptr, SbAtomic32 value);

 static SbAtomic32 SbAtomicNoBarrier_Load(volatile const SbAtomic32* ptr);
 static SbAtomic32 SbAtomicAcquire_Load(volatile const SbAtomic32* ptr);
 static SbAtomic32 SbAtomicRelease_Load(volatile const SbAtomic32* ptr);

 // Overloaded functions for Atomic8.
 static SbAtomic8 SbAtomicRelease_CompareAndSwap8(volatile SbAtomic8* ptr,
                                                  SbAtomic8 old_value,
                                                  SbAtomic8 new_value);
 static void SbAtomicNoBarrier_Store8(volatile SbAtomic8* ptr, SbAtomic8 value);
 static SbAtomic8 SbAtomicNoBarrier_Load8(volatile const SbAtomic8* ptr);

 // 64-bit atomic operations (only available on 64-bit processors).
 #if SB_HAS(64_BIT_ATOMICS)
 typedef int64_t SbAtomic64;

 static SbAtomic64 SbAtomicNoBarrier_CompareAndSwap64(volatile SbAtomic64* ptr,
                                                      SbAtomic64 old_value,
                                                      SbAtomic64 new_value);
 static SbAtomic64 SbAtomicNoBarrier_Exchange64(volatile SbAtomic64* ptr,
                                                SbAtomic64 new_value);
 static SbAtomic64 SbAtomicNoBarrier_Increment64(volatile SbAtomic64* ptr,
                                                 SbAtomic64 increment);
 static SbAtomic64 SbAtomicBarrier_Increment64(volatile SbAtomic64* ptr,
                                               SbAtomic64 increment);
 static SbAtomic64 SbAtomicAcquire_CompareAndSwap64(volatile SbAtomic64* ptr,
                                                    SbAtomic64 old_value,
                                                    SbAtomic64 new_value);
 static SbAtomic64 SbAtomicRelease_CompareAndSwap64(volatile SbAtomic64* ptr,
                                                    SbAtomic64 old_value,
                                                    SbAtomic64 new_value);
 static void SbAtomicNoBarrier_Store64(volatile SbAtomic64* ptr,
                                       SbAtomic64 value);
 static void SbAtomicAcquire_Store64(volatile SbAtomic64* ptr, SbAtomic64 value);
 static void SbAtomicRelease_Store64(volatile SbAtomic64* ptr, SbAtomic64 value);
 static SbAtomic64 SbAtomicNoBarrier_Load64(volatile const SbAtomic64* ptr);
 static SbAtomic64 SbAtomicAcquire_Load64(volatile const SbAtomic64* ptr);
 static SbAtomic64 SbAtomicRelease_Load64(volatile const SbAtomic64* ptr);
 #endif  // SB_HAS(64_BIT_ATOMICS)

 // Pointer-sized atomic operations. Forwards to either 32-bit or 64-bit
 // functions as appropriate.
 #if SB_SIZE_OF(POINTER) == 8
 typedef SbAtomic64 SbAtomicPtr;
 #else
 typedef SbAtomic32 SbAtomicPtr;
 #endif

 static SB_C_FORCE_INLINE SbAtomicPtr
 SbAtomicNoBarrier_CompareAndSwapPtr(volatile SbAtomicPtr* ptr,
                                     SbAtomicPtr old_value,
                                     SbAtomicPtr new_value) {
 #if SB_SIZE_OF(POINTER) == 8
   return SbAtomicNoBarrier_CompareAndSwap64(ptr, old_value, new_value);
 #else
   return SbAtomicNoBarrier_CompareAndSwap(ptr, old_value, new_value);
 #endif
 }

 static SB_C_FORCE_INLINE SbAtomicPtr
 SbAtomicNoBarrier_ExchangePtr(volatile SbAtomicPtr* ptr,
                               SbAtomicPtr new_value) {
 #if SB_SIZE_OF(POINTER) == 8
   return SbAtomicNoBarrier_Exchange64(ptr, new_value);
 #else
   return SbAtomicNoBarrier_Exchange(ptr, new_value);
 #endif
 }

 static SB_C_FORCE_INLINE SbAtomicPtr
 SbAtomicNoBarrier_IncrementPtr(volatile SbAtomicPtr* ptr,
                                SbAtomicPtr increment) {
 #if SB_SIZE_OF(POINTER) == 8
   return SbAtomicNoBarrier_Increment64(ptr, increment);
 #else
   return SbAtomicNoBarrier_Increment(ptr, increment);
 #endif
 }

 static SB_C_FORCE_INLINE SbAtomicPtr
 SbAtomicBarrier_IncrementPtr(volatile SbAtomicPtr* ptr, SbAtomicPtr increment) {
 #if SB_SIZE_OF(POINTER) == 8
   return SbAtomicBarrier_Increment64(ptr, increment);
 #else
   return SbAtomicBarrier_Increment(ptr, increment);
 #endif
 }

 static SB_C_FORCE_INLINE SbAtomicPtr
 SbAtomicAcquire_CompareAndSwapPtr(volatile SbAtomicPtr* ptr,
                                   SbAtomicPtr old_value,
                                   SbAtomicPtr new_value) {
 #if SB_SIZE_OF(POINTER) == 8
   return SbAtomicAcquire_CompareAndSwap64(ptr, old_value, new_value);
 #else
   return SbAtomicAcquire_CompareAndSwap(ptr, old_value, new_value);
 #endif
 }

 static SB_C_FORCE_INLINE SbAtomicPtr
 SbAtomicRelease_CompareAndSwapPtr(volatile SbAtomicPtr* ptr,
                                   SbAtomicPtr old_value,
                                   SbAtomicPtr new_value) {
 #if SB_SIZE_OF(POINTER) == 8
   return SbAtomicRelease_CompareAndSwap64(ptr, old_value, new_value);
 #else
   return SbAtomicRelease_CompareAndSwap(ptr, old_value, new_value);
 #endif
 }

 static SB_C_FORCE_INLINE void SbAtomicNoBarrier_StorePtr(
     volatile SbAtomicPtr* ptr,
     SbAtomicPtr value) {
 #if SB_SIZE_OF(POINTER) == 8
   SbAtomicNoBarrier_Store64(ptr, value);
 #else
   SbAtomicNoBarrier_Store(ptr, value);
 #endif
 }

 static SB_C_FORCE_INLINE void SbAtomicAcquire_StorePtr(
     volatile SbAtomicPtr* ptr,
     SbAtomicPtr value) {
 #if SB_SIZE_OF(POINTER) == 8
   SbAtomicAcquire_Store64(ptr, value);
 #else
   SbAtomicAcquire_Store(ptr, value);
 #endif
 }

 static SB_C_FORCE_INLINE void SbAtomicRelease_StorePtr(
     volatile SbAtomicPtr* ptr,
     SbAtomicPtr value) {
 #if SB_SIZE_OF(POINTER) == 8
   SbAtomicRelease_Store64(ptr, value);
 #else
   SbAtomicRelease_Store(ptr, value);
 #endif
 }

 static SB_C_FORCE_INLINE SbAtomicPtr
 SbAtomicNoBarrier_LoadPtr(volatile const SbAtomicPtr* ptr) {
 #if SB_SIZE_OF(POINTER) == 8
   return SbAtomicNoBarrier_Load64(ptr);
 #else
   return SbAtomicNoBarrier_Load(ptr);
 #endif
 }

 static SB_C_FORCE_INLINE SbAtomicPtr
 SbAtomicAcquire_LoadPtr(volatile const SbAtomicPtr* ptr) {
 #if SB_SIZE_OF(POINTER) == 8
   return SbAtomicAcquire_Load64(ptr);
 #else
   return SbAtomicAcquire_Load(ptr);
 #endif
 }

 static SB_C_FORCE_INLINE SbAtomicPtr
 SbAtomicRelease_LoadPtr(volatile const SbAtomicPtr* ptr) {
 #if SB_SIZE_OF(POINTER) == 8
   return SbAtomicRelease_Load64(ptr);
 #else
   return SbAtomicRelease_Load(ptr);
 #endif
 }

 #ifdef __cplusplus
 }  // extern "C"
 #endif

 // Include the platform definitions of these functions, which should be defined
 // as inlined. This macro is defined on the command line by GN.
 #include STARBOARD_ATOMIC_INCLUDE

 #if SB_API_VERSION < SB_ATOMIC_MOVED_API_VERSION && defined(__cplusplus)
 extern "C++" {
 #include "starboard/common/atomic.h"
 }  // extern "C++"
 #endif  // SB_API_VERSION < SB_ATOMIC_MOVED_API_VERSION  && defined(__cplusplus)

 #endif  // STARBOARD_ATOMIC_H_
	// Copyright 2015 The Cobalt Authors. All Rights Reserved.
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	// Module Overview: Starboard Atomic API
	//
	// Defines a set of atomic integer operations that can be used as lightweight
	// synchronization or as building blocks for heavier synchronization primitives.
	// Their use is very subtle and requires detailed understanding of the behavior
	// of supported architectures, so their direct use is not recommended except
	// when rigorously deemed absolutely necessary for performance reasons.

	#ifndef STARBOARD_ATOMIC_H_
	#define STARBOARD_ATOMIC_H_

	#include "starboard/configuration.h"
	#include "starboard/types.h"

	#ifdef __cplusplus
	extern "C" {
	#endif

	typedef int8_t SbAtomic8;
	typedef int32_t SbAtomic32;

	// Atomically execute:
	// result = *ptr;
	// if (*ptr == old_value)
	// *ptr = new_value;
	// return result;
	//
	// I.e., replace "ptr" with "new_value" if "ptr" used to be "old_value".
	// Always return the old value of "*ptr"
	//
	// This routine implies no memory barriers.
	static SbAtomic32 SbAtomicNoBarrier_CompareAndSwap(volatile SbAtomic32* ptr,
	SbAtomic32 old_value,
	SbAtomic32 new_value);

	// Atomically store new_value into *ptr, returning the previous value held in
	// *ptr. This routine implies no memory barriers.
	static SbAtomic32 SbAtomicNoBarrier_Exchange(volatile SbAtomic32* ptr,
	SbAtomic32 new_value);

	// Atomically increment *ptr by "increment". Returns the new value of
	// *ptr with the increment applied. This routine implies no memory barriers.
	static SbAtomic32 SbAtomicNoBarrier_Increment(volatile SbAtomic32* ptr,
	SbAtomic32 increment);

	// Same as SbAtomicNoBarrier_Increment, but with a memory barrier.
	static SbAtomic32 SbAtomicBarrier_Increment(volatile SbAtomic32* ptr,
	SbAtomic32 increment);

	// These following lower-level operations are typically useful only to people
	// implementing higher-level synchronization operations like spinlocks, mutexes,
	// and condition-variables. They combine CompareAndSwap(), a load, or a store
	// with appropriate memory-ordering instructions. "Acquire" operations ensure
	// that no later memory access can be reordered ahead of the operation.
	// "Release" operations ensure that no previous memory access can be reordered
	// after the operation. "Barrier" operations have both "Acquire" and "Release"
	// semantics. A SbAtomicMemoryBarrier() has "Barrier" semantics, but does no
	// memory access.
	static SbAtomic32 SbAtomicAcquire_CompareAndSwap(volatile SbAtomic32* ptr,
	SbAtomic32 old_value,
	SbAtomic32 new_value);
	static SbAtomic32 SbAtomicRelease_CompareAndSwap(volatile SbAtomic32* ptr,
	SbAtomic32 old_value,
	SbAtomic32 new_value);

	static void SbAtomicMemoryBarrier();
	static void SbAtomicNoBarrier_Store(volatile SbAtomic32* ptr, SbAtomic32 value);
	static void SbAtomicAcquire_Store(volatile SbAtomic32* ptr, SbAtomic32 value);
	static void SbAtomicRelease_Store(volatile SbAtomic32* ptr, SbAtomic32 value);

	static SbAtomic32 SbAtomicNoBarrier_Load(volatile const SbAtomic32* ptr);
	static SbAtomic32 SbAtomicAcquire_Load(volatile const SbAtomic32* ptr);
	static SbAtomic32 SbAtomicRelease_Load(volatile const SbAtomic32* ptr);

	// Overloaded functions for Atomic8.
	static SbAtomic8 SbAtomicRelease_CompareAndSwap8(volatile SbAtomic8* ptr,
	SbAtomic8 old_value,
	SbAtomic8 new_value);
	static void SbAtomicNoBarrier_Store8(volatile SbAtomic8* ptr, SbAtomic8 value);
	static SbAtomic8 SbAtomicNoBarrier_Load8(volatile const SbAtomic8* ptr);

	// 64-bit atomic operations (only available on 64-bit processors).
	#if SB_HAS(64_BIT_ATOMICS)
	typedef int64_t SbAtomic64;

	static SbAtomic64 SbAtomicNoBarrier_CompareAndSwap64(volatile SbAtomic64* ptr,
	SbAtomic64 old_value,
	SbAtomic64 new_value);
	static SbAtomic64 SbAtomicNoBarrier_Exchange64(volatile SbAtomic64* ptr,
	SbAtomic64 new_value);
	static SbAtomic64 SbAtomicNoBarrier_Increment64(volatile SbAtomic64* ptr,
	SbAtomic64 increment);
	static SbAtomic64 SbAtomicBarrier_Increment64(volatile SbAtomic64* ptr,
	SbAtomic64 increment);
	static SbAtomic64 SbAtomicAcquire_CompareAndSwap64(volatile SbAtomic64* ptr,
	SbAtomic64 old_value,
	SbAtomic64 new_value);
	static SbAtomic64 SbAtomicRelease_CompareAndSwap64(volatile SbAtomic64* ptr,
	SbAtomic64 old_value,
	SbAtomic64 new_value);
	static void SbAtomicNoBarrier_Store64(volatile SbAtomic64* ptr,
	SbAtomic64 value);
	static void SbAtomicAcquire_Store64(volatile SbAtomic64* ptr, SbAtomic64 value);
	static void SbAtomicRelease_Store64(volatile SbAtomic64* ptr, SbAtomic64 value);
	static SbAtomic64 SbAtomicNoBarrier_Load64(volatile const SbAtomic64* ptr);
	static SbAtomic64 SbAtomicAcquire_Load64(volatile const SbAtomic64* ptr);
	static SbAtomic64 SbAtomicRelease_Load64(volatile const SbAtomic64* ptr);
	#endif // SB_HAS(64_BIT_ATOMICS)

	// Pointer-sized atomic operations. Forwards to either 32-bit or 64-bit
	// functions as appropriate.
	#if SB_SIZE_OF(POINTER) == 8
	typedef SbAtomic64 SbAtomicPtr;
	#else
	typedef SbAtomic32 SbAtomicPtr;
	#endif

	static SB_C_FORCE_INLINE SbAtomicPtr
	SbAtomicNoBarrier_CompareAndSwapPtr(volatile SbAtomicPtr* ptr,
	SbAtomicPtr old_value,
	SbAtomicPtr new_value) {
	#if SB_SIZE_OF(POINTER) == 8
	return SbAtomicNoBarrier_CompareAndSwap64(ptr, old_value, new_value);
	#else
	return SbAtomicNoBarrier_CompareAndSwap(ptr, old_value, new_value);
	#endif
	}

	static SB_C_FORCE_INLINE SbAtomicPtr
	SbAtomicNoBarrier_ExchangePtr(volatile SbAtomicPtr* ptr,
	SbAtomicPtr new_value) {
	#if SB_SIZE_OF(POINTER) == 8
	return SbAtomicNoBarrier_Exchange64(ptr, new_value);
	#else
	return SbAtomicNoBarrier_Exchange(ptr, new_value);
	#endif
	}

	static SB_C_FORCE_INLINE SbAtomicPtr
	SbAtomicNoBarrier_IncrementPtr(volatile SbAtomicPtr* ptr,
	SbAtomicPtr increment) {
	#if SB_SIZE_OF(POINTER) == 8
	return SbAtomicNoBarrier_Increment64(ptr, increment);
	#else
	return SbAtomicNoBarrier_Increment(ptr, increment);
	#endif
	}

	static SB_C_FORCE_INLINE SbAtomicPtr
	SbAtomicBarrier_IncrementPtr(volatile SbAtomicPtr* ptr, SbAtomicPtr increment) {
	#if SB_SIZE_OF(POINTER) == 8
	return SbAtomicBarrier_Increment64(ptr, increment);
	#else
	return SbAtomicBarrier_Increment(ptr, increment);
	#endif
	}

	static SB_C_FORCE_INLINE SbAtomicPtr
	SbAtomicAcquire_CompareAndSwapPtr(volatile SbAtomicPtr* ptr,
	SbAtomicPtr old_value,
	SbAtomicPtr new_value) {
	#if SB_SIZE_OF(POINTER) == 8
	return SbAtomicAcquire_CompareAndSwap64(ptr, old_value, new_value);
	#else
	return SbAtomicAcquire_CompareAndSwap(ptr, old_value, new_value);
	#endif
	}

	static SB_C_FORCE_INLINE SbAtomicPtr
	SbAtomicRelease_CompareAndSwapPtr(volatile SbAtomicPtr* ptr,
	SbAtomicPtr old_value,
	SbAtomicPtr new_value) {
	#if SB_SIZE_OF(POINTER) == 8
	return SbAtomicRelease_CompareAndSwap64(ptr, old_value, new_value);
	#else
	return SbAtomicRelease_CompareAndSwap(ptr, old_value, new_value);
	#endif
	}

	static SB_C_FORCE_INLINE void SbAtomicNoBarrier_StorePtr(
	volatile SbAtomicPtr* ptr,
	SbAtomicPtr value) {
	#if SB_SIZE_OF(POINTER) == 8
	SbAtomicNoBarrier_Store64(ptr, value);
	#else
	SbAtomicNoBarrier_Store(ptr, value);
	#endif
	}

	static SB_C_FORCE_INLINE void SbAtomicAcquire_StorePtr(
	volatile SbAtomicPtr* ptr,
	SbAtomicPtr value) {
	#if SB_SIZE_OF(POINTER) == 8
	SbAtomicAcquire_Store64(ptr, value);
	#else
	SbAtomicAcquire_Store(ptr, value);
	#endif
	}

	static SB_C_FORCE_INLINE void SbAtomicRelease_StorePtr(
	volatile SbAtomicPtr* ptr,
	SbAtomicPtr value) {
	#if SB_SIZE_OF(POINTER) == 8
	SbAtomicRelease_Store64(ptr, value);
	#else
	SbAtomicRelease_Store(ptr, value);
	#endif
	}

	static SB_C_FORCE_INLINE SbAtomicPtr
	SbAtomicNoBarrier_LoadPtr(volatile const SbAtomicPtr* ptr) {
	#if SB_SIZE_OF(POINTER) == 8
	return SbAtomicNoBarrier_Load64(ptr);
	#else
	return SbAtomicNoBarrier_Load(ptr);
	#endif
	}

	static SB_C_FORCE_INLINE SbAtomicPtr
	SbAtomicAcquire_LoadPtr(volatile const SbAtomicPtr* ptr) {
	#if SB_SIZE_OF(POINTER) == 8
	return SbAtomicAcquire_Load64(ptr);
	#else
	return SbAtomicAcquire_Load(ptr);
	#endif
	}

	static SB_C_FORCE_INLINE SbAtomicPtr
	SbAtomicRelease_LoadPtr(volatile const SbAtomicPtr* ptr) {
	#if SB_SIZE_OF(POINTER) == 8
	return SbAtomicRelease_Load64(ptr);
	#else
	return SbAtomicRelease_Load(ptr);
	#endif
	}

	#ifdef __cplusplus
	} // extern "C"
	#endif

	// Include the platform definitions of these functions, which should be defined
	// as inlined. This macro is defined on the command line by GN.
	#include STARBOARD_ATOMIC_INCLUDE

	#if SB_API_VERSION < SB_ATOMIC_MOVED_API_VERSION && defined(__cplusplus)
	extern "C++" {
	#include "starboard/common/atomic.h"
	} // extern "C++"
	#endif // SB_API_VERSION < SB_ATOMIC_MOVED_API_VERSION && defined(__cplusplus)

	#endif // STARBOARD_ATOMIC_H_