David Garcia Quintas | 2425bbb | 2016-01-25 17:32:48 -0800 | [diff] [blame] | 1 | /* |
| 2 | * |
Craig Tiller | 6169d5f | 2016-03-31 07:46:18 -0700 | [diff] [blame^] | 3 | * Copyright 2015, Google Inc. |
David Garcia Quintas | 2425bbb | 2016-01-25 17:32:48 -0800 | [diff] [blame] | 4 | * All rights reserved. |
| 5 | * |
| 6 | * Redistribution and use in source and binary forms, with or without |
| 7 | * modification, are permitted provided that the following conditions are |
| 8 | * met: |
| 9 | * |
| 10 | * * Redistributions of source code must retain the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer. |
| 12 | * * Redistributions in binary form must reproduce the above |
| 13 | * copyright notice, this list of conditions and the following disclaimer |
| 14 | * in the documentation and/or other materials provided with the |
| 15 | * distribution. |
| 16 | * * Neither the name of Google Inc. nor the names of its |
| 17 | * contributors may be used to endorse or promote products derived from |
| 18 | * this software without specific prior written permission. |
| 19 | * |
| 20 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 21 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 22 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 23 | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 24 | * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 25 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 26 | * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 27 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 28 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 29 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 30 | * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 31 | * |
| 32 | */ |
| 33 | |
| 34 | #ifndef GRPC_IMPL_CODEGEN_ATM_H |
| 35 | #define GRPC_IMPL_CODEGEN_ATM_H |
| 36 | |
| 37 | /* This interface provides atomic operations and barriers. |
| 38 | It is internal to gpr support code and should not be used outside it. |
| 39 | |
| 40 | If an operation with acquire semantics precedes another memory access by the |
| 41 | same thread, the operation will precede that other access as seen by other |
| 42 | threads. |
| 43 | |
| 44 | If an operation with release semantics follows another memory access by the |
| 45 | same thread, the operation will follow that other access as seen by other |
| 46 | threads. |
| 47 | |
| 48 | Routines with "acq" or "full" in the name have acquire semantics. Routines |
| 49 | with "rel" or "full" in the name have release semantics. Routines with |
| 50 | "no_barrier" in the name have neither acquire not release semantics. |
| 51 | |
| 52 | The routines may be implemented as macros. |
| 53 | |
| 54 | // Atomic operations act on an intergral_type gpr_atm that is guaranteed to |
| 55 | // be the same size as a pointer. |
| 56 | typedef intptr_t gpr_atm; |
| 57 | |
| 58 | // A memory barrier, providing both acquire and release semantics, but not |
| 59 | // otherwise acting on memory. |
| 60 | void gpr_atm_full_barrier(void); |
| 61 | |
| 62 | // Atomically return *p, with acquire semantics. |
| 63 | gpr_atm gpr_atm_acq_load(gpr_atm *p); |
| 64 | |
| 65 | // Atomically set *p = value, with release semantics. |
| 66 | void gpr_atm_rel_store(gpr_atm *p, gpr_atm value); |
| 67 | |
| 68 | // Atomically add delta to *p, and return the old value of *p, with |
| 69 | // the barriers specified. |
| 70 | gpr_atm gpr_atm_no_barrier_fetch_add(gpr_atm *p, gpr_atm delta); |
| 71 | gpr_atm gpr_atm_full_fetch_add(gpr_atm *p, gpr_atm delta); |
| 72 | |
| 73 | // Atomically, if *p==o, set *p=n and return non-zero otherwise return 0, |
| 74 | // with the barriers specified if the operation succeeds. |
| 75 | int gpr_atm_no_barrier_cas(gpr_atm *p, gpr_atm o, gpr_atm n); |
| 76 | int gpr_atm_acq_cas(gpr_atm *p, gpr_atm o, gpr_atm n); |
| 77 | int gpr_atm_rel_cas(gpr_atm *p, gpr_atm o, gpr_atm n); |
| 78 | */ |
| 79 | |
| 80 | #include <grpc/impl/codegen/port_platform.h> |
| 81 | |
| 82 | #if defined(GPR_GCC_ATOMIC) |
| 83 | #include <grpc/impl/codegen/atm_gcc_atomic.h> |
| 84 | #elif defined(GPR_GCC_SYNC) |
| 85 | #include <grpc/impl/codegen/atm_gcc_sync.h> |
| 86 | #elif defined(GPR_WIN32_ATOMIC) |
| 87 | #include <grpc/impl/codegen/atm_win32.h> |
| 88 | #else |
| 89 | #error could not determine platform for atm |
| 90 | #endif |
| 91 | |
| 92 | #endif /* GRPC_IMPL_CODEGEN_ATM_H */ |