projects / apple / libplatform.git / blame
| Commit | Line | Data |
|---|---|---|
| ada7c492 A |
1 | /* |
| 2 | * Copyright (c) 2013 Apple Inc. All rights reserved. | |
| 3 | * | |
| 4 | * @APPLE_APACHE_LICENSE_HEADER_START@ | |
| 5 | * | |
| 6 | * Licensed under the Apache License, Version 2.0 (the "License"); | |
| 7 | * you may not use this file except in compliance with the License. | |
| 8 | * You may obtain a copy of the License at | |
| 9 | * | |
| 10 | * http://www.apache.org/licenses/LICENSE-2.0 | |
| 11 | * | |
| 12 | * Unless required by applicable law or agreed to in writing, software | |
| 13 | * distributed under the License is distributed on an "AS IS" BASIS, | |
| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
| 15 | * See the License for the specific language governing permissions and | |
| 16 | * limitations under the License. | |
| 17 | * | |
| 18 | * @APPLE_APACHE_LICENSE_HEADER_END@ | |
| 19 | */ | |
| 20 | ||
| 21 | /* | |
| 22 | * IMPORTANT: This header file describes INTERNAL interfaces to libplatform | |
| 23 | * which are subject to change in future releases of Mac OS X. Any applications | |
| 24 | * relying on these interfaces WILL break. | |
| 25 | */ | |
| 26 | ||
| 27 | #ifndef __OS_YIELD__ | |
| 28 | #define __OS_YIELD__ | |
| 29 | ||
| 30 | #include <TargetConditionals.h> | |
| 31 | ||
| 32 | #pragma mark - | |
| 33 | #pragma mark _os_wait_until | |
| 34 | ||
| 35 | #if OS_ATOMIC_UP | |
| 36 | #define _os_wait_until(c) do { \ | |
| 37 | int _spins = 0; \ | |
| 38 | while (unlikely(!(c))) { \ | |
| 39 | _spins++; \ | |
| 40 | _os_preemption_yield(_spins); \ | |
| 41 | } } while (0) | |
| 438624e0 | 42 | #else |
| ada7c492 A |
43 | // <rdar://problem/15508918> |
| 44 | #ifndef OS_WAIT_SPINS | |
| 45 | #define OS_WAIT_SPINS 1024 | |
| 46 | #endif | |
| 47 | #define _os_wait_until(c) do { \ | |
| 48 | int _spins = -(OS_WAIT_SPINS); \ | |
| 49 | while (unlikely(!(c))) { \ | |
| 50 | if (unlikely(_spins++ >= 0)) { \ | |
| 51 | _os_preemption_yield(_spins); \ | |
| 52 | } else { \ | |
| 53 | os_hardware_pause(); \ | |
| 54 | } \ | |
| 55 | } } while (0) | |
| ada7c492 A |
56 | #endif |
| 57 | ||
| 58 | #pragma mark - | |
| 59 | #pragma mark os_hardware_pause | |
| 60 | ||
| 61 | #if defined(__x86_64__) || defined(__i386__) | |
| 62 | #define os_hardware_pause() __asm__("pause") | |
| 63 | #elif (defined(__arm__) && defined(_ARM_ARCH_7) && defined(__thumb__)) || \ | |
| 64 | defined(__arm64__) | |
| 65 | #define os_hardware_pause() __asm__("yield") | |
| 66 | #define os_hardware_wfe() __asm__("wfe") | |
| 67 | #else | |
| 68 | #define os_hardware_pause() __asm__("") | |
| 69 | #endif | |
| 70 | ||
| 71 | #pragma mark - | |
| 72 | #pragma mark _os_preemption_yield | |
| 73 | ||
| ada7c492 | 74 | #define _os_preemption_yield(n) thread_switch(MACH_PORT_NULL, \ |
| 438624e0 | 75 | SWITCH_OPTION_OSLOCK_DEPRESS, (mach_msg_timeout_t)(n)) |
| ada7c492 A |
76 | |
| 77 | #endif // __OS_YIELD__ |