projects / apple / xnu.git / blame
| Commit | Line | Data |
|---|---|---|
| 0a7de745 A |
1 | /* |
| 2 | * Copyright (c) 2016 Apple Inc. All rights reserved. | |
| 3 | * | |
| 4 | * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ | |
| 5 | * | |
| 6 | * This file contains Original Code and/or Modifications of Original Code | |
| 7 | * as defined in and that are subject to the Apple Public Source License | |
| 8 | * Version 2.0 (the 'License'). You may not use this file except in | |
| 9 | * compliance with the License. The rights granted to you under the License | |
| 10 | * may not be used to create, or enable the creation or redistribution of, | |
| 11 | * unlawful or unlicensed copies of an Apple operating system, or to | |
| 12 | * circumvent, violate, or enable the circumvention or violation of, any | |
| 13 | * terms of an Apple operating system software license agreement. | |
| 14 | * | |
| 15 | * Please obtain a copy of the License at | |
| 16 | * http://www.opensource.apple.com/apsl/ and read it before using this file. | |
| 17 | * | |
| 18 | * The Original Code and all software distributed under the License are | |
| 19 | * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER | |
| 20 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, | |
| 21 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, | |
| 22 | * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. | |
| 23 | * Please see the License for the specific language governing rights and | |
| 24 | * limitations under the License. | |
| 25 | * | |
| 26 | * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ | |
| 27 | */ | |
| 28 | ||
| 29 | #ifndef REMOTE_TIME_H | |
| 30 | #define REMOTE_TIME_H | |
| 31 | ||
| 32 | #include <sys/cdefs.h> | |
| 33 | #include <stdint.h> | |
| 34 | #include <os/overflow.h> | |
| 35 | ||
| 36 | __BEGIN_DECLS | |
| 37 | /* bt_params is an ABI for tracing tools */ | |
| 38 | struct bt_params { | |
| 39 | double rate; | |
| 40 | uint64_t base_local_ts; | |
| 41 | uint64_t base_remote_ts; | |
| 42 | }; | |
| 43 | ||
| 44 | /* local_ts_ns should be in nanoseconds */ | |
| 45 | static inline uint64_t | |
| 46 | mach_bridge_compute_timestamp(uint64_t local_ts_ns, struct bt_params *params) | |
| 47 | { | |
| 48 | if (!params || params->rate == 0.0) { | |
| 49 | return 0; | |
| 50 | } | |
| 51 | /* | |
| 52 | * Formula to compute remote_timestamp | |
| 53 | * remote_timestamp = (bt_params.rate * (local_ts_ns - bt_params.base_local_ts)) | |
| 54 | * + bt_params.base_remote_ts | |
| 55 | */ | |
| 56 | int64_t remote_ts = 0; | |
| 57 | int64_t rate_prod = 0; | |
| cb323159 A |
58 | /* To avoid precision loss due to typecasting from int64_t to double */ |
| 59 | if (params->rate != 1.0) { | |
| 60 | rate_prod = (int64_t)(params->rate * (double)((int64_t)local_ts_ns - (int64_t)params->base_local_ts)); | |
| 61 | } else { | |
| 62 | rate_prod = (int64_t)local_ts_ns - (int64_t)params->base_local_ts; | |
| 63 | } | |
| 0a7de745 A |
64 | if (os_add_overflow((int64_t)params->base_remote_ts, rate_prod, &remote_ts)) { |
| 65 | return 0; | |
| 66 | } | |
| 67 | ||
| 68 | return (uint64_t)remote_ts; | |
| 69 | } | |
| 70 | ||
| 71 | uint64_t mach_bridge_remote_time(uint64_t); | |
| 72 | __END_DECLS | |
| 73 | ||
| 74 | #endif /* REMOTE_TIME_H */ |