projects / apple / libc.git / blame
| Commit | Line | Data |
|---|---|---|
| 1f2f436a A |
1 | /* |
| 2 | * Copyright (c) 2003-2007 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 | #include <sys/appleapiopts.h> | |
| 30 | #include <machine/cpu_capabilities.h> | |
| 1f2f436a A |
31 | |
| 32 | #define NSEC_PER_SEC 1000*1000*1000 | |
| 33 | #define NSEC_PER_USEC 1000 | |
| 34 | ||
| 35 | .private_extern ___commpage_gettimeofday | |
| 36 | .align 4, 0x90 | |
| 37 | ___commpage_gettimeofday: | |
| 38 | // %rdi = ptr to timeval | |
| 39 | pushq %rbp // set up a frame for backtraces | |
| 40 | pushq %r12 // push callee-saved registers we want to use | |
| 41 | pushq %r13 | |
| 42 | pushq %r14 | |
| ad3c9f2a | 43 | subq $8, %rsp |
| 1f2f436a A |
44 | movq %rsp,%rbp |
| 45 | movq %rdi,%r12 // save ptr to timeval | |
| 46 | movq $(_COMM_PAGE_TIME_DATA_START),%r13 | |
| 47 | 0: | |
| 48 | movl _GTOD_GENERATION(%r13),%r14d // get generation (0 if disabled) | |
| 49 | testl %r14d,%r14d // disabled? | |
| 50 | jz 4f | |
| ad3c9f2a | 51 | |
| 1f2f436a A |
52 | call _mach_absolute_time // get %rax <- nanotime() |
| 53 | ||
| 54 | movl _GTOD_SEC_BASE(%r13),%r8d // get _COMM_PAGE_TIMESTAMP | |
| 55 | subq _GTOD_NS_BASE(%r13),%rax // generate nanoseconds since timestamp | |
| 56 | cmpl _GTOD_GENERATION(%r13),%r14d // has data changed out from under us? | |
| 57 | jne 0b | |
| 58 | ||
| 59 | movl $ NSEC_PER_SEC,%ecx | |
| 60 | movq %rax,%rdx | |
| 61 | shrq $32,%rdx // get high half of delta in %edx | |
| 62 | divl %ecx // %eax <- seconds since timestamp, %edx <- nanoseconds | |
| 63 | addl %eax,%r8d // add seconds elapsed to timestamp seconds | |
| 64 | ||
| 65 | movl $ NSEC_PER_USEC,%ecx | |
| 66 | movl %edx,%eax | |
| 67 | xorl %edx,%edx | |
| 68 | divl %ecx // divide residual ns by 1000 to get residual us in %eax | |
| 69 | ||
| 70 | movq %r8,(%r12) // store 64-bit seconds into timeval | |
| 71 | movl %eax,8(%r12) // store 32-bit useconds into timeval | |
| 72 | xorl %eax,%eax // return 0 for success | |
| 73 | 3: | |
| ad3c9f2a | 74 | addq $8, %rsp |
| 1f2f436a A |
75 | popq %r14 |
| 76 | popq %r13 | |
| 77 | popq %r12 | |
| 78 | popq %rbp | |
| 79 | ret | |
| 80 | 4: // fail | |
| 81 | movl $1,%eax | |
| 82 | jmp 3b |