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> 31 32#define NSEC_PER_SEC 1000*1000*1000 33#define NSEC_PER_USEC 1000 34 35#if defined(__i386__) 36 37 .align 4 38 .globl ___commpage_gettimeofday 39___commpage_gettimeofday: 40 push %ebp 41 mov %esp,%ebp 42 push %esi 43 push %ebx 440: 45 movl _COMM_PAGE_GTOD_GENERATION,%esi /* get generation (0 if disabled) */ 46 testl %esi,%esi /* disabled? */ 47 jz 4f 48 49 call _mach_absolute_time /* get nanotime in %edx:%eax */ 50 51 sub _COMM_PAGE_GTOD_NS_BASE,%eax 52 sbb _COMM_PAGE_GTOD_NS_BASE+4,%edx 53 mov _COMM_PAGE_GTOD_SEC_BASE,%ebx /* load all the data before checking generation */ 54 mov $ NSEC_PER_SEC,%ecx 55 56 cmpl _COMM_PAGE_GTOD_GENERATION,%esi /* has time data changed out from under us? */ 57 jne 0b 58 59 div %ecx 60 add %eax,%ebx 61 62 mov $ NSEC_PER_USEC,%ecx 63 mov %edx,%eax 64 xor %edx,%edx 65 div %ecx 66 67 mov 8(%ebp),%ecx 68 mov %ebx,(%ecx) 69 mov %eax,4(%ecx) 70 xor %eax,%eax 713: 72 pop %ebx 73 pop %esi 74 pop %ebp 75 ret 764: /* fail */ 77 movl $1,%eax 78 jmp 3b 79 80#elif defined(__x86_64__) 81 82 .align 4, 0x90 83 .globl ___commpage_gettimeofday 84___commpage_gettimeofday: 85// %rdi = ptr to timeval 86 pushq %rbp // set up a frame for backtraces 87 pushq %r12 // push callee-saved registers we want to use 88 pushq %r13 89 pushq %r14 90 subq $8, %rsp 91 movq %rsp,%rbp 92 movq %rdi,%r12 // save ptr to timeval 93 movq $(_COMM_PAGE_TIME_DATA_START),%r13 940: 95 movl _GTOD_GENERATION(%r13),%r14d // get generation (0 if disabled) 96 testl %r14d,%r14d // disabled? 97 jz 4f 98 99 call _mach_absolute_time // get %rax <- nanotime() 100 101 movl _GTOD_SEC_BASE(%r13),%r8d // get _COMM_PAGE_TIMESTAMP 102 subq _GTOD_NS_BASE(%r13),%rax // generate nanoseconds since timestamp 103 cmpl _GTOD_GENERATION(%r13),%r14d // has data changed out from under us? 104 jne 0b 105 106 movl $ NSEC_PER_SEC,%ecx 107 movq %rax,%rdx 108 shrq $32,%rdx // get high half of delta in %edx 109 divl %ecx // %eax <- seconds since timestamp, %edx <- nanoseconds 110 addl %eax,%r8d // add seconds elapsed to timestamp seconds 111 112 movl $ NSEC_PER_USEC,%ecx 113 movl %edx,%eax 114 xorl %edx,%edx 115 divl %ecx // divide residual ns by 1000 to get residual us in %eax 116 117 movq %r8,(%r12) // store 64-bit seconds into timeval 118 movl %eax,8(%r12) // store 32-bit useconds into timeval 119 xorl %eax,%eax // return 0 for success 1203: 121 addq $8, %rsp 122 popq %r14 123 popq %r13 124 popq %r12 125 popq %rbp 126 ret 1274: // fail 128 movl $1,%eax 129 jmp 3b 130 131#endif 132