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Commit	Line	Data
	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 100010001000
	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
	44	0:
	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
	71	3:
	72	pop %ebx
	73	pop %esi
	74	pop %ebp
	75	ret
	76	4: /* 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
	94	0:
	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
	120	3:
	121	addq $8, %rsp
	122	popq %r14
	123	popq %r13
	124	popq %r12
	125	popq %rbp
	126	ret
	127	4: // fail
	128	movl $1,%eax
	129	jmp 3b
	130
	131	#endif