xref: /titanic_41/usr/src/lib/libc/amd64/sys/gettimeofday.s (revision 9c9af2590af49bb395bc8d2eace0f2d4ea16d165)
1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27	.file	"gettimeofday.s"
28
29#include "SYS.h"
30
31	ANSI_PRAGMA_WEAK(gettimeofday,function)
32
33/*
34 *  implements int gettimeofday(struct timeval *tp, void *tzp)
35 *
36 *	note that tzp is always ignored
37 */
38
39	ENTRY(gettimeofday)
40/*
41 *	use long long gethrestime()
42 */
43	pushq	%rdi		/* pointer to timeval */
44	SYSFASTTRAP(GETHRESTIME)
45/*
46 *	gethrestime trap returns seconds in %eax, nsecs in %edx
47 *	need to convert nsecs to usecs & store into area pointed
48 *	to by struct timeval * argument.
49 */
50	popq	%rcx		/* pointer to timeval */
51	jrcxz	1f		/* bail if we get a null pointer */
52	movq	%rax, (%rcx)	/* store seconds into timeval ptr	 */
53	movl	$274877907, %eax	/* divide by 1000 as impl. by gcc */
54	imull	%edx		/* See Hacker's Delight pg 162 */
55	sarl	$6, %edx	/* simplified by 0 <= nsec <= 1e9 */
56	movq	%rdx, 8(%rcx)	/* store usecs into timeval ptr + 8. */
571:
58	RETC			/* return 0 */
59	SET_SIZE(gettimeofday)
60
61