xref: /titanic_41/usr/src/lib/libc/amd64/sys/gettimeofday.s (revision 505d05c73a6e56769f263d4803b22eddd168ee24)
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, Version 1.0 only
6 * (the "License").  You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22/*
23 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27#pragma ident	"%Z%%M%	%I%	%E% SMI"
28
29	.file	"%M%"
30
31#include <sys/asm_linkage.h>
32
33	ANSI_PRAGMA_WEAK(gettimeofday,function)
34
35#include "SYS.h"
36
37/*
38 *  implements int gettimeofday(struct timeval *tp, void *tzp)
39 *
40 *	note that tzp is always ignored
41 */
42
43	ENTRY(_gettimeofday)
44/*
45 *	use long long gethrestime()
46 */
47	pushq	%rdi		/* pointer to timeval */
48	SYSFASTTRAP(GETHRESTIME)
49/*
50 *	gethrestime trap returns seconds in %eax, nsecs in %edx
51 *	need to convert nsecs to usecs & store into area pointed
52 *	to by struct timeval * argument.
53 */
54	popq	%rcx		/* pointer to timeval */
55	jrcxz	1f		/* bail if we get a null pointer */
56	movq	%rax, (%rcx)	/* store seconds into timeval ptr	 */
57	movl	$274877907, %eax	/* divide by 1000 as impl. by gcc */
58	imull	%edx		/* See Hacker's Delight pg 162 */
59	sarl	$6, %edx	/* simplified by 0 <= nsec <= 1e9 */
60	movq	%rdx, 8(%rcx)	/* store usecs into timeval ptr + 8. */
611:
62	RETC			/* return 0 */
63	SET_SIZE(_gettimeofday)
64
65