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      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. */
     57 1:
     58 	RETC			/* return 0 */
     59 	SET_SIZE(gettimeofday)
     60 
     61