xref: /titanic_44/usr/src/lib/libc/sparc/sys/gettimeofday.s (revision 9a70fc3be3b1e966bf78825cdb8d509963a6f0a1)
17c478bd9Sstevel@tonic-gate/*
27c478bd9Sstevel@tonic-gate * CDDL HEADER START
37c478bd9Sstevel@tonic-gate *
47c478bd9Sstevel@tonic-gate * The contents of this file are subject to the terms of the
57257d1b4Sraf * Common Development and Distribution License (the "License").
67257d1b4Sraf * You may not use this file except in compliance with the License.
77c478bd9Sstevel@tonic-gate *
87c478bd9Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
97c478bd9Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing.
107c478bd9Sstevel@tonic-gate * See the License for the specific language governing permissions
117c478bd9Sstevel@tonic-gate * and limitations under the License.
127c478bd9Sstevel@tonic-gate *
137c478bd9Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each
147c478bd9Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
157c478bd9Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the
167c478bd9Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying
177c478bd9Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner]
187c478bd9Sstevel@tonic-gate *
197c478bd9Sstevel@tonic-gate * CDDL HEADER END
207c478bd9Sstevel@tonic-gate */
217c478bd9Sstevel@tonic-gate
227c478bd9Sstevel@tonic-gate/*
237257d1b4Sraf * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
247c478bd9Sstevel@tonic-gate * Use is subject to license terms.
257c478bd9Sstevel@tonic-gate */
267c478bd9Sstevel@tonic-gate
277257d1b4Sraf/*	Copyright (c) 1988 AT&T	*/
287257d1b4Sraf/*	  All Rights Reserved	*/
297257d1b4Sraf
30*9a70fc3bSMark J. Nelson	.file	"gettimeofday.s"
317c478bd9Sstevel@tonic-gate
327c478bd9Sstevel@tonic-gate/*
337c478bd9Sstevel@tonic-gate * C library -- gettimeofday
347c478bd9Sstevel@tonic-gate * int gettimeofday (struct timeval *tp);
357c478bd9Sstevel@tonic-gate */
367c478bd9Sstevel@tonic-gate
377257d1b4Sraf#include "SYS.h"
387c478bd9Sstevel@tonic-gate
397c478bd9Sstevel@tonic-gate	ANSI_PRAGMA_WEAK(gettimeofday,function)
407c478bd9Sstevel@tonic-gate
417c478bd9Sstevel@tonic-gate/*
427c478bd9Sstevel@tonic-gate * The interface below calls the trap (0x27) to get the timestamp in
437c478bd9Sstevel@tonic-gate * secs and nsecs. It than converts the nsecs value into usecs before
447c478bd9Sstevel@tonic-gate * it returns.
457c478bd9Sstevel@tonic-gate *
467c478bd9Sstevel@tonic-gate * The algorithm used to perform the division by 1000 is based upon
477c478bd9Sstevel@tonic-gate * algorithms for division based upon multiplication by invariant
487c478bd9Sstevel@tonic-gate * integers.  Relevant sources for these algorithms are:
497c478bd9Sstevel@tonic-gate *
507c478bd9Sstevel@tonic-gate * Granlund, T.; Montgomery, P.L.: "Division by Invariant Integers using
517c478bd9Sstevel@tonic-gate * Multiplication". SIGPLAN Notices, Vol. 29, June 1994, page 61.
527c478bd9Sstevel@tonic-gate *
537c478bd9Sstevel@tonic-gate * Magenheimer, D.J.; et al: "Integer Multiplication and Division on the HP
547c478bd9Sstevel@tonic-gate * Precision Architecture". IEEE Transactions on Computers, Vol 37, No. 8,
557c478bd9Sstevel@tonic-gate * August 1988, page 980.
567c478bd9Sstevel@tonic-gate *
577c478bd9Sstevel@tonic-gate * Steele G.; Warren H.: Hacker's Delight. 2002 Pearson Education, Ch 10
587c478bd9Sstevel@tonic-gate *
597c478bd9Sstevel@tonic-gate */
607c478bd9Sstevel@tonic-gate
617257d1b4Sraf	ENTRY(gettimeofday)
627c478bd9Sstevel@tonic-gate	brz,pn	%o0, 1f
637c478bd9Sstevel@tonic-gate	mov	%o0, %o5
647c478bd9Sstevel@tonic-gate	SYSFASTTRAP(GETHRESTIME)
657c478bd9Sstevel@tonic-gate	stn	%o0, [%o5]
667c478bd9Sstevel@tonic-gate	sethi	%hi(0x10624DD3), %o2
677c478bd9Sstevel@tonic-gate	or	%o2, %lo(0x10624DD3), %o2
687c478bd9Sstevel@tonic-gate	mulx	%o1, %o2, %o2
697c478bd9Sstevel@tonic-gate	srlx	%o2, 38, %o2
707c478bd9Sstevel@tonic-gate	stn	%o2, [%o5 + CLONGSIZE]
717c478bd9Sstevel@tonic-gate1:	RETC
727257d1b4Sraf	SET_SIZE(gettimeofday)
73