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biosgetrtc.S revision 1.7 
      1 /*	$NetBSD: biosgetrtc.S,v 1.7 2011/06/16 13:27:59 joerg Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1996
      5  *	Matthias Drochner.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  *
     27  */
     28 
     29 #include <machine/asm.h>
     30 
     31 ENTRY(biosgetrtc)
     32 	pusha
     33 	pushl	%eax
     34 
     35 	xorl	%ebx, %ebx
     36 
     37 	call	_C_LABEL(prot_to_real)	# enter real mode
     38 	.code16
     39 
     40 	movb	$2, %ah
     41 	int	$0x1a
     42 	jnc	ok
     43 	movl	$-1, %ebx
     44 
     45 ok:
     46 	calll	_C_LABEL(real_to_prot) # back to protected mode
     47 	.code32
     48 
     49 	popl	%eax
     50 	movb	%ch, (%eax)
     51 	movb	%cl, 1(%eax)
     52 	movb	%dh, 2(%eax)
     53 	movb	$0,  3(%eax)
     54 
     55 	movl	%ebx, 28(%esp)
     56 
     57 	popa
     58 	ret
     59