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biosgetrtc.S revision 1.1 
      1 /*	$NetBSD: biosgetrtc.S,v 1.1 1997/03/14 02:40:32 perry 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  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed for the NetBSD Project
     18  *	by Matthias Drochner.
     19  * 4. The name of the author may not be used to endorse or promote products
     20  *    derived from this software without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     32  *
     33  */
     34 
     35 #include <machine/asm.h>
     36 
     37 #define	addr32	.byte 0x67
     38 #define	data32	.byte 0x66
     39 
     40 ENTRY(biosgetrtc)
     41 	pushl	%ebp
     42 	movl	%esp, %ebp
     43 	pushl	%ebx
     44 	pushl	%ecx
     45 	pushl	%edx
     46 	push	%esi
     47 	push	%edi
     48 
     49 	xorl	%ebx, %ebx
     50 
     51 	call	_C_LABEL(prot_to_real)	# enter real mode
     52 
     53 	movb	$2, %ah
     54 	int	$0x1a
     55 	jnc	ok
     56 	movl	$-1, %ebx
     57 
     58 ok:
     59 	data32
     60 	call	_C_LABEL(real_to_prot) # back to protected mode
     61 
     62 	movl	8(%ebp), %eax
     63 	movl	$0, (%eax)
     64 	movb	%ch, (%eax)
     65 	movb	%cl, 1(%eax)
     66 	movb	%dh, 2(%eax)
     67 
     68 	movl	%ebx, %eax
     69 
     70 	pop	%edi
     71 	pop	%esi
     72 	popl	%edx
     73 	popl	%ecx
     74 	popl	%ebx
     75 	popl	%ebp
     76 	ret
     77