/* 
 * Mach Operating System
 * Copyright (c) 1989 Carnegie-Mellon University
 * All rights reserved.  The CMU software License Agreement specifies
 * the terms and conditions for use and redistribution.
 */
/* 
 **********************************************************************
 * HISTORY
 * $Log:	mttoggle.s,v $
 * Revision 2.3  89/03/09  20:26:56  rpd
 * 	More cleanup.
 * 
 * Revision 2.2  89/02/26  14:14:21  gm0w
 * 	Changes for cleanup.
 * 
 **********************************************************************
 */
/*
 * Copyright (c) 1980, 1986 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#ifndef	lint
_sccsid:.asciz	"@(#)mttoggle.s	7.1 (Berkeley) 6/5/86"
#endif	not lint

/*
 * Prototype toggle in bootstrap code for mt type tapes.
 * If on anything but a 780 with a tape at drive 0 of mba 1
 * this will have to be repaired by patching mba and mt.
 */
	movl	mba,r10
	mull3	mt,$0x80,r11
	addl3	r11,r10,r11
	addl2	$0x400,r11
	movzbl	$1,4(r10)
	movzbl	$4,8(r11)		/* drive zero, one record */
	clrl	12(r10)			/* set address to zero */
	movl	$0x80000000,0x800(r10)	/* validate map register */
	cvtwl	$-512,16(r10)		/* set byte count */
	movzwl	$512,20(r11)		/* set byte count */
0:
	movl	0x44(r11),r0
	bbc	$15,r0,0b
	movzbl	$071,(r11)		/* read forward, go */
	halt
	.align	2
mba:	.long	0x20012000
mt:	.long	0
