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      1 /*	$NetBSD: wdb00t.ahdi.S,v 1.3 2022/06/26 14:14:46 tsutsui Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1995 Waldi Ravens
      5  * 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 by Waldi Ravens.
     18  * 4. The name of the author may not be used to endorse or promote products
     19  *    derived from this software without specific prior written permission
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     31  */
     32 
     33 #include "xxboot.h"
     34 
     35 	.globl	_start, main, fill
     36 
     37 	.text
     38 
     39 _start:	bras	main
     40 	bra	rds0
     41 
     42 main:	bclr	#2,(_drvbits+3):w
     43 	clrl	pun_ptr:w
     44 	movml	%d3/%d5,%sp@-
     45 	movw	#-1,%sp@-
     46 	movw	#Kbshift,%sp@-
     47 	trap	#BIOS
     48 	addql	#4,%sp
     49 	btst	#3,%d0			| Alternate?
     50 	bnes	exit
     51 	movq	#3,%d0
     52 	lea	%pc@(p0_dsc),%a0
     53 	movb	%d5,%d1			| NVRAM bootpref
     54 	bnes	0f
     55 
     56 	| The Hades bios does not provide a bootprev. In case
     57 	| of doubt, we fetch it ourselves.
     58 	movb	#BOOTPREF,rtcrnr:w
     59 	movb	rtcdat:w,%d1
     60 	bnes	0f
     61 	movq	#-8,%d1	 		| bootpref = any
     62 
     63 0:	movb	%a0@,%d2			| bootflags
     64 	btst	#0,%d2
     65 	beqs	1f
     66 	andb	%d1,%d2
     67 	bnes	boot
     68 1:	lea	%a0@(12),%a0
     69 	dbra	%d0,0b
     70 
     71 exit:	movml	%sp@+,%d3/%d5
     72 tostst:	clrw	_bootdev:w
     73 	movl	_sysbase:w,%a0
     74 	movl	%a0@(24),%d0
     75 	swap	%d0
     76 	cmpl	#0x19870422,%d0		| old TOS?
     77 	bccs	0f			| no
     78 	movw	#0xe0,%d7
     79 0:	rts
     80 
     81 boot:	movl	%a0@(4),%d6
     82 	movq	#1,%d5
     83 	lea	%pc@(end),%a4
     84 	bsrs	rds0
     85 	tstw	%d0
     86 	bnes	exit
     87 	movl	%a4,%a0
     88 	movw	#0xff,%d0
     89 	movq	#0,%d1
     90 0:	addw	%a0@+,%d1
     91 	dbra	%d0,0b
     92 	cmpw	#0x1234,%d1
     93 	bnes	exit
     94 	lea	%pc@(rds0),%a3
     95 	lea	%pc@(tostst),%a5
     96 	movml	%sp@+,%d3/%d5
     97 	jmp	%a4@			| start bootsector code
     98 /*
     99  * in:  d4 (target) d5 (count), d6 (offset), a4 (buffer)
    100  * out: d0 (<= 0)
    101  * mod: d0, d1, d2, a0, a1, a5, a6
    102  */
    103 rds0:	lea	%pc@(dpar),%a6
    104 	tstb	%a6@
    105 	bnes	0f
    106 	movb	%d4,%d0
    107 	andb	#1,%d0
    108 	aslb	#4,%d0
    109 	orb	#0xa0,%d0
    110 	movb	%d0,idesdh:l
    111 	movl	%a4,%a0
    112 	movq	#0,%d1
    113 	movb	#0,idedor:l
    114 	movb	#0xec,idecr:l		| IDENTIFY DRIVE
    115 	bsrs	wait
    116 	bnes	err
    117 	movb	%a4@(7),%a6@		| tracks/cylinder
    118 	movb	%a4@(13),%a6@(1)		| sectors/track
    119 0:	movl	%d6,%d1
    120 	movq	#0,%d0
    121 	movb	%a6@(1),%d0
    122 	movq	#0,%d2
    123 	movb	%a6@,%d2
    124 	mulu	%d0,%d2
    125 	divu	%d2,%d1
    126 	movb	%d1,idecl:l
    127 	lsrl	#8,%d1
    128 	movb	%d1,idech:l
    129 	lsrl	#8,%d1
    130 	divu	%d0,%d1
    131 	movb	%d4,%d0
    132 	andb	#1,%d0
    133 	aslb	#4,%d0
    134 	orb	%d0,%d1
    135 	orb	#0xa0,%d1
    136 	movb	%d1,idesdh:l
    137 	swap	%d1
    138 	addqw	#1,%d1
    139 	movb	%d1,idesn:l
    140 	movl	%a4,%a0
    141 	movb	%d5,idesc:l
    142 	movw	%d5,%d1
    143 	subqw	#1,%d1
    144 	movb	#0,idedor:l
    145 	movb	#0x20,idecr:l
    146 wait:	movl	#0x7d0,%d0
    147 	addl	_hz_200:w,%d0
    148 2:	btst	#5,gpip:w
    149 	beqs	3f
    150 	cmpl	_hz_200:w,%d0
    151 	bhis	2b
    152 err:	movq	#-1,%d0
    153 	rts
    154 3:	movb	idesr:l,%d0
    155 	btst	#0,%d0
    156 	bnes	err
    157 	btst	#3,%d0
    158 	beqs	err
    159 	movq	#63,%d0
    160 	lea	idedr:l,%a1
    161 4:	movw	%a1@,%a0@+
    162 	movw	%a1@,%a0@+
    163 	movw	%a1@,%a0@+
    164 	movw	%a1@,%a0@+
    165 	dbra	%d0,4b
    166 	dbra	%d1,wait
    167 	movq	#0,%d0
    168 	rts
    169 
    170 fill:	.space	52
    171 
    172 dpar:	.byte	0			| tracks/cylinder
    173 	.byte	0			| sectors/track
    174 	.ascii	"NetBSD"
    175 hd_siz:	.long	0
    176 p0_dsc:	.long	0, 0, 0
    177 p1_dsc:	.long	0, 0, 0
    178 p2_dsc:	.long	0, 0, 0
    179 p3_dsc:	.long	0, 0, 0
    180 bsl_st:	.long	0
    181 bsl_sz:	.long	0
    182 	.word	0
    183 end:
    184