xref: /src/sys/arch/atari/stand/xxboot/ahdi-xxboot/xxboot.ahdi.S

/*	$NetBSD: xxboot.ahdi.S,v 1.3 2022/06/26 14:14:46 tsutsui Exp $	*/

/*
 * Copyright (c) 1995 Waldi Ravens.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *        This product includes software developed by Waldi Ravens.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "xxboot.h"

	.globl	_start, main, fill

	.text

_start:	bras	main
/*
 * Fake gemdos-fs bootsector, to keep TOS away.
 */
	.ascii	"NetBSD"	| oem
	.byte	0,0,0		| serial
	.word	0		| bps
	.byte	0		| spc
	.word	0		| res
	.byte	0		| fat
	.word	0		| ndirs
	.word	0		| sec
	.byte	0		| media
	.word	0		| spf
	.word	0		| spt
	.word	0		| side
	.word	0		| hid
	.even
/*
 * AHDI rootsector code passes:
 * d3: SCSI/IDE <-> ACSI flag	d4: SCSI/IDE target (or -1)
 * d5: boot preference		d6: offset of boot block
 * d7: ACSI target		a3: pointer to readsector()
 * a4: pointer to `start'	a5: pointer to back-to-ROM
 */
main:	movml	%d3-%d7/%a3-%a5,%sp@-
	lea	%pc@(regsav),%a0
	movl	%sp,%a0@

	movw	#-1,%sp@-
	movw	#Kbshift,%sp@-
	trap	#BIOS
	addql	#4,%sp
	subql	#1,%d0
	movl	%d0,%a5			| autoboot flag

	lea	%pc@(m_bot),%a6
	movl	_membot:w,%d3
	lea	MAXBOT,%a4
	cmpl	%a4,%d3
	bhis	exit			| membot > MAXBOT

	lea	%pc@(m_top),%a6
	movl	_memtop:w,%d3
	cmpl	#MINTOP,%d3
	blts	exit			| memtop < MINTOP

	andw	#-4,%d3
	movl	%d3,%a0
	movl	%sp,%a0@-
	movl	%a0,%sp			| set new stack
/*
 * Load secondary boot loader and disklabel.
 */
	movml	%a4/%a5,%sp@-
	movq	#NSEC,%d3		| # of sectors
	addql	#1,%d6			| first sector
	bsr	rds1
	lea	%pc@(m_rds),%a6
	movml	%sp@+,%a4/%a5
	bnes	0f			| I/O error
/*
 * int bootxx(readsector, disklabel, autoboot)
 */
	pea	%a5@			| autoboot
	pea	%a4@(LBLST-MAXBOT)	| disklabel
	pea	%pc@(rds2)		| readsector
	jsr	%a4@(BXXST-MAXBOT)
	lea	%pc@(m_sbl),%a6		| NetBSD not booted
	lea	%sp@(12),%sp

0:	movl	%sp@,%sp			| restore BIOS stack
	movl	%d0,%d3
	bmis	exit
	movml	%sp@+,%d3-%d7/%a3-%a5
	movl	%d0,%d5			| new boot preference
	jmp	%a4@(-0x200)

exit:	bsrs	puts			| display error
	lea	%pc@(m_key),%a6
	bsrs	puts			| wait for key
	movml	%sp@+,%d3-%d7/%a3-%a5
	jmp	%a5@

/*
 * puts (in: a6, d3)
 */
0:	cmpw	#35,%d0		| '#'
	bnes	1f
	bsrs	puti
	bras	puts
1:	cmpw	#64,%d0		| '@'
	bnes	2f
	movw	#2,%sp@-
	movw	#Bconin,%sp@-
	trap	#BIOS
	addql	#4,%sp
	bras	puts
2:	bsrs	putc
puts:	movq	#0,%d0
	movb	%a6@+,%d0
	bnes	0b
	rts

puti:	swap	%d3
	bsrs	0f
	swap	%d3
0:	rorw	#8,%d3
	bsrs	1f
	rorw	#8,%d3
1:	rorb	#4,%d3
	bsrs	2f
	rorb	#4,%d3
2:	movw	%d3,%d0
	andw	#15,%d0
	addw	#48,%d0
	cmpw	#58,%d0
	bcss	putc
	addw	#39,%d0
putc:	movw	%d0,%sp@-
	movw	#2,%sp@-
	movw	#Bconout,%sp@-
	trap	#BIOS
	addql	#6,%sp
	rts
/*
 * int readsec (void *buffer, u_int offset, u_int count);
 */
rds2:	movml	%d2-%d7/%a2-%a6,%sp@-
	movl	%pc@(regsav),%a0
	movml	%a0@,%d3-%d7/%a3-%a5
	movl	%sp@(48),%a4		| buffer
	movl	%sp@(52),%d6		| offset
	movl	%sp@(56),%d3		| count
	bsrs	rds1
	movml	%sp@+,%d2-%d7/%a2-%a6
	rts

rds1:	movl	#255,%d5
	cmpl	%d5,%d3
	bccs	0f
	movl	%d3,%d5
0:	jsr	%a3@
	tstl	%d0
	bnes	1f
	addl	#(255*512),%a4
	addl	%d5,%d6
	subl	%d5,%d3
	bnes	rds1
1:	rts

m_bot:	.asciz	"xxboot: membot == 0x#\r\n"
m_top:	.asciz	"xxboot: memtop == 0x#\r\n"
m_sbl:	.asciz	"xxboot: bootxx => 0x#\r\n"
m_rds:	.asciz	"xxboot: Floprd => 0x#\r\n"
m_key:	.asciz	"\007\r\npress any key... @\r\n"

regsav:	.long	0

fill:	.space	54		| 510-(fill-start)
	.word	0		| checksum
end: