/*      $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: