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/* $OpenBSD: pbr.S,v 1.1 2006/11/08 17:46:56 deraadt Exp $ */
/* $NetBSD: pbr.S,v 1.1 2006/09/01 21:26:19 uwe Exp $ */
/*-
* Copyright (c) 2005 NONAKA Kimihiro
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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 <machine/asm.h>
#ifdef BOOT_FROM_FAT
#define MBR_AFTERBPB 90 /* BPB size in FAT32 partition BR */
#else
#define MBR_AFTERBPB 62 /* BPB size in floppy master BR */
#endif
ENTRY(start)
bra start0
.byte 0x11 /* 0x4f11: cmp/pz r15... */
.asciz "OpenBSD"
. = _C_LABEL(start) + 0x0b /* move to start of BPB */
. = _C_LABEL(start) + 0x1c /* skip BPB */
start0:
mova pbr_end, r0
mov.w pbr_size, r2
sub r2, r0
mov r0, r11 /* r11: own loaded address */
mov.w stack_offset, r1
add r1, r0
mov r0, r15 /* r15: stack pointer */
mov r0, r10 /* r10: load address */
/* enable/flush cache */
mov #0, r4
mov #6, r0
trapa #0x3f
/* Read from start of disk */
mov #0x40, r4 /* LBA */
mov #0, r5 /* LBA #0 */
mov r10, r6 /* buffer address */
bsr read_sectors_lba
mov #XXBOOT_SECTORS, r7 /* number of sectors */
mov.l @r11, r1
mov.l @r10, r2
cmp/eq r1, r2
bt/s pbr_read_ok
mov #0, r9 /* r9: sector # */
/* Search bootable partition */
mov.w part_offset, r12
add r10, r12 /* r12: pointer to partition entry */
mov #4, r8 /* r8: partition loop counter */
loop_part:
mov.b @(4, r12), r0
#ifdef BOOT_FROM_FAT
cmp/eq #MBR_PTYPE_FAT12, r0
bt found
cmp/eq #MBR_PTYPE_FAT16S, r0
bt found
cmp/eq #MBR_PTYPE_FAT16B, r0
bt found
cmp/eq #MBR_PTYPE_FAT32, r0
bt found
cmp/eq #MBR_PTYPE_FAT32L, r0
bt found
cmp/eq #MBR_PTYPE_FAT16L, r0
bt found
#else
cmp/eq #0xa6, r0
#endif
bf next_part
found:
/* found boot partition */
mov.w @(8, r12), r0
mov r0, r1
mov.w @(10, r12), r0
extu.w r1, r1
shll16 r0
or r1, r0
tst r0, r0
bt next_part /* start LBA == 0 ? */
bra boot_lba
mov r0, r9
next_part:
dt r8
bf/s loop_part
add #16, r12
ptn_error:
/* Not found NetBSD partition */
mova ERR_PTN, r0
error:
bsr message_crlf
mov r0, r4
99: bra 99b
nop
read_error:
bra error
mova ERR_READ, r0
magic_error:
bra error
mova ERR_NO_XXBOOT, r0
message_crlf:
mov #32, r0
trapa #0x3f
mova crlf, r0
mov r0, r4
mov #32, r0
trapa #0x3f
rts
nop
read_sectors_lba:
mov #2, r0
trapa #0x3f
tst r0, r0
bf read_error
rts
nop
boot_lba:
mov #0x40, r4 /* LBA */
mov r9, r5 /* LBA # */
mov r10, r6 /* buffer address */
bsr read_sectors_lba
mov #XXBOOT_SECTORS, r7 /* number of sectors */
pbr_read_ok:
mov.l .L.xxboot_magic1, r1
mov.l .L.xxboot_magic, r2
mov.l @r2, r2
cmp/eq r1, r2
bf magic_error
/* flush cache */
mov #0, r4
mov #6, r0
trapa #0x3f
mov.l .L.xxboot_start, r13
jmp @r13 /* jump to xxboot */
mov r9, r4 /* pass sector address to xxboot */
.align 1
pbr_size: .word pbr_end - _C_LABEL(start)
.align 1
stack_offset: .word 0x1000
.align 1
part_offset: .word 0x1be
.align 1
magic_offset: .word 0x1fe
.align 2
.L.xxboot_magic1:
.long 0x20031125
.L.xxboot_magic:
.long _C_LABEL(xxboot_magic)
.L.xxboot_start:
.long _C_LABEL(xxboot_start)
.align 2
crlf: .asciz "\r\n"
.align 2
ERR_READ: .asciz "Disk read"
.align 2
ERR_NO_XXBOOT: .asciz "Not a xxboot image"
.align 2
ERR_PTN: .asciz "No OpenBSD partition"
. = _C_LABEL(start) + 0x1fe
magic:
.word 0xaa55
pbr_end:
.global _C_LABEL(ptn_disklabel)
_C_LABEL(ptn_disklabel):
.fill 512
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