223 lines
4.4 KiB
ArmAsm
223 lines
4.4 KiB
ArmAsm
/* $NetBSD: mbr.S,v 1.1 2006/09/01 21:26:19 uwe Exp $ */
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/*-
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* Copyright (c) 2005 NONAKA Kimihiro
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <machine/asm.h>
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#include <sys/bootblock.h>
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ENTRY(start)
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mova mbr_end, r0
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mov r0, r11 /* r11: relocate address */
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mov.w mbr_size, r2
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sub r2, r0
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mov r0, r10 /* r10: loaded address */
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mov.w stack_offset, r1
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add r1, r0
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mov r0, r15 /* r15: stack pointer */
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/* relocate code */
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mova jmp_start, r0
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mov r0, r13
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add r2, r13 /* calc jump address */
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mov r10, r0
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mov r11, r1
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1: mov.b @r0+, r3
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dt r2
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mov.b r3, @r1
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bf/s 1b
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add #1, r1
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jmp @r13
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nop
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.align 2
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jmp_start:
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/* enable cache */
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mov #0, r4
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mov #6, r0
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trapa #0x3f
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#ifndef NO_BANNER
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/* print banner */
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mova banner, r0
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bsr message_crlf
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mov r0, r4
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#endif
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/* search bootable partition */
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mov.w part_offset, r12
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add r11, r12 /* r12: pointer to partition entry */
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mov #MBR_PART_COUNT, r8 /* r8: partition loop counter */
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loop_part:
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mov.b @(4, r12), r0
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cmp/eq #MBR_PTYPE_UNUSED, r0
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bt next_part
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/* check active partition */
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mov.b @(0, r12), r0
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cmp/eq #0x80, r0
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bf next_part
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/* found bootable partition */
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mov.w @(8, r12), r0 /* load unaligned 32bit data */
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mov r0, r1
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mov.w @(10, r12), r0
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extu.w r1, r1
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shll16 r0
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or r1, r0
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mov r0, r3
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mova found_sector, r0
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bra boot_lba
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mov.l r3, @r0
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next_part:
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dt r8
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bf/s loop_part
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add #16, r12
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noos_error:
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/* Not found bootable partition */
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mova ERR_NOOS, r0
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error:
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bsr message_crlf
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mov r0, r4
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99: bra 99b
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nop
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read_error:
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bra error
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mova ERR_READ, r0
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message_crlf:
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mov #32, r0
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trapa #0x3f
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mova crlf, r0
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mov r0, r4
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mov #32, r0
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trapa #0x3f
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rts
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nop
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read_sector_lba:
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mov #1, r7
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mov #2, r0
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trapa #0x3f
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tst r0, r0
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bf read_error
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rts
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nop
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boot_lba:
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/* read PBR sector */
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mova found_sector, r0
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mov #0x40, r4
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mov.l @r0, r5
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bsr read_sector_lba
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mov r10, r6
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/* flush cache */
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mov #0, r4
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mov #6, r0
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trapa #0x3f
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/* check signature */
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mov.b @(0, r10), r0
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tst r0, r0
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bt noos_error /* first byte non-zero */
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mov.w magic_offset, r0
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mov.w @(r0, r10), r1
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mov.w magic, r2
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cmp/eq r1, r2
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bf noos_error /* magic */
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/* now jump to PBR */
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mov r10, r0
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jmp @r10
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nop
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.align 1
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mbr_size: .word mbr_end - _C_LABEL(start)
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.align 1
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stack_offset: .word 0x1000
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.align 1
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part_offset: .word MBR_PART_OFFSET
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.align 1
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magic_offset: .word MBR_MAGIC_OFFSET
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.align 2
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found_sector: .long 0
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#ifndef NO_BANNER
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.align 2
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banner: .asciz "\r\nNetBSD MBR boot"
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#endif
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.align 2
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crlf: .asciz "\r\n"
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.align 2
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ERR_INVPART: .asciz "No active partition"
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.align 2
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ERR_READ: .asciz "Disk read error"
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.align 2
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ERR_NOOS: .asciz "No operating system"
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/* space for mbr_dsn */
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. = _C_LABEL(start) + MBR_DSN_OFFSET
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.long 0
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/* mbr_bootsel_magic */
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. = _C_LABEL(start) + MBR_BS_MAGIC_OFFSET
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.word MBR_BS_MAGIC
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/*
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* MBR partition table
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*/
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. = _C_LABEL(start) + MBR_PART_OFFSET
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_pbr_part0:
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.byte 0, 0, 0, 0, 0, 0, 0, 0
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.byte 0, 0, 0, 0, 0, 0, 0, 0
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_pbr_part1:
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.byte 0, 0, 0, 0, 0, 0, 0, 0
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.byte 0, 0, 0, 0, 0, 0, 0, 0
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_pbr_part2:
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.byte 0, 0, 0, 0, 0, 0, 0, 0
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.byte 0, 0, 0, 0, 0, 0, 0, 0
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_pbr_part3:
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.byte 0, 0, 0, 0, 0, 0, 0, 0
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.byte 0, 0, 0, 0, 0, 0, 0, 0
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. = _C_LABEL(start) + MBR_MAGIC_OFFSET
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magic:
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.word MBR_MAGIC
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mbr_end:
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