pbr.S revision 1.2
1 /* $NetBSD: pbr.S,v 1.2 2012/01/21 19:44:30 nonaka Exp $ */ 2 3 /*- 4 * Copyright (C) 2005 NONAKA Kimihiro <nonaka (at) netbsd.org> 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 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include <machine/asm.h> 29 #include <sys/bootblock.h> 30 31 #ifdef BOOT_FROM_FAT 32 #define MBR_AFTERBPB 90 /* BPB size in FAT32 partition BR */ 33 #else 34 #define MBR_AFTERBPB 62 /* BPB size in floppy master BR */ 35 #endif 36 37 ENTRY(start) 38 bra start0 39 .byte 0x11 /* 0x4e11: cmp/pz r14... */ 40 .ascii "NetBSD20" 41 42 . = _C_LABEL(start) + MBR_BPB_OFFSET /* move to start of BPB */ 43 44 . = _C_LABEL(start) + MBR_AFTERBPB /* skip BPB */ 45 start0: 46 mova mbr_end, r0 47 mov.w mbr_size, r2 48 sub r2, r0 49 mov r0, r11 /* r11: own loaded address */ 50 51 mov.w stack_offset, r1 52 add r1, r0 53 mov r0, r15 /* r15: stack pointer */ 54 mov r0, r10 /* r10: load address */ 55 56 /* enable/flush cache */ 57 mov #0, r4 58 mov #6, r0 59 trapa #0x3f 60 61 /* Read from start of disk */ 62 mov #0x40, r4 /* LBA */ 63 mov #0, r5 /* LBA #0 */ 64 mov r10, r6 /* buffer address */ 65 bsr read_sectors_lba 66 mov #BOOTXX_SECTORS, r7 /* number of sectors */ 67 68 mov.l @r11, r1 69 mov.l @r10, r2 70 cmp/eq r1, r2 71 bt/s pbr_read_ok 72 mov #0, r9 /* r9: sector # */ 73 74 /* Search bootable partition */ 75 mov.w part_offset, r12 76 add r10, r12 /* r12: pointer to partition entry */ 77 mov #MBR_PART_COUNT, r8 /* r8: partition loop counter */ 78 loop_part: 79 mov.b @(4, r12), r0 80 #ifdef BOOT_FROM_FAT 81 cmp/eq #MBR_PTYPE_FAT12, r0 82 bt found 83 cmp/eq #MBR_PTYPE_FAT16S, r0 84 bt found 85 cmp/eq #MBR_PTYPE_FAT16B, r0 86 bt found 87 cmp/eq #MBR_PTYPE_FAT32, r0 88 bt found 89 cmp/eq #MBR_PTYPE_FAT32L, r0 90 bt found 91 cmp/eq #MBR_PTYPE_FAT16L, r0 92 bt found 93 #else 94 cmp/eq #MBR_PTYPE_NETBSD, r0 95 #endif 96 bf next_part 97 98 found: 99 /* found boot partition */ 100 mov.w @(8, r12), r0 101 mov r0, r1 102 mov.w @(10, r12), r0 103 extu.w r1, r1 104 shll16 r0 105 or r1, r0 106 tst r0, r0 107 bt next_part /* start LBA == 0 ? */ 108 109 bra boot_lba 110 mov r0, r9 111 112 next_part: 113 dt r8 114 bf/s loop_part 115 add #16, r12 116 117 ptn_error: 118 /* Not found NetBSD partition */ 119 mova ERR_PTN, r0 120 error: 121 bsr message_crlf 122 mov r0, r4 123 99: bra 99b 124 nop 125 126 read_error: 127 bra error 128 mova ERR_READ, r0 129 130 magic_error: 131 bra error 132 mova ERR_NO_BOOTXX, r0 133 134 message_crlf: 135 mov #32, r0 136 trapa #0x3f 137 mova crlf, r0 138 mov r0, r4 139 mov #32, r0 140 trapa #0x3f 141 rts 142 nop 143 144 read_sectors_lba: 145 mov #2, r0 146 trapa #0x3f 147 tst r0, r0 148 bf read_error 149 rts 150 nop 151 152 boot_lba: 153 mov #0x40, r4 /* LBA */ 154 mov r9, r5 /* LBA # */ 155 mov r10, r6 /* buffer address */ 156 bsr read_sectors_lba 157 mov #BOOTXX_SECTORS, r7 /* number of sectors */ 158 159 pbr_read_ok: 160 mov.l .L.bootxx_magic1, r1 161 mov.l .L.bootxx_magic, r2 162 mov.l @r2, r2 163 cmp/eq r1, r2 164 bf magic_error 165 166 /* flush cache */ 167 mov #0, r4 168 mov #6, r0 169 trapa #0x3f 170 171 mov.l .L.bootxx_start, r13 172 jmp @r13 /* jump to bootxx */ 173 mov r9, r4 /* pass sector address to bootxx */ 174 175 176 .align 1 177 mbr_size: .word mbr_end - _C_LABEL(start) 178 .align 1 179 stack_offset: .word 0x1000 180 .align 1 181 part_offset: .word MBR_PART_OFFSET 182 .align 1 183 magic_offset: .word MBR_MAGIC_OFFSET 184 185 .align 2 186 .L.bootxx_magic1: 187 .long LANDISK_BOOT_MAGIC_1 188 .L.bootxx_magic: 189 .long _C_LABEL(bootxx_magic) 190 .L.bootxx_start: 191 .long _C_LABEL(bootxx_start) 192 193 .align 2 194 crlf: .asciz "\r\n" 195 196 .align 2 197 ERR_READ: .asciz "Disk read" 198 .align 2 199 ERR_NO_BOOTXX: .asciz "Not a bootxx image" 200 .align 2 201 ERR_PTN: .asciz "No NetBSD partition" 202 203 204 /* space for mbr_dsn */ 205 . = _C_LABEL(start) + MBR_DSN_OFFSET 206 .long 0 207 208 /* mbr_bootsel_magic */ 209 . = _C_LABEL(start) + MBR_BS_MAGIC_OFFSET 210 .word 0 211 212 /* 213 * MBR partition table 214 */ 215 . = _C_LABEL(start) + MBR_PART_OFFSET 216 _pbr_part0: 217 .byte 0, 0, 0, 0, 0, 0, 0, 0 218 .byte 0, 0, 0, 0, 0, 0, 0, 0 219 _pbr_part1: 220 .byte 0, 0, 0, 0, 0, 0, 0, 0 221 .byte 0, 0, 0, 0, 0, 0, 0, 0 222 _pbr_part2: 223 .byte 0, 0, 0, 0, 0, 0, 0, 0 224 .byte 0, 0, 0, 0, 0, 0, 0, 0 225 _pbr_part3: 226 .byte 0, 0, 0, 0, 0, 0, 0, 0 227 .byte 0, 0, 0, 0, 0, 0, 0, 0 228 229 . = _C_LABEL(start) + MBR_MAGIC_OFFSET 230 magic: 231 .word MBR_MAGIC 232 mbr_end: 233
Indexes created Sat Oct 11 19:10:01 GMT 2025