| [e16e8f2] | 1 | /* ----------------------------------------------------------------------- |
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| 2 | * |
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| 3 | * Copyright 2010-2011 Gene Cumm |
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| 4 | * |
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| 5 | * Portions from mbr.S: |
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| 6 | * Copyright 2007-2009 H. Peter Anvin - All Rights Reserved |
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| 7 | * Copyright 2009 Intel Corporation; author: H. Peter Anvin |
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| 8 | * |
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| 9 | * Permission is hereby granted, free of charge, to any person |
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| 10 | * obtaining a copy of this software and associated documentation |
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| 11 | * files (the "Software"), to deal in the Software without |
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| 12 | * restriction, including without limitation the rights to use, |
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| 13 | * copy, modify, merge, publish, distribute, sublicense, and/or |
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| 14 | * sell copies of the Software, and to permit persons to whom |
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| 15 | * the Software is furnished to do so, subject to the following |
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| 16 | * conditions: |
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| 17 | * |
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| 18 | * The above copyright notice and this permission notice shall |
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| 19 | * be included in all copies or substantial portions of the Software. |
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| 20 | * |
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| 21 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
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| 22 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES |
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| 23 | * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
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| 24 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT |
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| 25 | * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, |
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| 26 | * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
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| 27 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR |
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| 28 | * OTHER DEALINGS IN THE SOFTWARE. |
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| 29 | * |
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| 30 | * ----------------------------------------------------------------------- */ |
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| 31 | |
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| 32 | /* |
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| 33 | * handoff.S: MBR/VBR-like codeblock to display handoff data |
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| 34 | * |
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| 35 | * Displays the values of DL, DS, SI, the contents of [DS:SI] (16 bytes), |
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| 36 | * the values of ES, DI, the contents of [ES:DI] (4 bytes), scans memory for |
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| 37 | * $PnP then reports a boot failure. |
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| 38 | * |
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| 39 | * This should (hopefully) be only 8086 code |
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| 40 | */ |
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| 41 | |
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| 42 | /* |
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| 43 | * Install instructions (assuming your target is /dev/dev; file or block device): |
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| 44 | * |
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| 45 | * MBR: |
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| 46 | * dd conv=notrunc bs=440 count=1 if=handoff.bin of=/dev/dev |
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| 47 | * |
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| 48 | * VBR/PBR (should work for FAT12/16/32, ext[234]fs, btrfs): |
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| 49 | * echo -en "\0353\0130\0220" |dd conv=notrunc bs=1 count=3 of=/dev/dev |
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| 50 | * dd conv=notrunc bs=2 count=210 seek=45 if=handoff.bin of=/dev/dev |
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| 51 | */ |
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| 52 | |
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| 53 | // #define DEBUG_MARKER1 /* Insert markers in binary */ |
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| 54 | // #define DEBUG_START /* Print entry addresses at start */ |
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| 55 | // #define DEBUG_LOADE /* movw versus pop */ |
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| 56 | #define DEBUG_PNP /* Scan for $PnP and show address */ |
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| 57 | #define DEBUG_PAK /* Press Any Key before boot fail */ |
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| 58 | // #define DEBUG_ENTRY_REG /* Store (manually as pusha is 80186) registers */ |
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| 59 | // #define DEBUG_FDT /* Print the floppy descriptor table; INT 1Eh*/ |
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| 60 | |
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| 61 | #ifdef DEBUG_MARKER1 |
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| 62 | .macro ASCII_MARKER1 s:vararg |
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| 63 | .ascii \s |
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| 64 | .endm |
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| 65 | #else /* DEBUG_MARKER1 */ |
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| 66 | .macro ASCII_MARKER1 s:vararg |
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| 67 | .endm |
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| 68 | #endif /* DEBUG_MARKER1 */ |
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| 69 | |
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| 70 | #ifdef DEBUG_LOADE |
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| 71 | .macro LOADE r:req, t:req |
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| 72 | movw (es_\r), %\t |
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| 73 | .endm |
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| 74 | #else /* DEBUG_LOADE */ |
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| 75 | .macro LOADE r:req, t:req |
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| 76 | popw %\t |
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| 77 | .endm |
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| 78 | #endif /* DEBUG_LOADE */ |
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| 79 | |
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| 80 | .code16 |
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| 81 | .text |
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| 82 | |
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| 83 | entry = 0x7c00 |
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| 84 | stack = (entry) |
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| 85 | e_start = (stack) |
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| 86 | e_ax = (e_start-2) |
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| 87 | e_ss = (e_ax-2) |
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| 88 | e_sp = (e_ss-2) |
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| 89 | e_bot = (e_ss) |
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| 90 | /* Doubtful this will be used */ |
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| 91 | e0_beg = (e_bot) |
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| 92 | e0_ax = (e0_beg-2) |
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| 93 | e0_cx = (e0_ax-2) |
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| 94 | e0_dx = (e0_cx-2) |
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| 95 | e0_bx = (e0_dx-2) |
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| 96 | e0_sp = (e0_bx-2) |
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| 97 | e0_bp = (e0_sp-2) |
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| 98 | e0_si = (e0_bp-2) |
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| 99 | e0_di = (e0_si-2) |
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| 100 | e0_ds = (e0_di-2) |
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| 101 | e0_es = (e0_ds-2) |
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| 102 | e0_bot = (e0_es) |
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| 103 | es_beg = (e0_bot) /* Original register values from entry point */ |
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| 104 | es_di = (es_beg-2) |
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| 105 | es_es = (es_di-2) |
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| 106 | es_si = (es_es-2) |
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| 107 | es_ds = (es_si-2) |
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| 108 | es_bot = (es_ds) |
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| 109 | |
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| 110 | BIOS_page = 0x462 |
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| 111 | |
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| 112 | int_1e = (4*0x1e) |
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| 113 | int_1e_seg = (int_1e) |
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| 114 | int_1e_off = (int_1e+2) |
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| 115 | |
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| 116 | .globl _start |
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| 117 | _start: |
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| 118 | cli |
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| 119 | #ifdef DEBUG_ENTRY_REG |
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| 120 | movw %ax, e_ax |
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| 121 | movw %ss, e_ss |
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| 122 | movw %sp, e_sp |
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| 123 | #endif /* DEBUG_ENTRY_REG */ |
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| 124 | xorw %ax, %ax |
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| 125 | movw %ax, %ss |
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| 126 | #ifdef DEBUG_ENTRY_REG |
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| 127 | movw $e0_beg, %sp |
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| 128 | /* pushaw */ /* 80186 */ |
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| 129 | pushw %ax |
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| 130 | pushw %cx |
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| 131 | pushw %dx |
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| 132 | pushw %bx |
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| 133 | pushw %sp |
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| 134 | pushw %bp |
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| 135 | pushw %si |
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| 136 | pushw %di |
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| 137 | pushw %ds |
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| 138 | pushw %es |
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| 139 | #else /* DEBUG_ENTRY_REG */ |
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| 140 | movw $es_beg, %sp |
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| 141 | #endif /* DEBUG_ENTRY_REG */ |
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| 142 | pushw %di /* es:di -> $PnP header */ |
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| 143 | pushw %es |
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| 144 | pushw %si |
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| 145 | pushw %ds |
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| 146 | sti |
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| 147 | cld |
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| 148 | pushw %cs |
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| 149 | popw %ds |
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| 150 | |
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| 151 | #ifdef DEBUG_START |
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| 152 | pushw %dx |
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| 153 | call crlf |
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| 154 | movw $(_start),%dx /* 0x0600 mbr.ld .text address */ |
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| 155 | call wrhexw |
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| 156 | call crlf |
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| 157 | call caddr |
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| 158 | caddr: |
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| 159 | popw %dx |
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| 160 | subw $(caddr - _start), %dx |
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| 161 | call wrhexw |
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| 162 | call crlf |
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| 163 | popw %dx |
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| 164 | #endif /* DEBUG_START */ |
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| 165 | |
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| 166 | /* write DL */ |
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| 167 | pr_dl: call wrstr |
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| 168 | .ascii "DL: \0" |
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| 169 | call wrhexb |
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| 170 | /* DS */ |
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| 171 | pr_ds: call wrstr |
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| 172 | .ascii " DS: \0" |
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| 173 | LOADE ds, dx |
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| 174 | pushw %dx |
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| 175 | popw %es |
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| 176 | call wrhexw |
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| 177 | /* SI */ |
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| 178 | pr_si: call wrstr |
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| 179 | .ascii " SI: \0" |
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| 180 | LOADE si, dx |
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| 181 | pushw %dx |
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| 182 | popw %di |
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| 183 | call wrhexw |
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| 184 | call crlf |
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| 185 | /* DS:SI */ |
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| 186 | movw $16, %cx |
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| 187 | call wrhexbses |
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| 188 | call crlf |
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| 189 | |
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| 190 | /* ES */ |
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| 191 | pr_es: call wrstr |
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| 192 | .ascii "ES: \0" |
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| 193 | LOADE es, dx |
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| 194 | pushw %dx |
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| 195 | popw %es |
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| 196 | call wrhexw |
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| 197 | pr_di: call wrstr |
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| 198 | .ascii " DI: \0" |
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| 199 | LOADE di, dx |
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| 200 | pushw %dx |
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| 201 | popw %di |
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| 202 | call wrhexw |
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| 203 | call crlf |
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| 204 | /* ES:DI */ /* %es:0(%di) */ |
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| 205 | movw $4, %cx |
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| 206 | call wrhexbses |
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| 207 | |
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| 208 | #ifdef DEBUG_PNP |
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| 209 | subw $4, %si |
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| 210 | es lodsw |
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| 211 | cmpw $0x5024, %ax |
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| 212 | jne scn_pnp |
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| 213 | es lodsw |
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| 214 | cmpw $0x506E, %ax |
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| 215 | jne scn_pnp |
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| 216 | call wrstr |
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| 217 | .ascii " =$PnP\0" |
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| 218 | scn_pnp: |
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| 219 | call crlf |
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| 220 | /* $PnP Scan */ |
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| 221 | movw $0xf000, %dx |
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| 222 | pushw %dx |
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| 223 | popw %es |
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| 224 | movw $0, %si |
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| 225 | movw $0x1000, %cx |
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| 226 | /* 0x506E5024 */ |
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| 227 | movw $0x5024, %dx |
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| 228 | movw $0x506E, %bx |
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| 229 | ch_pnp: es lodsw /* Check for $PnP */ |
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| 230 | cmpw %dx, %ax |
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| 231 | jne ch_pnp_l |
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| 232 | es lodsw |
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| 233 | cmpw %bx, %ax |
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| 234 | je pr_pnp |
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| 235 | ch_pnp_l: /* Check $PnP failed; loop to next address */ |
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| 236 | addw $14, %si |
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| 237 | andw $0xFFF0, %si |
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| 238 | loopw ch_pnp |
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| 239 | jmp pnp_end |
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| 240 | pr_pnp: |
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| 241 | pushw %si |
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| 242 | call wrstr |
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| 243 | .ascii "$PnP-\0" |
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| 244 | movw %es, %dx |
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| 245 | call wrhexw |
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| 246 | movb $':, %al |
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| 247 | call wrchr |
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| 248 | popw %dx |
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| 249 | andw $0xFFF0, %dx |
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| 250 | call wrhexw |
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| 251 | #endif /* DEBUG_PNP */ |
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| 252 | call crlf |
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| 253 | pnp_end: |
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| 254 | |
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| 255 | #ifdef DEBUG_FDT |
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| 256 | /* INT 1Eh: Floppy Parameter Table Pointer */ |
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| 257 | pr_1e: call wrstr |
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| 258 | .ascii "INT 1Eh: \0" |
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| 259 | mov $int_1e,%bx |
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| 260 | les (%bx),%di |
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| 261 | pushw %es |
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| 262 | popw %dx |
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| 263 | call wrhexw |
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| 264 | movb $':, %al |
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| 265 | call wrchr |
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| 266 | pushw %di |
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| 267 | popw %dx |
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| 268 | call wrhexw |
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| 269 | call crlf |
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| 270 | /* [INT 1Eh] */ |
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| 271 | movw $14, %cx |
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| 272 | call wrhexbses |
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| 273 | call crlf |
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| 274 | #endif /* DEBUG_FDT */ |
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| 275 | |
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| 276 | end: |
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| 277 | jmp bootfail |
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| 278 | |
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| 279 | ASCII_MARKER1 "wc" |
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| 280 | wrchr: |
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| 281 | movb $0x0e, %ah |
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| 282 | movb (BIOS_page), %bh |
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| 283 | movb $0x07, %bl |
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| 284 | int $0x10 /* May destroy %bp */ |
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| 285 | ret |
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| 286 | |
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| 287 | ASCII_MARKER1 "ws" |
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| 288 | wrstr: |
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| 289 | pop %si |
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| 290 | wrstr_l: |
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| 291 | lodsb |
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| 292 | cmpb $0, %al |
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| 293 | je wrstr_d |
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| 294 | call wrchr |
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| 295 | jmp wrstr_l |
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| 296 | wrstr_d: |
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| 297 | push %si |
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| 298 | ret |
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| 299 | |
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| 300 | crlf: |
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| 301 | call wrstr |
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| 302 | .ascii "\r\n\0" |
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| 303 | ret |
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| 304 | |
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| 305 | ASCII_MARKER1 "hx" |
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| 306 | wrhexn: |
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| 307 | and $0x0F, %al |
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| 308 | cmpb $10, %al |
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| 309 | jae .alph |
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| 310 | addb $'0, %al |
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| 311 | jmp .wc |
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| 312 | .alph: |
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| 313 | addb $('A - 10), %al |
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| 314 | .wc: |
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| 315 | call wrchr |
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| 316 | ret |
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| 317 | |
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| 318 | wrhexb: |
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| 319 | pushw %cx |
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| 320 | movb %dl, %al |
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| 321 | pushw %ax |
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| 322 | movb $4, %cl |
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| 323 | rorw %cl, %ax |
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| 324 | call wrhexn |
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| 325 | popw %ax |
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| 326 | call wrhexn |
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| 327 | popw %cx |
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| 328 | ret |
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| 329 | |
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| 330 | wrhexw: |
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| 331 | pushw %cx |
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| 332 | movb $8, %cl |
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| 333 | rorw %cl, %dx |
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| 334 | call wrhexb |
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| 335 | rorw %cl, %dx |
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| 336 | call wrhexb |
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| 337 | popw %cx |
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| 338 | ret |
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| 339 | |
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| 340 | ASCII_MARKER1 "HE" |
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| 341 | wrhexbses: |
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| 342 | pushw %di |
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| 343 | popw %si |
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| 344 | wrhexbses_l: |
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| 345 | movb $' , %al |
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| 346 | call wrchr |
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| 347 | es lodsb |
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| 348 | movw %ax, %dx |
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| 349 | call wrhexb |
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| 350 | loop wrhexbses_l |
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| 351 | ret |
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| 352 | |
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| 353 | data: |
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| 354 | ASCII_MARKER1 "bf" |
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| 355 | bootfail: |
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| 356 | #ifdef DEBUG_PAK |
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| 357 | call wrstr |
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| 358 | .ascii "\r\n\r\nPress any key\r\n\0" |
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| 359 | xor %ax, %ax |
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| 360 | int $0x16 |
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| 361 | #endif |
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| 362 | int $0x18 /* Boot failure */ |
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| 363 | die: |
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| 364 | hlt |
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| 365 | jmp die |
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