[a6da9fb] | 1 | /*
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| 2 | * Copyright (C) 2017 The Contributors
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| 3 | *
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| 4 | * This program is free software: you can redistribute it and/or modify
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| 5 | * it under the terms of the GNU General Public License as published by
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| 6 | * the Free Software Foundation, either version 3 of the License, or (at
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| 7 | * your option) any later version.
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| 8 | *
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| 9 | * This program is distributed in the hope that it will be useful, but
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| 10 | * WITHOUT ANY WARRANTY; without even the implied warranty of
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| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 12 | * General Public License for more details.
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| 13 | *
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| 14 | * A copy of the GNU General Public License can be found in the file
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| 15 | * "gpl.txt" in the top directory of this repository.
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| 16 | */
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| 17 |
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| 18 | #include <stdbool.h>
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| 19 | #include <stddef.h>
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| 20 | #include <stdint.h>
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| 21 | #include <stdio.h>
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| 22 | #include <stdlib.h>
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| 23 | #include <string.h>
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| 24 |
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| 25 | #include <sys/types.h>
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| 26 |
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| 27 | #define DISK_FILE_NAME "buchla.disk"
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| 28 | #define MIDAS_FILE_NAME "midas.abs"
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| 29 |
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| 30 | #define N_CYL 80
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| 31 | #define N_SID 2
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| 32 | #define N_SEC 18
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| 33 | #define SZ_SEC 512
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| 34 |
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| 35 | #define N_SEC_CLU 1
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| 36 |
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| 37 | #define N_BOOT_SEC 1
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| 38 | #define N_FAT_SEC 9
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| 39 | #define N_ROOT_SEC 14
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| 40 |
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| 41 | #define N_FAT 2
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| 42 | #define SZ_DIR_ENT 32
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| 43 |
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| 44 | #define ROOT_SEC (N_BOOT_SEC + N_FAT_SEC * N_FAT)
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| 45 | #define N_META_SEC (ROOT_SEC + N_ROOT_SEC)
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| 46 |
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| 47 | static uint8_t midas[1024 * 1024];
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| 48 | static int32_t sz_midas;
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| 49 |
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| 50 | static uint8_t disk[N_CYL * N_SID * N_SEC][SZ_SEC];
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| 51 |
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| 52 | static int32_t put_sec_8(int32_t sec, int32_t off, int32_t val)
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| 53 | {
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| 54 | disk[sec][off] = (uint8_t)val;
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| 55 | return off + 1;
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| 56 | }
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| 57 |
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| 58 | static int32_t put_sec_16(int32_t sec, int32_t off, int32_t val)
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| 59 | {
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| 60 | disk[sec][off + 0] = (uint8_t)(val >> 0);
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| 61 | disk[sec][off + 1] = (uint8_t)(val >> 8);
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| 62 | return off + 2;
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| 63 | }
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| 64 |
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| 65 | static int32_t put_sec_32(int32_t sec, int32_t off, int32_t val)
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| 66 | {
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| 67 | off = put_sec_16(sec, off, val & 65535);
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| 68 | off = put_sec_16(sec, off, val >> 16);
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| 69 | return off;
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| 70 | }
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| 71 |
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| 72 | static int32_t put_sec_str(int32_t sec, int32_t off, const char *str, int32_t len)
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| 73 | {
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| 74 | int32_t i;
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| 75 |
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| 76 | for (i = 0; str[i] != 0 && i < len; ++i) {
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| 77 | disk[sec][off + i] = (uint8_t)str[i];
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| 78 | }
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| 79 |
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| 80 | while (i < len) {
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| 81 | disk[sec][off + i] = ' ';
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| 82 | ++i;
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| 83 | }
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| 84 |
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| 85 | return off + i;
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| 86 | }
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| 87 |
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| 88 | static int32_t put_fat_12(int32_t sec, int32_t ent, int32_t val)
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| 89 | {
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| 90 | uint8_t *fat = disk[sec];
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| 91 |
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| 92 | int32_t off = ent / 2 * 3;
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| 93 | int32_t bit = (ent % 2) * 12;
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| 94 |
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| 95 | int32_t tmp = 0;
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| 96 |
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| 97 | tmp |= fat[off + 0] << 0;
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| 98 | tmp |= fat[off + 1] << 8;
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| 99 | tmp |= fat[off + 2] << 16;
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| 100 |
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| 101 | tmp = (tmp & ~(0xfff << bit)) | (val << bit);
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| 102 |
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| 103 | fat[off + 0] = (uint8_t)(tmp >> 0);
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| 104 | fat[off + 1] = (uint8_t)(tmp >> 8);
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| 105 | fat[off + 2] = (uint8_t)(tmp >> 16);
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| 106 |
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| 107 | return ent + 1;
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| 108 | }
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| 109 |
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| 110 | static void init_boot_sector(void)
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| 111 | {
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| 112 | int32_t off = 0;
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| 113 |
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| 114 | // magic number
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| 115 | off = put_sec_8(0, off, 0xe9);
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| 116 | off = put_sec_8(0, off, 0x00);
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| 117 |
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| 118 | // OEM
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| 119 | off = put_sec_str(0, off, "EMUL", 6);
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| 120 |
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| 121 | // serial number
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| 122 | off = put_sec_8(0, off, 0x01);
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| 123 | off = put_sec_8(0, off, 0x02);
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| 124 | off = put_sec_8(0, off, 0x03);
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| 125 |
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| 126 | // bytes per sector
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| 127 | off = put_sec_16(0, off, SZ_SEC);
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| 128 |
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| 129 | // sectors per cluster
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| 130 | off = put_sec_8(0, off, N_SEC_CLU);
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| 131 |
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| 132 | // number of reserved sectors
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| 133 | off = put_sec_16(0, off, N_BOOT_SEC);
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| 134 |
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| 135 | // number of FATs
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| 136 | off = put_sec_8(0, off, N_FAT);
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| 137 |
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| 138 | // maximum number of root directory entries
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| 139 | off = put_sec_16(0, off, N_ROOT_SEC * SZ_SEC / SZ_DIR_ENT);
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| 140 |
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| 141 | // total number of sectors
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| 142 | off = put_sec_16(0, off, N_CYL * N_SID * N_SEC);
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| 143 |
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| 144 | // media descriptor (floppy disk, 1.44M)
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| 145 | off = put_sec_8(0, off, 0xf0);
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| 146 |
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| 147 | // sectors per FAT (9 * 512 / 3 * 2 = 3072)
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| 148 | off = put_sec_16(0, off, N_FAT_SEC);
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| 149 |
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| 150 | // sectors per track
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| 151 | off = put_sec_16(0, off, N_SEC);
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| 152 |
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| 153 | // number of sides
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| 154 | off = put_sec_16(0, off, N_SID);
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| 155 |
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| 156 | // number of hidden sectors
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| 157 | off = put_sec_16(0, off, 0);
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| 158 |
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| 159 | put_sec_8(0, SZ_SEC - 2, 0x55);
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| 160 | put_sec_8(0, SZ_SEC - 1, 0xaa);
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| 161 | }
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| 162 |
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| 163 | static void init_fat(int32_t sec)
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| 164 | {
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| 165 | int32_t ent = 0;
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| 166 |
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| 167 | ent = put_fat_12(sec, ent, 0xff0);
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| 168 | ent = put_fat_12(sec, ent, 0xfff);
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| 169 |
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| 170 | int32_t n_sec = (sz_midas + SZ_SEC - 1) / SZ_SEC;
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| 171 |
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| 172 | for (int32_t i = 0; i < n_sec - 1; ++i) {
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| 173 | ent = put_fat_12(sec, ent, ent + 1);
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| 174 | }
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| 175 |
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| 176 | put_fat_12(sec, ent, 0xfff);
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| 177 | }
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| 178 |
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| 179 | static void init_midas(void)
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| 180 | {
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| 181 | int32_t off = 0;
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| 182 |
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| 183 | // file name
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| 184 | off = put_sec_str(ROOT_SEC, off, "MIDAS", 8);
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| 185 |
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| 186 | // extension
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| 187 | off = put_sec_str(ROOT_SEC, off, "ABS", 3);
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| 188 |
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| 189 | // file attributes (0x20 = archive)
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| 190 | off = put_sec_8(ROOT_SEC, off, 0x20);
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| 191 |
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| 192 | // unused
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| 193 | for (int32_t i = 0; i < 10; ++i) {
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| 194 | off = put_sec_8(ROOT_SEC, off, 0x00);
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| 195 | }
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| 196 |
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| 197 | // last modified time (12:34:56)
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| 198 | off = put_sec_16(ROOT_SEC, off, (12 << 11) | (34 << 5) | (56 / 2));
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| 199 |
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| 200 | // last modified date (1988-06-20)
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| 201 | off = put_sec_16(ROOT_SEC, off, (8 << 9) | (6 << 5) | 20);
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| 202 |
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| 203 | // start cluster
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| 204 | off = put_sec_16(ROOT_SEC, off, 2);
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| 205 |
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| 206 | // file size
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| 207 | off = put_sec_32(ROOT_SEC, off, sz_midas);
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| 208 |
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| 209 | int32_t n_sec = (sz_midas + SZ_SEC - 1) / SZ_SEC;
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| 210 | memcpy(disk[N_META_SEC], midas, (size_t)n_sec * SZ_SEC);
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| 211 | }
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| 212 |
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| 213 | static void write_disk(void)
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| 214 | {
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| 215 | FILE *fh = fopen(DISK_FILE_NAME, "wb");
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| 216 |
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| 217 | if (fh == NULL || fwrite(disk, sizeof disk, 1, fh) != 1) {
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| 218 | fprintf(stderr, "error while writing disk file " DISK_FILE_NAME "\n");
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| 219 | exit(1);
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| 220 | }
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| 221 |
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| 222 | fclose(fh);
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| 223 | }
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| 224 |
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| 225 | static void load_midas(void)
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| 226 | {
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| 227 | FILE *fh = fopen(MIDAS_FILE_NAME, "rb");
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| 228 |
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| 229 | if (fh == NULL) {
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| 230 | fprintf(stderr, "error while opening MIDAS file " MIDAS_FILE_NAME "\n");
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| 231 | exit(1);
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| 232 | }
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| 233 |
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| 234 | if (fseek(fh, 0, SEEK_END) < 0) {
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| 235 | fprintf(stderr, "error while seeking in MIDAS file " MIDAS_FILE_NAME "\n");
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| 236 | exit(1);
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| 237 | }
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| 238 |
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| 239 | ssize_t len = ftell(fh);
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| 240 |
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| 241 | if (len < 0) {
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| 242 | fprintf(stderr, "error while determining size of MIDAS file " MIDAS_FILE_NAME "\n");
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| 243 | exit(1);
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| 244 | }
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| 245 |
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| 246 | sz_midas = (int32_t)len;
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| 247 | rewind(fh);
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| 248 |
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| 249 | if (fread(midas, (size_t)sz_midas, 1, fh) != 1) {
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| 250 | fprintf(stderr, "error while reading MIDAS file " MIDAS_FILE_NAME "\n");
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| 251 | exit(1);
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| 252 | }
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| 253 |
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| 254 | fclose(fh);
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| 255 | }
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| 256 |
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| 257 | int32_t main(int32_t argc, char *argv[])
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| 258 | {
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| 259 | (void)argc;
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| 260 | (void)argv;
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| 261 |
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| 262 | load_midas();
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| 263 | init_boot_sector();
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| 264 |
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| 265 | for (int32_t i = 0; i < N_FAT; ++i) {
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| 266 | init_fat(N_BOOT_SEC + i * N_FAT_SEC);
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| 267 | }
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| 268 |
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| 269 | init_midas();
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| 270 | write_disk();
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| 271 | return 0;
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| 272 | }
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