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Rev | Author | Line No. | Line |
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2455 | mario79 | 1 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
2 | ;; ;; |
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5363 | yogev_ezra | 3 | ;; Copyright (C) KolibriOS team 2004-2015. All rights reserved. ;; |
2455 | mario79 | 4 | ;; Distributed under terms of the GNU General Public License ;; |
5 | ;; ;; |
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6 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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7 | |||
796 | shurf | 8 | ; FAT12 boot sector for Kolibri OS |
9 | ; |
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10 | ; Copyright (C) Alex Nogueira Teixeira |
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11 | ; Copyright (C) Diamond |
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12 | ; Copyright (C) Dmitry Kartashov aka shurf |
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13 | ; |
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14 | ; Distributed under GPL, see file COPYING for details |
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15 | ; |
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16 | ; Version 1.0 |
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17 | |||
3274 | esevece | 18 | include "lang.inc" |
19 | |||
7136 | dunkaist | 20 | lf = 0ah |
21 | cr = 0dh |
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796 | shurf | 22 | |
7136 | dunkaist | 23 | pos_read_tmp = 0700h ;position for temporary read |
24 | boot_program = 07c00h ;position for boot code |
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25 | seg_read_kernel = 01000h ;segment to kernel read |
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796 | shurf | 26 | |
2288 | clevermous | 27 | jmp start_program |
28 | nop |
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796 | shurf | 29 | |
30 | ; Boot Sector and BPB Structure |
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31 | include 'floppy1440.inc' |
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32 | ;include 'floppy2880.inc' |
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33 | ;include 'floppy1680.inc' |
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34 | ;include 'floppy1743.inc' |
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35 | |||
36 | start_program: |
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7215 | theonlymir | 37 | ; |
38 | cld ;clear direction flag for Phoenix BIOS, see next "lodsb" |
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2288 | clevermous | 39 | xor ax, ax |
7215 | theonlymir | 40 | cli |
2288 | clevermous | 41 | mov ss, ax |
42 | mov sp, boot_program |
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7215 | theonlymir | 43 | sti |
44 | ; <\Efremenkov S.V.> |
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2288 | clevermous | 45 | push ss |
46 | pop ds |
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796 | shurf | 47 | |
2288 | clevermous | 48 | ; print loading string |
49 | mov si, loading+boot_program |
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796 | shurf | 50 | loop_loading: |
2288 | clevermous | 51 | lodsb |
52 | or al, al |
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53 | jz read_root_directory |
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54 | mov ah, 0eh |
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55 | mov bx, 7 |
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56 | int 10h |
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57 | jmp loop_loading |
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796 | shurf | 58 | |
59 | read_root_directory: |
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2288 | clevermous | 60 | push ss |
61 | pop es |
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796 | shurf | 62 | |
2288 | clevermous | 63 | ; calculate some disk parameters |
64 | ; - beginning sector of RootDir |
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65 | mov ax, word [BPB_FATSz16+boot_program] |
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66 | xor cx, cx |
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67 | mov cl, byte [BPB_NumFATs+boot_program] |
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68 | mul cx |
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69 | add ax, word [BPB_RsvdSecCnt+boot_program] |
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70 | mov word [FirstRootDirSecNum+boot_program], ax ; 19 |
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71 | mov si, ax |
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796 | shurf | 72 | |
2288 | clevermous | 73 | ; - count of sectors in RootDir |
74 | mov bx, word [BPB_BytsPerSec+boot_program] |
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75 | mov cl, 5 ; divide ax by 32 |
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76 | shr bx, cl ; bx = directory entries per sector |
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77 | mov ax, word [BPB_RootEntCnt+boot_program] |
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78 | xor dx, dx |
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79 | div bx |
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80 | mov word [RootDirSecs+boot_program], ax ; 14 |
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796 | shurf | 81 | |
2288 | clevermous | 82 | ; - data start |
83 | add si, ax ; add beginning sector of RootDir and count sectors in RootDir |
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84 | mov word [data_start+boot_program], si ; 33 |
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85 | ; reading root directory |
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86 | ; al=count root dir sectrors !!!! TODO: al, max 255 sectors !!!! |
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87 | mov ah, 2 ; read |
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88 | push ax |
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796 | shurf | 89 | |
2288 | clevermous | 90 | mov ax, word [FirstRootDirSecNum+boot_program] |
91 | call conv_abs_to_THS ; convert abs sector (AX) to BIOS T:H:S (track:head:sector) |
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92 | pop ax |
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93 | mov bx, pos_read_tmp ; es:bx read buffer |
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94 | call read_sector |
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796 | shurf | 95 | |
2288 | clevermous | 96 | mov si, bx ; read buffer address: es:si |
97 | mov ax, [RootDirSecs+boot_program] |
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98 | mul word [BPB_BytsPerSec+boot_program] |
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99 | add ax, si ; AX = end of root dir. in buffer pos_read_tmp |
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796 | shurf | 100 | |
2288 | clevermous | 101 | ; find kernel file in root directory |
796 | shurf | 102 | loop_find_dir_entry: |
2288 | clevermous | 103 | push si |
104 | mov cx, 11 |
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105 | mov di, kernel_name+boot_program |
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106 | rep cmpsb ; compare es:si and es:di, cx bytes long |
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107 | pop si |
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108 | je found_kernel_file |
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109 | add si, 32 ; next dir. entry |
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110 | cmp si, ax ; end of directory |
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111 | jb loop_find_dir_entry |
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796 | shurf | 112 | |
113 | file_error_message: |
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2288 | clevermous | 114 | mov si, error_message+boot_program |
796 | shurf | 115 | |
116 | loop_error_message: |
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2288 | clevermous | 117 | lodsb |
118 | or al, al |
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119 | jz freeze_pc |
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120 | mov ah, 0eh |
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121 | mov bx, 7 |
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122 | int 10h |
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123 | jmp loop_error_message |
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796 | shurf | 124 | |
125 | freeze_pc: |
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2288 | clevermous | 126 | jmp $ ; endless loop |
796 | shurf | 127 | |
2288 | clevermous | 128 | ; === KERNEL FOUND. LOADING... === |
796 | shurf | 129 | |
130 | found_kernel_file: |
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2288 | clevermous | 131 | mov bp, [si+01ah] ; first cluster of kernel file |
132 | mov [cluster1st+boot_program], bp ; starting cluster of kernel file |
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796 | shurf | 133 | |
2288 | clevermous | 134 | ; reading first FAT table |
135 | mov ax, word [BPB_RsvdSecCnt+boot_program] ; begin first FAT abs sector number |
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136 | call conv_abs_to_THS ; convert abs sector (AX) to BIOS T:H:S (track:head:sector) |
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137 | mov bx, pos_read_tmp ; es:bx read position |
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138 | mov ah, 2 ; ah=2 (read) |
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139 | mov al, byte [BPB_FATSz16+boot_program] ; FAT size in sectors (TODO: max 255 sectors) |
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140 | call read_sector |
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141 | jc file_error_message ; read error |
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796 | shurf | 142 | |
2288 | clevermous | 143 | mov ax, seg_read_kernel |
144 | mov es, ax |
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145 | xor bx, bx ; es:bx = 1000h:0000h |
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796 | shurf | 146 | |
147 | |||
2288 | clevermous | 148 | ; reading kernel file |
796 | shurf | 149 | loop_obtains_kernel_data: |
2288 | clevermous | 150 | ; read one cluster of file |
151 | call obtain_cluster |
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152 | jc file_error_message ; read error |
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796 | shurf | 153 | |
2288 | clevermous | 154 | ; add one cluster length to segment:offset |
155 | push bx |
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156 | mov bx, es |
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157 | mov ax, word [BPB_BytsPerSec+boot_program] ;\ |
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158 | movsx cx, byte [BPB_SecPerClus+boot_program] ; | !!! TODO: !!! |
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159 | mul cx ; | out this from loop !!! |
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160 | shr ax, 4 ;/ |
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161 | add bx, ax |
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162 | mov es, bx |
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163 | pop bx |
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796 | shurf | 164 | |
2288 | clevermous | 165 | mov di, bp |
166 | shr di, 1 |
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167 | pushf |
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168 | add di, bp ; di = bp * 1.5 |
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169 | add di, pos_read_tmp |
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170 | mov ax, [di] ; read next entry from FAT-chain |
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171 | popf |
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172 | jc move_4_right |
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173 | and ax, 0fffh |
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174 | jmp verify_end_sector |
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796 | shurf | 175 | move_4_right: |
2288 | clevermous | 176 | mov cl, 4 |
177 | shr ax, cl |
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796 | shurf | 178 | verify_end_sector: |
2288 | clevermous | 179 | cmp ax, 0ff8h ; last cluster |
180 | jae execute_kernel |
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181 | mov bp, ax |
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182 | jmp loop_obtains_kernel_data |
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796 | shurf | 183 | |
184 | execute_kernel: |
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2288 | clevermous | 185 | mov ax, 'KL' |
186 | push 0 |
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187 | pop ds |
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188 | mov si, loader_block+boot_program |
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189 | push word seg_read_kernel |
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190 | push word 0 |
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191 | retf ; jmp far 1000:0000 |
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796 | shurf | 192 | |
193 | |||
194 | ;------------------------------------------ |
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2288 | clevermous | 195 | ; loading cluster from file to es:bx |
796 | shurf | 196 | obtain_cluster: |
2288 | clevermous | 197 | ; bp - cluster number to read |
198 | ; carry = 0 -> read OK |
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199 | ; carry = 1 -> read ERROR |
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796 | shurf | 200 | |
2288 | clevermous | 201 | ; print one dot |
202 | push bx |
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203 | mov ax, 0e2eh ; ah=0eh (teletype), al='.' |
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204 | xor bh, bh |
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205 | int 10h |
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206 | pop bx |
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796 | shurf | 207 | |
1738 | clevermous | 208 | writesec: |
2288 | clevermous | 209 | ; convert cluster number to sector number |
210 | mov ax, bp ; data cluster to read |
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211 | sub ax, 2 |
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212 | xor dx, dx |
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213 | mov dl, byte [BPB_SecPerClus+boot_program] |
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214 | mul dx |
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215 | add ax, word [data_start+boot_program] |
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796 | shurf | 216 | |
2288 | clevermous | 217 | call conv_abs_to_THS ; convert abs sector (AX) to BIOS T:H:S (track:head:sector) |
796 | shurf | 218 | patchhere: |
2288 | clevermous | 219 | mov ah, 2 ; ah=2 (read) |
220 | mov al, byte [BPB_SecPerClus+boot_program] ; al=(one cluster) |
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221 | call read_sector |
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222 | retn |
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796 | shurf | 223 | ;------------------------------------------ |
224 | |||
225 | ;------------------------------------------ |
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2288 | clevermous | 226 | ; read sector from disk |
796 | shurf | 227 | read_sector: |
2288 | clevermous | 228 | push bp |
9942 | turbocat | 229 | mov bp, 20 ; try 20 times |
796 | shurf | 230 | newread: |
2288 | clevermous | 231 | dec bp |
9942 | turbocat | 232 | jnz .next |
233 | cmp ah, 02h ; if read sectors |
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2288 | clevermous | 234 | jz file_error_message |
9942 | turbocat | 235 | mov byte[write_err+boot_program], 1 ; if write sectors |
236 | jmp .ret |
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237 | .next: |
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2288 | clevermous | 238 | push ax bx cx dx |
239 | int 13h |
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240 | pop dx cx bx ax |
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241 | jc newread |
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9942 | turbocat | 242 | .ret: |
2288 | clevermous | 243 | pop bp |
244 | retn |
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9942 | turbocat | 245 | |
796 | shurf | 246 | ;------------------------------------------ |
2288 | clevermous | 247 | ; convert abs. sector number (AX) to BIOS T:H:S |
248 | ; sector number = (abs.sector%BPB_SecPerTrk)+1 |
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249 | ; pre.track number = (abs.sector/BPB_SecPerTrk) |
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250 | ; head number = pre.track number%BPB_NumHeads |
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251 | ; track number = pre.track number/BPB_NumHeads |
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252 | ; Return: cl - sector number |
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253 | ; ch - track number |
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254 | ; dl - drive number (0 = a:) |
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255 | ; dh - head number |
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796 | shurf | 256 | conv_abs_to_THS: |
2288 | clevermous | 257 | push bx |
258 | mov bx, word [BPB_SecPerTrk+boot_program] |
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259 | xor dx, dx |
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260 | div bx |
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261 | inc dx |
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262 | mov cl, dl ; cl = sector number |
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263 | mov bx, word [BPB_NumHeads+boot_program] |
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264 | xor dx, dx |
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265 | div bx |
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266 | ; !!!!!!! ax = track number, dx = head number |
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267 | mov ch, al ; ch=track number |
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268 | xchg dh, dl ; dh=head number |
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269 | mov dl, 0 ; dl=0 (drive 0 (a:)) |
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270 | pop bx |
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271 | retn |
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796 | shurf | 272 | ;------------------------------------------ |
273 | |||
3274 | esevece | 274 | if lang eq sp |
275 | loading db cr,lf,'Iniciando el sistema ',00h |
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276 | else |
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2288 | clevermous | 277 | loading db cr,lf,'Starting system ',00h |
3274 | esevece | 278 | end if |
2288 | clevermous | 279 | error_message db 13,10 |
280 | kernel_name db 'KERNEL MNT ?',cr,lf,00h |
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281 | FirstRootDirSecNum dw ? |
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282 | RootDirSecs dw ? |
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283 | data_start dw ? |
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796 | shurf | 284 | |
285 | write1st: |
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2288 | clevermous | 286 | push cs |
287 | pop ds |
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288 | mov byte [patchhere+1+boot_program], 3 ; change ah=2 to ah=3 |
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289 | mov bp, [cluster1st+boot_program] |
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290 | push 1000h |
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291 | pop es |
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292 | xor bx, bx |
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293 | call writesec |
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294 | mov byte [patchhere+1+boot_program], 2 ; change back ah=3 to ah=2 |
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295 | retf |
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296 | cluster1st dw ? |
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796 | shurf | 297 | loader_block: |
9942 | turbocat | 298 | db 1 ; +0 |
299 | dw 0 ; +1 |
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300 | dw write1st+boot_program ; +3 |
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301 | dw 0 ; +5 |
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302 | write_err: db 0 ; +7 |
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796 | shurf | 303 | |
2288 | clevermous | 304 | times 0x1fe-$ db 00h |
796 | shurf | 305 | |
2288 | clevermous | 306 | db 55h,0aah ;boot signature\Efremenkov> |