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Rev | Author | Line No. | Line |
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2465 | Serge | 1 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
2 | ;; ;; |
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5565 | serge | 3 | ;; Copyright (C) KolibriOS team 2004-2015. All rights reserved. ;; |
2465 | Serge | 4 | ;; Distributed under terms of the GNU General Public License ;; |
5 | ;; ;; |
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6 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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7 | |||
2434 | Serge | 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 | |||
3500 | Serge | 18 | include "lang.inc" |
19 | |||
2434 | Serge | 20 | lf equ 0ah |
21 | cr equ 0dh |
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22 | |||
23 | pos_read_tmp equ 0700h ;position for temporary read |
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24 | boot_program equ 07c00h ;position for boot code |
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25 | seg_read_kernel equ 01000h ;segment to kernel read |
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26 | |||
27 | jmp start_program |
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28 | nop |
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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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37 | |||
38 | xor ax, ax |
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39 | mov ss, ax |
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40 | mov sp, boot_program |
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41 | push ss |
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42 | pop ds |
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43 | |||
44 | ; print loading string |
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45 | mov si, loading+boot_program |
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46 | loop_loading: |
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47 | lodsb |
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48 | or al, al |
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49 | jz read_root_directory |
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50 | mov ah, 0eh |
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51 | mov bx, 7 |
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52 | int 10h |
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53 | jmp loop_loading |
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54 | |||
55 | read_root_directory: |
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56 | push ss |
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57 | pop es |
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58 | |||
59 | ; calculate some disk parameters |
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60 | ; - beginning sector of RootDir |
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61 | mov ax, word [BPB_FATSz16+boot_program] |
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62 | xor cx, cx |
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63 | mov cl, byte [BPB_NumFATs+boot_program] |
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64 | mul cx |
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65 | add ax, word [BPB_RsvdSecCnt+boot_program] |
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66 | mov word [FirstRootDirSecNum+boot_program], ax ; 19 |
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67 | mov si, ax |
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68 | |||
69 | ; - count of sectors in RootDir |
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70 | mov bx, word [BPB_BytsPerSec+boot_program] |
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71 | mov cl, 5 ; divide ax by 32 |
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72 | shr bx, cl ; bx = directory entries per sector |
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73 | mov ax, word [BPB_RootEntCnt+boot_program] |
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74 | xor dx, dx |
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75 | div bx |
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76 | mov word [RootDirSecs+boot_program], ax ; 14 |
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77 | |||
78 | ; - data start |
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79 | add si, ax ; add beginning sector of RootDir and count sectors in RootDir |
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80 | mov word [data_start+boot_program], si ; 33 |
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81 | ; reading root directory |
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82 | ; al=count root dir sectrors !!!! TODO: al, max 255 sectors !!!! |
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83 | mov ah, 2 ; read |
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84 | push ax |
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85 | |||
86 | mov ax, word [FirstRootDirSecNum+boot_program] |
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87 | call conv_abs_to_THS ; convert abs sector (AX) to BIOS T:H:S (track:head:sector) |
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88 | pop ax |
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89 | mov bx, pos_read_tmp ; es:bx read buffer |
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90 | call read_sector |
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91 | |||
92 | mov si, bx ; read buffer address: es:si |
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93 | mov ax, [RootDirSecs+boot_program] |
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94 | mul word [BPB_BytsPerSec+boot_program] |
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95 | add ax, si ; AX = end of root dir. in buffer pos_read_tmp |
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96 | |||
97 | ; find kernel file in root directory |
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98 | loop_find_dir_entry: |
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99 | push si |
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100 | mov cx, 11 |
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101 | mov di, kernel_name+boot_program |
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102 | rep cmpsb ; compare es:si and es:di, cx bytes long |
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103 | pop si |
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104 | je found_kernel_file |
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105 | add si, 32 ; next dir. entry |
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106 | cmp si, ax ; end of directory |
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107 | jb loop_find_dir_entry |
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108 | |||
109 | file_error_message: |
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110 | mov si, error_message+boot_program |
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111 | |||
112 | loop_error_message: |
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113 | lodsb |
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114 | or al, al |
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115 | jz freeze_pc |
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116 | mov ah, 0eh |
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117 | mov bx, 7 |
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118 | int 10h |
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119 | jmp loop_error_message |
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120 | |||
121 | freeze_pc: |
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122 | jmp $ ; endless loop |
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123 | |||
124 | ; === KERNEL FOUND. LOADING... === |
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125 | |||
126 | found_kernel_file: |
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127 | mov bp, [si+01ah] ; first cluster of kernel file |
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128 | ; |
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129 | mov [cluster1st+boot_program], bp ; starting cluster of kernel file |
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130 | ; <\diamond> |
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131 | |||
132 | ; reading first FAT table |
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133 | mov ax, word [BPB_RsvdSecCnt+boot_program] ; begin first FAT abs sector number |
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134 | call conv_abs_to_THS ; convert abs sector (AX) to BIOS T:H:S (track:head:sector) |
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135 | mov bx, pos_read_tmp ; es:bx read position |
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136 | mov ah, 2 ; ah=2 (read) |
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137 | mov al, byte [BPB_FATSz16+boot_program] ; FAT size in sectors (TODO: max 255 sectors) |
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138 | call read_sector |
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139 | jc file_error_message ; read error |
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140 | |||
141 | mov ax, seg_read_kernel |
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142 | mov es, ax |
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143 | xor bx, bx ; es:bx = 1000h:0000h |
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144 | |||
145 | |||
146 | ; reading kernel file |
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147 | loop_obtains_kernel_data: |
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148 | ; read one cluster of file |
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149 | call obtain_cluster |
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150 | jc file_error_message ; read error |
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151 | |||
152 | ; add one cluster length to segment:offset |
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153 | push bx |
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154 | mov bx, es |
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155 | mov ax, word [BPB_BytsPerSec+boot_program] ;\ |
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156 | movsx cx, byte [BPB_SecPerClus+boot_program] ; | !!! TODO: !!! |
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157 | mul cx ; | out this from loop !!! |
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158 | shr ax, 4 ;/ |
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159 | add bx, ax |
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160 | mov es, bx |
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161 | pop bx |
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162 | |||
163 | mov di, bp |
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164 | shr di, 1 |
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165 | pushf |
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166 | add di, bp ; di = bp * 1.5 |
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167 | add di, pos_read_tmp |
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168 | mov ax, [di] ; read next entry from FAT-chain |
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169 | popf |
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170 | jc move_4_right |
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171 | and ax, 0fffh |
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172 | jmp verify_end_sector |
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173 | move_4_right: |
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174 | mov cl, 4 |
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175 | shr ax, cl |
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176 | verify_end_sector: |
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177 | cmp ax, 0ff8h ; last cluster |
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178 | jae execute_kernel |
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179 | mov bp, ax |
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180 | jmp loop_obtains_kernel_data |
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181 | |||
182 | execute_kernel: |
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183 | ; |
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184 | mov ax, 'KL' |
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185 | push 0 |
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186 | pop ds |
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187 | mov si, loader_block+boot_program |
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188 | ; |
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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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192 | |||
193 | |||
194 | ;------------------------------------------ |
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195 | ; loading cluster from file to es:bx |
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196 | obtain_cluster: |
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197 | ; bp - cluster number to read |
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198 | ; carry = 0 -> read OK |
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199 | ; carry = 1 -> read ERROR |
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200 | |||
201 | ; print one dot |
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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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207 | |||
208 | writesec: |
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209 | ; convert cluster number to sector number |
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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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216 | |||
217 | call conv_abs_to_THS ; convert abs sector (AX) to BIOS T:H:S (track:head:sector) |
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218 | patchhere: |
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219 | mov ah, 2 ; ah=2 (read) |
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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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223 | ;------------------------------------------ |
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224 | |||
225 | ;------------------------------------------ |
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226 | ; read sector from disk |
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227 | read_sector: |
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228 | push bp |
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229 | mov bp, 20 ; try 20 times |
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230 | newread: |
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231 | dec bp |
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232 | jz file_error_message |
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233 | push ax bx cx dx |
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234 | int 13h |
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235 | pop dx cx bx ax |
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236 | jc newread |
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237 | pop bp |
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238 | retn |
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239 | ;------------------------------------------ |
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240 | ; convert abs. sector number (AX) to BIOS T:H:S |
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241 | ; sector number = (abs.sector%BPB_SecPerTrk)+1 |
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242 | ; pre.track number = (abs.sector/BPB_SecPerTrk) |
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243 | ; head number = pre.track number%BPB_NumHeads |
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244 | ; track number = pre.track number/BPB_NumHeads |
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245 | ; Return: cl - sector number |
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246 | ; ch - track number |
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247 | ; dl - drive number (0 = a:) |
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248 | ; dh - head number |
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249 | conv_abs_to_THS: |
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250 | push bx |
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251 | mov bx, word [BPB_SecPerTrk+boot_program] |
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252 | xor dx, dx |
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253 | div bx |
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254 | inc dx |
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255 | mov cl, dl ; cl = sector number |
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256 | mov bx, word [BPB_NumHeads+boot_program] |
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257 | xor dx, dx |
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258 | div bx |
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259 | ; !!!!!!! ax = track number, dx = head number |
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260 | mov ch, al ; ch=track number |
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261 | xchg dh, dl ; dh=head number |
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262 | mov dl, 0 ; dl=0 (drive 0 (a:)) |
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263 | pop bx |
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264 | retn |
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265 | ;------------------------------------------ |
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266 | |||
3500 | Serge | 267 | if lang eq sp |
268 | loading db cr,lf,'Iniciando el sistema ',00h |
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269 | else |
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2434 | Serge | 270 | loading db cr,lf,'Starting system ',00h |
3500 | Serge | 271 | end if |
2434 | Serge | 272 | error_message db 13,10 |
273 | kernel_name db 'KERNEL MNT ?',cr,lf,00h |
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274 | FirstRootDirSecNum dw ? |
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275 | RootDirSecs dw ? |
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276 | data_start dw ? |
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277 | |||
278 | ; |
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279 | write1st: |
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280 | push cs |
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281 | pop ds |
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282 | mov byte [patchhere+1+boot_program], 3 ; change ah=2 to ah=3 |
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283 | mov bp, [cluster1st+boot_program] |
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284 | push 1000h |
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285 | pop es |
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286 | xor bx, bx |
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287 | call writesec |
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288 | mov byte [patchhere+1+boot_program], 2 ; change back ah=3 to ah=2 |
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289 | retf |
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290 | cluster1st dw ? |
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291 | loader_block: |
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292 | db 1 |
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293 | dw 0 |
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294 | dw write1st+boot_program |
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295 | dw 0 |
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296 | ; <\diamond> |
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297 | |||
298 | times 0x1fe-$ db 00h |
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299 | |||
300 | db 55h,0aah ;boot signature\diamond>\diamond> |