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Rev | Author | Line No. | Line |
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2288 | clevermous | 1 | ; Copyright (c) 2008-2009, diamond |
2 | ; All rights reserved. |
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3 | ; |
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4 | ; Redistribution and use in source and binary forms, with or without |
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5 | ; modification, are permitted provided that the following conditions are met: |
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6 | ; * Redistributions of source code must retain the above copyright |
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7 | ; notice, this list of conditions and the following disclaimer. |
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8 | ; * Redistributions in binary form must reproduce the above copyright |
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9 | ; notice, this list of conditions and the following disclaimer in the |
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10 | ; documentation and/or other materials provided with the distribution. |
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11 | ; * Neither the name of the |
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12 | ; names of its contributors may be used to endorse or promote products |
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13 | ; derived from this software without specific prior written permission. |
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14 | ; |
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15 | ; THIS SOFTWARE IS PROVIDED BY Alexey Teplov aka |
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16 | ; EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
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17 | ; WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
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18 | ; DISCLAIMED. IN NO EVENT SHALL |
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19 | ; DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
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20 | ; (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
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21 | ; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
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22 | ; ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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23 | ; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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24 | ; SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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25 | ;***************************************************************************** |
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26 | |||
27 | org 0x7E00 |
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28 | ; the KordOS FAT32 bootsector loads first cluster of this file to 0:7E00 and transfers control to here |
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29 | ; ss:bp = 0:7C00 |
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30 | ; ds = 0 |
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31 | virtual at bp |
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32 | rb 3 ; BS_jmpBoot |
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33 | rb 8 ; BS_OEMName, ignored |
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34 | dw ? ; BPB_BytsPerSec |
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35 | BPB_SecsPerClus db ? |
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36 | BPB_RsvdSecCnt dw ? |
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37 | BPB_NumFATs db ? |
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38 | BPB_RootEntCnt dw ? |
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39 | dw ? ; BPB_TotSec16 |
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40 | db ? ; BPB_Media |
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41 | dw ? ; BPB_FATSz16 = 0 for FAT32 |
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42 | BPB_SecPerTrk dw ? |
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43 | BPB_NumHeads dw ? |
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44 | BPB_HiddSec dd ? |
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45 | dd ? ; BPB_TotSec32 |
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46 | BPB_FATSz32 dd ? |
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47 | BPB_ExtFlags dw ? |
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48 | dw ? ; BPB_FSVer |
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49 | BPB_RootClus dd ? |
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50 | filesize: |
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51 | dw ? ; BPB_FSInfo |
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52 | dw ? ; BPB_BkBootSec |
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53 | rb 12 ; BPB_Reserved |
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54 | BS_DrvNum db ? |
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55 | db ? ; BS_Reserved1 |
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56 | db ? ; BS_BootSig |
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57 | dd ? ; BS_VolID |
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58 | ; rb 11 ; BS_VolLab |
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59 | ; rb 5 ; BS_FilSysType, first 5 bytes |
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60 | read_sectors32 dw ? |
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61 | read_sectors2 dw ? |
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62 | err_ dw ? |
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63 | noloader dw ? |
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64 | cachelimit dw ? |
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65 | fatcachehead rw 2 |
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66 | fatcacheend dw ? |
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67 | rb 3 ; BS_FilSysType, last 3 bytes |
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68 | curseg dw ? |
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69 | num_sectors dd ? |
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70 | cur_cluster dd ? |
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71 | next_cluster dd ? |
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72 | flags dw ? |
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73 | cur_delta dd ? |
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74 | end virtual |
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75 | |||
76 | ; procedures from boot sector |
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77 | ; LBA version |
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78 | lba_read_sectors2 = 7CD6h |
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79 | lba_err = 7CAAh |
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80 | lba_noloader = 7CA7h ; = lba_err - 3 |
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81 | ; CHS version |
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82 | chs_read_sectors2 = 7CD2h |
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83 | chs_err = 7CA6h |
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84 | chs_noloader = 7CA3h ; = chs_err - 3 |
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85 | |||
86 | push eax cx ; save our position on disk |
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87 | ; determine version of bootsector (LBA vs CHS) |
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88 | mov [read_sectors2], chs_read_sectors2 |
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89 | mov bx, chs_err |
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90 | mov [err_], bx |
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91 | ; mov [noloader], chs_noloader |
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92 | cmp byte [bx], 0xE8 ; [chs_err] = 0xE8 for CHS version, 0x14 for LBA version |
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93 | jz @f |
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94 | add [read_sectors2], lba_read_sectors2 - chs_read_sectors2 |
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95 | add [err_], lba_err - chs_err |
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96 | ; mov [noloader], lba_noloader |
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97 | @@: |
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98 | xor bx, bx |
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99 | ; determine size of cache for folders |
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100 | int 12h ; ax = size of available base memory in Kb |
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101 | sub ax, 92000h / 1024 |
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102 | jae @f |
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103 | nomem: |
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104 | mov si, nomem_str |
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105 | jmp [err_] |
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106 | @@: |
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107 | shr ax, 3 |
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108 | mov [cachelimit], ax ; size of cache - 1 |
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109 | mov es, bx |
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110 | ; no folders in cache yet |
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111 | mov di, foldcache_clus |
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112 | mov cx, 8*4/2 + 1 |
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113 | xor ax, ax |
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114 | rep stosw |
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115 | ; bootsector code caches one FAT sector, [bp-14], in 6000:0000 |
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116 | ; initialize our (more advanced) FAT caching from this |
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117 | mov di, 8400h |
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118 | mov cx, di |
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119 | lea si, [fatcachehead] |
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120 | mov [si], si ; no sectors in cache: |
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121 | mov [si+2], si ; 'prev' & 'next' links point to self |
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122 | mov [fatcacheend], di ; first free item = 8400h |
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123 | stosw ; 'next cached sector' link |
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124 | stosw ; 'prev cached sector' link |
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125 | mov eax, [bp-14] |
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126 | stosd ; first sector number in cache |
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127 | test eax, eax |
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128 | js @f |
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129 | mov [si], cx ; 'first cached sector' link = 8400h |
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130 | mov [si+2], cx ; 'next cached sector' link = 8400h |
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131 | mov [fatcacheend], di ; first free item = 8406h |
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132 | @@: |
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133 | ; if cluster = sector, we need to read second part of our file |
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134 | ; (bootsector loads only first cluster of kordldr.f32) |
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135 | pop cx eax ; restore our position on disk |
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136 | cmp cx, 1 |
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137 | ja kordldr_full |
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138 | sub eax, [bp-10] |
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139 | inc eax |
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140 | inc eax ; eax = first cluster of kordldr.f32 |
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141 | call get_next_cluster |
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142 | jc @f |
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143 | ; jmp [noloader] |
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144 | mov ax, [err_] |
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145 | sub ax, 3 |
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146 | jmp ax |
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147 | @@: |
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148 | dec eax |
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149 | dec eax |
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150 | push 0x800 |
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151 | pop es |
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152 | call [read_sectors2] |
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153 | kordldr_full: |
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154 | ; bootsector code has read some data of root directory to 8000:0000 |
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155 | ; initialize our folder caching from this |
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156 | mov eax, [BPB_RootClus] |
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157 | mov [foldcache_clus], eax |
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158 | mov cx, [curseg] |
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159 | mov ax, 8000h |
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160 | sub cx, ax ; cx = size of data read in paragraphs (0x10 bytes) |
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161 | shr cx, 1 ; cx = size of folder data read in entries (0x20 bytes) |
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162 | mov [foldcache_size], cx |
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163 | shl cx, 4 |
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164 | push ds |
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165 | mov ds, ax |
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166 | push 0x9000 |
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167 | pop es |
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168 | xor si, si |
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169 | xor di, di |
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170 | rep movsw |
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171 | pop ds |
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172 | ; ...continue loading... |
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173 | mov di, secondary_loader_info |
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174 | call load_file |
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175 | test bx, bx |
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176 | mov bx, [err_] |
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177 | jz @f |
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178 | mov si, aKernelNotFound |
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179 | jmp bx |
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180 | @@: |
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181 | ; for subsequent calls to callback function, hook error handler |
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182 | ; push hooked_err / ret |
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183 | mov dword [bx], 0x68 + (hooked_err shl 8) + (0xC3 shl 24) |
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184 | ; set registers for secondary loader |
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185 | mov ah, [bp-2] ; drive id |
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186 | mov al, 'f' |
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187 | btr ax, 15 |
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188 | jnc @f |
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189 | mov al, 'h' |
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190 | @@: |
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191 | mov bx, '32' |
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192 | mov si, callback |
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193 | jmp far [si+secondary_loader_info-callback] |
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194 | |||
195 | nomem_str db 'No memory',0 |
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196 | |||
197 | cluster2sector: |
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198 | sub eax, 2 |
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199 | clustersz2sectorsz: |
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200 | movzx ecx, [BPB_SecsPerClus] |
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201 | mul ecx |
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202 | ret |
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203 | |||
204 | get_next_cluster: |
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205 | ; in: eax = cluster |
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206 | ; out: if there is next cluster: CF=1, eax = next cluster |
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207 | ; out: if there is no next cluster: CF=0 |
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208 | push di bx |
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209 | push ds |
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210 | push ss |
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211 | pop ds |
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212 | push ax |
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213 | shr eax, 7 |
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214 | ; eax = FAT sector number; look in cache |
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215 | mov di, 8400h |
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216 | .cache_lookup: |
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217 | cmp di, [fatcacheend] |
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218 | jae .not_in_cache |
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219 | scasd |
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220 | scasd |
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221 | jnz .cache_lookup |
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222 | .in_cache: |
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223 | sub di, 8 |
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224 | ; delete this sector from the list |
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225 | push si |
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226 | mov si, [di] |
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227 | mov bx, [di+2] |
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228 | mov [si+2], bx |
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229 | mov [bx], si |
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230 | pop si |
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231 | jmp @f |
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232 | .not_in_cache: |
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233 | ; cache miss |
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234 | ; cache is full? |
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235 | mov di, [fatcacheend] |
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236 | cmp di, 8C00h |
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237 | jnz .cache_not_full |
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238 | ; yes, delete the oldest entry |
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239 | mov di, [fatcachehead] |
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240 | mov bx, [di] |
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241 | mov [fatcachehead], bx |
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242 | push word [di+2] |
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243 | pop word [bx+2] |
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244 | jmp .cache_append |
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245 | .cache_not_full: |
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246 | ; no, allocate new sector |
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247 | add [fatcacheend], 8 |
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248 | .cache_append: |
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249 | ; read FAT |
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250 | mov [di+4], eax |
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251 | push es |
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252 | pushad |
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253 | lea cx, [di + 0x10000 - 0x8400 + (0x6000 shr (9-3))] ; +0x10000 - for FASM |
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254 | shl cx, 9-3 |
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255 | mov es, cx |
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256 | xor bx, bx |
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257 | mov cx, 1 |
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258 | add eax, [bp-6] ; FAT start |
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259 | sub eax, [bp-10] |
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260 | call [read_sectors2] |
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261 | popad |
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262 | pop es |
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263 | @@: |
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264 | ; add new sector to the end of list |
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265 | mov bx, di |
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266 | xchg bx, [fatcachehead+2] |
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267 | push word [bx] |
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268 | pop word [di] |
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269 | mov [bx], di |
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270 | mov [di+2], bx |
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271 | ; get requested item |
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272 | lea ax, [di + 0x10000 - 0x8400 + (0x6000 shr (9-3))] |
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273 | pop di |
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274 | and di, 0x7F |
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275 | shl di, 2 |
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276 | shl ax, 9-3 |
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277 | mov ds, ax |
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278 | and byte [di+3], 0x0F |
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279 | mov eax, [di] |
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280 | pop ds |
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281 | pop bx di |
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282 | ;and eax, 0x0FFFFFFF |
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283 | cmp eax, 0x0FFFFFF7 |
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284 | ret |
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285 | |||
286 | if $ > 0x8000 |
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287 | error 'get_next_cluster must fit in first sector of kordldr.f32!' |
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288 | end if |
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289 | |||
290 | load_file: |
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291 | ; in: ss:bp = 0:7C00 |
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292 | ; in: ds:di -> information structure |
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293 | ; dw:dw address |
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294 | ; dw limit in 4Kb blocks (0x1000 bytes) (must be non-zero and not greater than 0x100) |
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295 | ; ASCIIZ name |
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296 | ; out: bx = status: bx=0 - ok, bx=1 - file is too big, only part of file was loaded, bx=2 - file not found |
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297 | ; out: dx:ax = file size (0xFFFFFFFF if file not found) |
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298 | mov eax, [BPB_RootClus] ; start from root directory |
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299 | or dword [filesize], -1 ; initialize file size with invalid value |
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300 | lea si, [di+6] |
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301 | parse_dir_loop: |
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302 | ; convert name to FAT name |
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303 | push di |
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304 | push ax |
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305 | push ss |
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306 | pop es |
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307 | ; convert ASCIIZ filename to FAT name |
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308 | filename equ bp |
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309 | mov di, filename |
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310 | push di |
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311 | mov cx, 8+3 |
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312 | mov al, ' ' |
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313 | rep stosb |
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314 | pop di |
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315 | mov cl, 8 ; 8 symbols per name |
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316 | mov bl, 1 |
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317 | nameloop: |
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318 | lodsb |
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319 | test al, al |
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320 | jz namedone |
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321 | cmp al, '/' |
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322 | jz namedone |
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323 | cmp al, '.' |
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324 | jz namedot |
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325 | dec cx |
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326 | js badname |
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327 | cmp al, 'a' |
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328 | jb @f |
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329 | cmp al, 'z' |
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330 | ja @f |
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331 | sub al, 'a'-'A' |
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332 | @@: |
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333 | stosb |
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334 | jmp nameloop |
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335 | namedot: |
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336 | inc bx |
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337 | jp badname |
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338 | add di, cx |
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339 | mov cl, 3 |
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340 | jmp nameloop |
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341 | badname: ; do not make direct js/jp to notfound_pop: |
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342 | ; this generates long forms of conditional jumps and results in longer code |
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343 | jmp notfound_pop |
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344 | namedone: |
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345 | ; scan directory |
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346 | pop ax ; eax = cluster of directory |
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347 | ; high word of eax is preserved by operations above |
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348 | push ds |
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349 | push si |
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350 | ; read a folder sector-by-sector and scan |
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351 | ; first, try to use the cache |
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352 | push ss |
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353 | pop ds |
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354 | mov di, foldcache_mark |
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355 | xor bx, bx |
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356 | mov cx, [cachelimit] |
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357 | @@: |
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358 | lea si, [di+bx] |
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359 | mov edx, dword [foldcache_clus+si-foldcache_mark+bx] |
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360 | cmp edx, eax |
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361 | jz cacheok |
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362 | test edx, edx |
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363 | jz cacheadd ; the cache has place for new entry |
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364 | inc bx |
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365 | inc bx |
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366 | dec cx |
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367 | jns @b |
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368 | ; the folder is not present in the cache, so add it |
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369 | ; the cache is full; find the oldest entry and replace it with the new one |
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370 | mov bx, -2 |
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371 | mov dx, [cachelimit] |
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372 | @@: |
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373 | inc bx |
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374 | inc bx |
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375 | cmp word [di+bx], dx ; marks have values 0 through [cachelimit] |
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376 | jnz @b |
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377 | lea si, [di+bx] |
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378 | cacheadd: |
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379 | or word [di+bx], 0xFFFF ; very big value, it will be changed soon |
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380 | and [foldcache_size+di-foldcache_mark+bx], 0 ; no folder items yet |
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381 | mov dword [foldcache_clus+si-foldcache_mark+bx], eax |
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382 | cacheok: |
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383 | ; update cache marks |
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384 | mov dx, [di+bx] |
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385 | mov cx, [foldcache_size+di-foldcache_mark+bx] |
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386 | mov di, [cachelimit] |
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387 | add di, di |
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388 | cacheupdate: |
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389 | cmp [foldcache_mark+di], dx |
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390 | adc [foldcache_mark+di], 0 |
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391 | dec di |
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392 | dec di |
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393 | jns cacheupdate |
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394 | and [foldcache_mark+bx], 0 |
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395 | ; done, bx contains (position in cache)*2 |
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396 | ;mov dx, bx |
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397 | ;shl dx, 8 ; dx = (position in cache)*0x2000/0x10 |
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398 | ;add dx, 0x9000 |
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399 | lea dx, [bx + 0x90] |
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400 | xchg dl, dh |
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401 | mov ds, dx |
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402 | mov si, filename ; ss:si -> filename in FAT style |
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403 | call scan_for_filename |
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404 | jz lookup_done |
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405 | ; cache miss, read folder data from disk |
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406 | mov bx, cx |
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407 | shr bx, 4 |
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408 | shl cx, 5 |
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409 | mov di, cx ; es:di -> free space in cache entry |
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410 | ; external loop: scan clusters |
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411 | folder_next_cluster: |
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412 | ; internal loop: scan sectors in cluster |
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413 | push eax |
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414 | call cluster2sector |
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415 | folder_next_sector: |
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416 | ; skip first bx sectors |
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417 | dec bx |
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418 | jns folder_skip_sector |
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419 | push cx |
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420 | push es di |
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421 | push 0x8000 |
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422 | pop es |
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423 | xor bx, bx |
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424 | mov cx, 1 |
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425 | push es |
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426 | push eax |
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427 | call [read_sectors2] |
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428 | pop eax |
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429 | ; copy data to the cache... |
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430 | pop ds |
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431 | pop di es |
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432 | cmp di, 0x2000 ; ...if there is free space, of course |
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433 | jae @f |
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434 | pusha |
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435 | mov cx, 0x100 |
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436 | xor si, si |
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437 | rep movsw |
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438 | mov di, es |
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439 | shr di, 8 |
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440 | add [ss:foldcache_size+di-0x90], 0x10 ; 0x10 new entries in the cache |
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441 | popa |
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442 | @@: |
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443 | push es |
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444 | mov cl, 0x10 ; ch=0 at this point |
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445 | call scan_for_filename |
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446 | pop es |
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447 | pop cx |
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448 | jz lookup_done_pop |
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449 | folder_skip_sector: |
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450 | inc eax |
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451 | loop folder_next_sector |
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452 | pop eax ; eax = current cluster |
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453 | call get_next_cluster |
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454 | jc folder_next_cluster |
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455 | stc |
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456 | push eax |
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457 | lookup_done_pop: |
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458 | pop eax |
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459 | lookup_done: |
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460 | pop si |
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461 | ; CF=1 <=> failed |
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462 | jnc found |
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463 | pop ds |
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464 | notfound: |
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465 | pop di |
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466 | notfound2: |
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467 | mov bx, 2 ; file not found |
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468 | mov ax, 0xFFFF |
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469 | mov dx, ax ; invalid file size |
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470 | ret |
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471 | notfound_pop: |
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472 | pop ax |
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473 | jmp notfound |
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474 | found: |
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475 | mov eax, [di+20-2] |
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476 | mov edx, [di+28] |
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477 | mov ax, [di+26] ; get cluster |
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478 | test byte [di+11], 10h ; directory? |
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479 | pop ds |
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480 | pop di |
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481 | jz regular_file |
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482 | cmp byte [si-1], 0 |
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483 | jz notfound2 ; don't read directories as regular files |
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484 | ; ok, we have found a directory and the caller requested a file into it |
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485 | jmp parse_dir_loop ; restart with new cluster in ax |
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486 | regular_file: |
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487 | cmp byte [si-1], 0 |
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488 | jnz notfound2 ; file does not contain another files |
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489 | ; ok, we have found a regular file and the caller requested it |
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490 | ; save file size |
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491 | mov [filesize], edx |
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492 | mov si, [di+4] ; [ds:di+4] = limit in 4K blocks |
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493 | shl si, 3 |
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494 | push si |
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495 | les bx, [di] ; es:bx -> buffer |
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496 | clusloop: |
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497 | ; eax = first cluster, top of stack contains limit in sectors |
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498 | mov esi, eax ; remember current cluster |
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499 | xor ecx, ecx ; ecx will contain number of consecutive clusters |
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500 | mov [cur_delta], ecx |
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501 | mov edi, eax |
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502 | clusfind: |
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503 | inc edi |
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504 | inc ecx |
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505 | call get_next_cluster |
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506 | jnc clusread |
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507 | cmp eax, edi |
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508 | jz clusfind |
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509 | stc |
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510 | clusread: |
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511 | pop di ; limit in sectors |
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512 | movzx edi, di |
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513 | push eax ; save next cluster |
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514 | pushf ; save flags |
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515 | ; read cx clusters, starting from si |
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516 | ; calculate number of sectors |
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517 | xchg eax, ecx |
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518 | call clustersz2sectorsz |
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519 | mov [num_sectors], eax |
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520 | jmp @f |
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521 | continue_load_file: |
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522 | les bx, [di] ; es:bx -> buffer |
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523 | movzx edi, word [di+4] ; di = limit in 4K blocks |
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524 | shl di, 3 ; now di = limit in sectors |
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525 | mov eax, [num_sectors] |
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526 | mov esi, [cur_cluster] |
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527 | push [next_cluster] |
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528 | push [flags] |
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529 | test eax, eax |
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530 | jz nextclus |
||
531 | @@: |
||
532 | ; eax = number of sectors; compare with limit |
||
533 | cmp eax, edi |
||
534 | seta dl |
||
535 | push dx ; limit was exceeded? |
||
536 | jbe @f |
||
537 | mov eax, edi |
||
538 | @@: |
||
539 | sub di, ax ; calculate new limit |
||
540 | sub [num_sectors], eax |
||
541 | mov [cur_cluster], esi |
||
542 | ; calculate starting sector |
||
543 | push ax |
||
544 | xchg eax, esi |
||
545 | call cluster2sector |
||
546 | pop cx |
||
547 | add eax, [cur_delta] |
||
548 | add [cur_delta], ecx |
||
549 | ; read |
||
550 | call [read_sectors2] |
||
551 | pop dx |
||
552 | ; next cluster? |
||
553 | nextclus: |
||
554 | popf |
||
555 | pop eax |
||
556 | mov [next_cluster], eax |
||
557 | pushf |
||
558 | pop [flags] |
||
559 | jnc @f ; no next cluster => return |
||
560 | mov dl, 1 ; dh=0 in any case |
||
561 | test di, di |
||
562 | jz @f ; if there is next cluster but current limit is 0 => return: limit exceeded |
||
563 | push di |
||
564 | jmp clusloop ; all is ok, continue |
||
565 | hooked_err: |
||
566 | mov sp, 7C00h-14-2 ; restore stack |
||
567 | mov dx, 3 ; return: read error |
||
568 | @@: |
||
569 | mov bx, dx |
||
570 | mov ax, [filesize] |
||
571 | mov dx, [filesize+2] |
||
572 | ret |
||
573 | |||
574 | scan_for_filename: |
||
575 | ; in: ss:si -> 11-bytes FAT name |
||
576 | ; in: ds:0 -> part of directory data |
||
577 | ; in: cx = number of entries |
||
578 | ; in: bh = 0 |
||
579 | ; out: if found: CF=0, ZF=1, es:di -> directory entry |
||
580 | ; out: if not found, but continue required: CF=1 and ZF=0 |
||
581 | ; out: if not found and zero item reached: CF=1 and ZF=1 |
||
582 | push ds |
||
583 | pop es |
||
584 | xor di, di |
||
585 | push cx |
||
586 | jcxz snoent |
||
587 | sloop: |
||
588 | cmp byte [di], bh |
||
589 | jz snotfound |
||
590 | test byte [di+11], 8 ; volume label? |
||
591 | jnz scont ; ignore volume labels |
||
592 | pusha |
||
593 | mov cx, 11 |
||
594 | repz cmps byte [ss:si], byte [es:di] |
||
595 | popa |
||
596 | jz sdone |
||
597 | scont: |
||
598 | add di, 0x20 |
||
599 | loop sloop |
||
600 | snoent: |
||
601 | inc cx ; clear ZF flag |
||
602 | snotfound: |
||
603 | stc |
||
604 | sdone: |
||
605 | pop cx |
||
606 | lrdret: |
||
607 | ret |
||
608 | |||
609 | ; Callback function for secondary loader |
||
610 | callback: |
||
611 | ; in: ax = function number; only functions 1 and 2 are defined for now |
||
612 | ; save caller's stack |
||
613 | mov dx, ss |
||
614 | mov cx, sp |
||
615 | ; set our stack (required because we need ss=0) |
||
616 | xor si, si |
||
617 | mov ss, si |
||
618 | mov sp, 7C00h-10 |
||
619 | mov bp, 7C00h |
||
620 | push dx |
||
621 | push cx |
||
622 | ; call our function |
||
623 | stc ; unsupported function |
||
624 | dec ax |
||
625 | jz callback_readfile |
||
626 | dec ax |
||
627 | jnz callback_ret |
||
628 | ; function 2: continue loading file |
||
629 | ; can be called only after function 1 returned value bx=1 (only part of file was loaded) |
||
630 | ; in: ds:di -> information structure |
||
631 | ; dw:dw address |
||
632 | ; dw limit in 4Kb blocks (0x1000 bytes) (must be non-zero and not greater than 0x100) |
||
633 | ; out: bx=0 - ok, bx=1 - still only part of file was loaded, bx=3 - read error |
||
634 | ; out: dx:ax = file size |
||
635 | call continue_load_file |
||
636 | jmp callback_ret_succ |
||
637 | callback_readfile: |
||
638 | ; function 1: read file |
||
639 | ; in: ds:di -> information structure |
||
640 | ; dw:dw address |
||
641 | ; dw limit in 4Kb blocks (0x1000 bytes) (must be non-zero and not greater than 0x100) |
||
642 | ; ASCIIZ name |
||
643 | ; out: bx=0 - ok, bx=1 - file is too big, only part of file was loaded, bx=2 - file not found, bx=3 - read error |
||
644 | ; out: dx:ax = file size (0xFFFFFFFF if file was not found) |
||
645 | call load_file |
||
646 | callback_ret_succ: |
||
647 | clc ; function is supported |
||
648 | callback_ret: |
||
649 | ; restore caller's stack |
||
650 | pop cx |
||
651 | pop ss |
||
652 | mov sp, cx |
||
653 | ; return to caller |
||
654 | retf |
||
655 | |||
656 | secondary_loader_info: |
||
657 | dw 0, 0x1000 |
||
658 | dw 0x30000 / 0x1000 |
||
659 | db 'kord/loader',0 |
||
660 | aKernelNotFound db 'Fatal error: cannot load the secondary loader',0 |
||
661 | |||
662 | ;if $ > 0x8200 |
||
663 | ;error 'total size of kordldr.f32 must not exceed 1024 bytes!' |
||
664 | ;end if |
||
665 | |||
666 | ;foldcache_clus dd 0,0,0,0,0,0,0,0 ; start with no folders in cache |
||
667 | ;foldcache_mark dw 0 |
||
668 | ; rw 7 |
||
669 | ;foldcache_size rw 8 |
||
670 | foldcache_clus rd 8 |
||
671 | foldcache_mark rw 8 |
||
672 | foldcache_size rw 8=> |