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1065 | Lrz | 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 | |||
1132 | Lrz | 27 | jmp far 0:real_start |
1065 | Lrz | 28 | ; special text |
29 | org $+0x7C00 |
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30 | real_start: |
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31 | ; initialize |
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1132 | Lrz | 32 | xor ax, ax |
33 | mov ss, ax |
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34 | mov sp, 0x7C00 |
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35 | mov ds, ax |
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36 | mov es, ax |
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37 | cld |
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38 | sti |
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39 | mov [bootdrive], dl |
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1065 | Lrz | 40 | ; check LBA support |
1132 | Lrz | 41 | mov ah, 41h |
42 | mov bx, 55AAh |
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43 | int 13h |
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44 | mov si, aNoLBA |
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45 | jc err_ |
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46 | cmp bx, 0AA55h |
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47 | jnz err_ |
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48 | test cl, 1 |
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49 | jz err_ |
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1065 | Lrz | 50 | ; get file system information |
51 | ; scan for Primary Volume Descriptor |
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1132 | Lrz | 52 | db 66h |
53 | push 10h-1 |
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54 | pop eax |
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1065 | Lrz | 55 | pvd_scan_loop: |
1132 | Lrz | 56 | mov cx, 1 |
57 | inc eax |
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58 | mov bx, 0x1000 |
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59 | call read_sectors |
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60 | jnc @f |
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1065 | Lrz | 61 | fatal_read_err: |
1132 | Lrz | 62 | mov si, aReadError |
63 | err_: |
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64 | call out_string |
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65 | mov si, aPressAnyKey |
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66 | call out_string |
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67 | xor ax, ax |
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68 | int 16h |
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69 | int 18h |
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70 | jmp $ |
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1065 | Lrz | 71 | @@: |
1132 | Lrz | 72 | push ds |
73 | pop es |
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74 | cmp word [bx+1], 'CD' |
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75 | jnz pvd_scan_loop |
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76 | cmp word [bx+3], '00' |
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77 | jnz pvd_scan_loop |
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78 | cmp byte [bx+5], '1' |
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79 | jnz pvd_scan_loop |
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1065 | Lrz | 80 | ; we have found ISO9660 descriptor, look for type |
1132 | Lrz | 81 | cmp byte [bx], 1 ; Primary Volume Descriptor? |
82 | jz pvd_found |
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83 | cmp byte [bx], 0xFF ; Volume Descriptor Set Terminator? |
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84 | jnz pvd_scan_loop |
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1065 | Lrz | 85 | ; Volume Descriptor Set Terminator reached, no PVD found - fatal error |
1132 | Lrz | 86 | mov si, no_pvd |
87 | jmp err_ |
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1065 | Lrz | 88 | pvd_found: |
1132 | Lrz | 89 | add bx, 80h |
90 | mov ax, [bx] |
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91 | mov [lb_size], ax |
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1065 | Lrz | 92 | ; calculate number of logical blocks in one sector |
1132 | Lrz | 93 | mov ax, 800h |
94 | cwd |
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95 | div word [bx] |
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96 | mov [lb_per_sec], ax |
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1065 | Lrz | 97 | ; get location of root directory |
1132 | Lrz | 98 | mov di, root_location |
99 | movzx eax, byte [bx+1Dh] |
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100 | add eax, [bx+1Eh] |
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101 | stosd |
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1065 | Lrz | 102 | ; get memory size |
1132 | Lrz | 103 | int 12h |
104 | mov si, nomem_str |
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105 | cmp ax, 71000h / 400h |
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106 | jb err_ |
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107 | shr ax, 1 |
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108 | sub ax, 60000h / 800h |
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109 | mov [size_rest], ax |
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110 | mov [free_ptr], 60000h / 800h |
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1065 | Lrz | 111 | ; load path table |
112 | ; if size > 62K => it's very strange, avoid using it |
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113 | ; if size > (size of cache)/2 => avoid using it too |
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1132 | Lrz | 114 | mov ecx, [bx+4] |
115 | cmp ecx, 0x10000 - 0x800 |
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116 | ja nopathtable |
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117 | shr ax, 1 |
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118 | cmp ax, 0x20 |
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119 | jae @f |
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120 | shl ax, 11 |
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121 | cmp cx, ax |
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122 | ja nopathtable |
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1065 | Lrz | 123 | @@: |
124 | ; size is ok, try to load it |
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1132 | Lrz | 125 | mov [pathtable_size], cx |
126 | mov eax, [bx+12] |
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127 | xor edx, edx |
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128 | div dword [lb_per_sec] |
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129 | imul dx, [bx] |
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130 | mov [pathtable_start], dx |
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131 | add cx, dx |
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132 | call cx_to_sectors |
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133 | xor bx, bx |
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134 | push 6000h |
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135 | pop es |
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136 | call read_sectors |
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137 | jc nopathtable |
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1065 | Lrz | 138 | ; path table has been loaded |
1132 | Lrz | 139 | inc [use_path_table] |
140 | sub [size_rest], cx |
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141 | add [free_ptr], cx |
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1065 | Lrz | 142 | nopathtable: |
143 | ; init cache |
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1132 | Lrz | 144 | mov ax, [size_rest] |
145 | mov [cache_size], ax |
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146 | mov ax, [free_ptr] |
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147 | mov [cache_start], ax |
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1065 | Lrz | 148 | ; load secondary loader |
1132 | Lrz | 149 | mov di, secondary_loader_info |
150 | call load_file |
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151 | test bx, bx |
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152 | jnz noloader |
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1065 | Lrz | 153 | ; set registers for secondary loader |
1132 | Lrz | 154 | mov ah, [bootdrive] |
155 | mov al, 'c' |
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156 | mov bx, 'is' |
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157 | mov si, callback |
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158 | jmp far [si-callback+secondary_loader_info] ; jump to 1000:0000 |
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1065 | Lrz | 159 | |
160 | noloader: |
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1132 | Lrz | 161 | mov si, aKernelNotFound |
162 | jmp err_ |
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1065 | Lrz | 163 | |
164 | read_sectors: |
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165 | ; es:bx = pointer to data |
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166 | ; eax = first sector |
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167 | ; cx = number of sectors |
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1132 | Lrz | 168 | pushad |
169 | push ds |
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1065 | Lrz | 170 | do_read_sectors: |
1132 | Lrz | 171 | push ax |
172 | push cx |
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173 | cmp cx, 0x7F |
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174 | jbe @f |
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175 | mov cx, 0x7F |
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1065 | Lrz | 176 | @@: |
177 | ; create disk address packet on the stack |
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178 | ; dq starting LBA |
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1132 | Lrz | 179 | db 66h |
180 | push 0 |
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181 | push eax |
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1065 | Lrz | 182 | ; dd buffer |
1132 | Lrz | 183 | push es |
184 | push bx |
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1065 | Lrz | 185 | ; dw number of blocks to transfer (no more than 0x7F) |
1132 | Lrz | 186 | push cx |
1065 | Lrz | 187 | ; dw packet size in bytes |
1132 | Lrz | 188 | push 10h |
1065 | Lrz | 189 | ; issue BIOS call |
1132 | Lrz | 190 | push ss |
191 | pop ds |
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192 | mov si, sp |
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193 | mov dl, [cs:bootdrive] |
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194 | mov ah, 42h |
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195 | int 13h |
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196 | jc diskreaderr |
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1065 | Lrz | 197 | ; restore stack |
1132 | Lrz | 198 | add sp, 10h |
1065 | Lrz | 199 | ; increase current sector & buffer; decrease number of sectors |
1132 | Lrz | 200 | movzx esi, cx |
201 | mov ax, es |
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202 | shl cx, 7 |
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203 | add ax, cx |
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204 | mov es, ax |
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205 | pop cx |
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206 | pop ax |
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207 | add eax, esi |
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208 | sub cx, si |
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209 | jnz do_read_sectors |
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210 | pop ds |
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211 | popad |
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212 | ret |
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1065 | Lrz | 213 | diskreaderr: |
1132 | Lrz | 214 | add sp, 10h + 2*2 |
215 | pop ds |
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216 | popad |
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217 | stc |
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1065 | Lrz | 218 | out_string.ret: |
1132 | Lrz | 219 | ret |
1065 | Lrz | 220 | |
221 | out_string: |
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222 | ; in: ds:si -> ASCIIZ string |
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1132 | Lrz | 223 | lodsb |
224 | test al, al |
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225 | jz .ret |
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226 | mov ah, 0Eh |
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227 | mov bx, 7 |
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228 | int 10h |
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229 | jmp out_string |
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1065 | Lrz | 230 | |
1132 | Lrz | 231 | aNoLBA db 'The drive does not support LBA!',0 |
232 | aReadError db 'Read error',0 |
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233 | no_pvd db 'Primary Volume Descriptor not found!',0 |
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234 | nomem_str db 'No memory',0 |
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235 | aPressAnyKey db 13,10,'Press any key...',13,10,0 |
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1065 | Lrz | 236 | |
237 | load_file: |
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238 | ; in: ds:di -> information structure |
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1132 | Lrz | 239 | ; dw:dw address |
240 | ; dw limit in 4Kb blocks (0x1000 bytes) (must be non-zero and not greater than 0x100) |
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241 | ; ASCIIZ name |
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1065 | Lrz | 242 | ; out: bx = status: bx=0 - ok, bx=1 - file is too big, only part of file was loaded, bx=2 - file not found |
243 | ; out: dx:ax = file size (0xFFFFFFFF if file not found) |
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244 | ; parse path to the file |
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1132 | Lrz | 245 | lea si, [di+6] |
246 | mov eax, [cs:root_location] |
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247 | cmp [cs:use_path_table], 0 |
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248 | jz parse_dir |
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1065 | Lrz | 249 | ; scan for path in path table |
1132 | Lrz | 250 | push di |
251 | push 6000h |
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252 | pop es |
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253 | mov di, [cs:pathtable_start] ; es:di = pointer to current entry in path table |
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254 | mov dx, 1 ; dx = number of current entry in path table, start from 1 |
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255 | mov cx, [cs:pathtable_size] |
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1065 | Lrz | 256 | pathtable_newparent: |
1132 | Lrz | 257 | mov bx, dx ; bx = number of current parent in path table: root = 1 |
1065 | Lrz | 258 | scan_path_table_e: |
1132 | Lrz | 259 | call is_last_component |
260 | jnc path_table_scanned |
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1065 | Lrz | 261 | scan_path_table_i: |
1132 | Lrz | 262 | cmp word [es:di+6], bx |
263 | jb .next |
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264 | ja path_table_notfound |
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265 | call test_filename1 |
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266 | jc .next |
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1065 | Lrz | 267 | @@: |
1132 | Lrz | 268 | lodsb |
269 | cmp al, '/' |
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270 | jnz @b |
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271 | jmp pathtable_newparent |
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1065 | Lrz | 272 | .next: |
273 | ; go to next entry |
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1132 | Lrz | 274 | inc dx |
275 | movzx ax, byte [es:di] |
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276 | add ax, 8+1 |
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277 | and al, not 1 |
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278 | add di, ax |
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279 | sub cx, ax |
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280 | ja scan_path_table_i |
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1065 | Lrz | 281 | path_table_notfound: |
1132 | Lrz | 282 | pop di |
283 | mov ax, -1 |
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284 | mov dx, ax |
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285 | mov bx, 2 ; file not found |
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286 | ret |
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1065 | Lrz | 287 | path_table_scanned: |
1132 | Lrz | 288 | movzx eax, byte [es:di+1] |
289 | add eax, [es:di+2] |
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290 | pop di |
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1065 | Lrz | 291 | parse_dir: |
292 | ; eax = logical block, ds:di -> information structure, ds:si -> file name |
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293 | ; was the folder already read? |
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1132 | Lrz | 294 | push di ds |
295 | push cs |
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296 | pop ds |
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297 | mov [cur_desc_end], 2000h |
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298 | mov bx, cachelist |
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1065 | Lrz | 299 | .scan1: |
1132 | Lrz | 300 | mov bx, [bx+2] |
301 | cmp bx, cachelist |
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302 | jz .notfound |
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303 | cmp [bx+4], eax |
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304 | jnz .scan1 |
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1065 | Lrz | 305 | .found: |
306 | ; yes; delete this item from the list (the following code will append this item to the tail) |
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1132 | Lrz | 307 | mov di, [bx] |
308 | push word [bx+2] |
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309 | pop word [di+2] |
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310 | mov di, [bx+2] |
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311 | push word [bx] |
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312 | pop word [di] |
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313 | mov di, bx |
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314 | jmp .scan |
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1065 | Lrz | 315 | .notfound: |
316 | ; no; load first sector of the folder to get its size |
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1132 | Lrz | 317 | push eax |
318 | push si |
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319 | mov si, 1 |
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320 | call load_phys_sector_for_lb_force |
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321 | mov bx, si |
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322 | pop si |
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323 | pop eax |
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324 | jnc @f |
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1065 | Lrz | 325 | ; read error - return |
326 | .readerr: |
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1132 | Lrz | 327 | pop ds |
1065 | Lrz | 328 | .readerr2: |
1132 | Lrz | 329 | pop di |
330 | mov ax, -1 |
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331 | mov dx, ax |
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332 | mov bx, 3 |
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333 | ret |
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1065 | Lrz | 334 | @@: |
335 | ; first item of the folder describes the folder itself |
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336 | ; do not cache too big folders: size < 64K and size <= (total cache size)/2 |
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1132 | Lrz | 337 | cmp word [bx+12], 0 |
338 | jnz .nocache |
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339 | mov cx, [cache_size] ; cx = cache size in sectors |
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340 | shr cx, 1 ; cx = (cache size)/2 |
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341 | cmp cx, 0x20 |
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342 | jae @f |
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343 | shl cx, 11 |
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344 | cmp [bx+10], cx |
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345 | ja .nocache |
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1065 | Lrz | 346 | @@: |
347 | ; we want to cache this folder; get space for it |
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1132 | Lrz | 348 | mov cx, [bx+10] |
349 | call cx_to_sectors |
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350 | jnz .yescache |
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1065 | Lrz | 351 | .nocache: |
1132 | Lrz | 352 | push dword [bx+10] |
353 | pop dword [cur_nocache_len] |
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354 | call lb_to_sector |
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355 | push ds |
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356 | pop es |
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357 | pop ds |
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1065 | Lrz | 358 | .nocache_loop: |
1132 | Lrz | 359 | push eax |
360 | mov dx, 1800h |
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361 | call scan_for_filename_in_sector |
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362 | mov cx, dx |
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363 | pop eax |
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364 | jnc .j_scandone |
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365 | sub cx, bx |
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366 | sub word [es:cur_nocache_len], cx |
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367 | sbb word [es:cur_nocache_len+2], 0 |
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368 | jb .j_scandone |
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369 | ja @f |
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370 | cmp word [es:cur_nocache_len], 0 |
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371 | jz .j_scandone |
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1065 | Lrz | 372 | @@: |
1132 | Lrz | 373 | mov cx, 1 |
374 | inc eax |
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375 | push es |
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376 | mov bx, 1000h |
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377 | call read_sectors |
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378 | pop es |
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379 | jc .readerr2 |
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380 | jmp .nocache_loop |
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1065 | Lrz | 381 | .j_scandone: |
1132 | Lrz | 382 | jmp .scandone |
1065 | Lrz | 383 | .yescache: |
1132 | Lrz | 384 | push bx |
385 | mov bx, [cachelist.head] |
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1065 | Lrz | 386 | .freeloop: |
1132 | Lrz | 387 | cmp cx, [size_rest] |
388 | jbe .sizeok |
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1065 | Lrz | 389 | @@: |
390 | ; if we are here: there is not enough free space, so we must delete old folders' data |
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391 | ; N.B. We know that after deleting some folders the space will be available (size <= (total cache size)/2). |
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392 | ; one loop iteration: delete data of one folder |
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1132 | Lrz | 393 | pusha |
394 | mov dx, [bx+10] |
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395 | mov es, dx ; es = segment of folder data to be deleted |
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396 | xor di, di |
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397 | mov ax, [bx+8] |
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398 | add ax, 0x7FF |
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399 | rcr ax, 1 |
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400 | shr ax, 10 |
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401 | push ax |
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402 | shl ax, 11-4 ; get number of paragraphs in folder data to be deleted |
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403 | mov cx, [cache_size] |
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404 | add cx, [cache_start] |
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405 | push ds |
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406 | push ax |
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407 | add ax, dx |
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408 | mov ds, ax |
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409 | pop ax |
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410 | shl cx, 11-4 |
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411 | sub cx, dx ; cx = number of paragraphs to be moved |
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412 | push si |
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413 | xor si, si |
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1065 | Lrz | 414 | ; move cx paragraphs from ds:si to es:di to get free space in the end of cache |
415 | @@: |
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1132 | Lrz | 416 | sub cx, 1000h |
417 | jbe @f |
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418 | push cx |
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419 | mov cx, 8000h |
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420 | rep movsw |
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421 | mov cx, ds |
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422 | add cx, 1000h |
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423 | mov ds, cx |
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424 | mov cx, es |
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425 | add cx, 1000h |
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426 | mov es, cx |
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427 | pop cx |
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428 | jmp @b |
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1065 | Lrz | 429 | @@: |
1132 | Lrz | 430 | add cx, 1000h |
431 | shl cx, 3 |
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432 | rep movsw |
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433 | pop si |
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434 | pop ds |
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1065 | Lrz | 435 | ; correct positions in cache for existing items |
1132 | Lrz | 436 | mov cx, 80h |
437 | mov di, 8400h |
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1065 | Lrz | 438 | .correct: |
1132 | Lrz | 439 | cmp [di+10], dx |
440 | jbe @f |
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441 | sub [di+10], ax |
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1065 | Lrz | 442 | @@: |
1132 | Lrz | 443 | add di, 12 |
444 | loop .correct |
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1065 | Lrz | 445 | ; some additional space is free now |
1132 | Lrz | 446 | pop ax |
447 | add [size_rest], ax |
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448 | sub [free_ptr], ax |
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1065 | Lrz | 449 | ; add cache item to the list of free items |
1132 | Lrz | 450 | mov dx, [bx] |
451 | mov ax, [free_cache_item] |
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452 | mov [bx], ax |
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453 | mov [free_cache_item], bx |
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454 | mov bx, dx |
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1065 | Lrz | 455 | ; current iteration done |
1132 | Lrz | 456 | popa |
457 | jmp .freeloop |
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1065 | Lrz | 458 | .sizeok: |
1132 | Lrz | 459 | mov [cachelist.head], bx |
460 | mov word [bx+2], cachelist |
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1065 | Lrz | 461 | ; allocate new item in cache |
1132 | Lrz | 462 | mov di, [free_cache_item] |
463 | test di, di |
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464 | jz .nofree |
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465 | push word [di] |
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466 | pop [free_cache_item] |
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467 | jmp @f |
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1065 | Lrz | 468 | .nofree: |
1132 | Lrz | 469 | mov di, [last_cache_item] |
470 | add [last_cache_item], 12 |
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1065 | Lrz | 471 | @@: |
1132 | Lrz | 472 | pop bx |
473 | push si di |
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474 | ; mov [di+4], eax ; start of folder |
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475 | scasd |
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476 | stosd |
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477 | push ax |
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478 | mov ax, [free_ptr] |
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479 | shl ax, 11-4 |
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480 | mov [di+10-8], ax |
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481 | mov es, ax |
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482 | pop ax |
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483 | add [free_ptr], cx |
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484 | sub [size_rest], cx |
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1065 | Lrz | 485 | ; read folder data |
486 | ; first sector is already in memory, 0000:bx |
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1132 | Lrz | 487 | pusha |
488 | mov cx, [bx+10] |
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489 | mov [di+8-8], cx ; folder size in bytes |
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490 | mov si, bx |
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491 | xor di, di |
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492 | mov cx, 0x1800 |
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493 | sub cx, si |
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494 | rep movsb |
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495 | pop ax |
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496 | push di |
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497 | popa |
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1065 | Lrz | 498 | ; read rest of folder |
1132 | Lrz | 499 | mov esi, dword [lb_per_sec] |
500 | add eax, esi |
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501 | dec si |
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502 | not si |
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503 | and ax, si |
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504 | mov si, word [bx+10] |
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505 | mov bx, di |
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506 | pop di |
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507 | sub si, bx |
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508 | jbe @f |
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509 | mov [cur_limit], esi |
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510 | call read_many_bytes |
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511 | pop si |
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512 | jnc .scan |
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513 | jmp .readerr |
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1065 | Lrz | 514 | @@: |
1132 | Lrz | 515 | pop si |
1065 | Lrz | 516 | .scan: |
517 | ; now we have required cache item; append it to the end of list |
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1132 | Lrz | 518 | mov bx, [cachelist.tail] |
519 | mov [cachelist.tail], di |
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520 | mov [di+2], bx |
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521 | mov word [di], cachelist |
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522 | mov [bx], di |
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1065 | Lrz | 523 | ; scan for given filename |
1132 | Lrz | 524 | mov es, [di+10] |
525 | mov dx, [di+8] |
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526 | pop ds |
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527 | xor bx, bx |
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528 | call scan_for_filename_in_sector |
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1065 | Lrz | 529 | .scandone: |
1132 | Lrz | 530 | push cs |
531 | pop es |
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532 | mov bx, 2000h |
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533 | cmp bx, [es:cur_desc_end] |
||
534 | jnz filefound |
||
1065 | Lrz | 535 | j_notfound: |
1132 | Lrz | 536 | jmp path_table_notfound |
1065 | Lrz | 537 | filefound: |
538 | @@: |
||
1132 | Lrz | 539 | lodsb |
540 | test al, al |
||
541 | jz @f |
||
542 | cmp al, '/' |
||
543 | jnz @b |
||
1065 | Lrz | 544 | @@: |
1132 | Lrz | 545 | mov cl, [es:bx+8] |
546 | test al, al |
||
547 | jz @f |
||
1065 | Lrz | 548 | ; parse next component of file name |
1132 | Lrz | 549 | test cl, 2 ; directory? |
550 | jz j_notfound |
||
551 | mov eax, [es:bx] |
||
552 | pop di |
||
553 | jmp parse_dir |
||
1065 | Lrz | 554 | @@: |
1132 | Lrz | 555 | test cl, 2 ; directory? |
556 | jnz j_notfound ; do not allow read directories as regular files |
||
1065 | Lrz | 557 | ; ok, now load the file |
1132 | Lrz | 558 | pop di |
559 | les bx, [di] |
||
560 | call normalize |
||
561 | movzx esi, word [di+4] ; esi = limit in 4K blocks |
||
562 | shl esi, 12 ; esi = limit in bytes |
||
563 | push cs |
||
564 | pop ds |
||
565 | mov [cur_limit], esi |
||
566 | mov di, 2000h |
||
1065 | Lrz | 567 | loadloop: |
1132 | Lrz | 568 | and [cur_start], 0 |
1065 | Lrz | 569 | .loadnew: |
1132 | Lrz | 570 | mov esi, [cur_limit] |
571 | mov eax, [cur_start] |
||
572 | add esi, eax |
||
573 | mov [overflow], 1 |
||
574 | sub esi, [di+4] |
||
575 | jb @f |
||
576 | xor esi, esi |
||
577 | dec [overflow] |
||
1065 | Lrz | 578 | @@: |
1132 | Lrz | 579 | add esi, [di+4] ; esi = number of bytes to read |
580 | mov [cur_start], esi |
||
581 | sub esi, eax |
||
582 | jz .loadcontinue |
||
583 | xor edx, edx |
||
584 | div dword [lb_size] ; eax = number of logical blocks to skip, |
||
585 | mov [first_byte], dx; [first_byte] = number of bytes to skip in 1st block |
||
586 | cmp byte [di+10], 0 |
||
587 | jnz .interleaved |
||
588 | add eax, [di] |
||
1065 | Lrz | 589 | ; read esi bytes from logical block eax to buffer es:bx |
1132 | Lrz | 590 | call read_many_bytes.with_first |
591 | jc .readerr3 |
||
1065 | Lrz | 592 | .loadcontinue: |
1132 | Lrz | 593 | mov [cur_chunk], di |
594 | add di, 11 |
||
595 | cmp di, [cur_desc_end] |
||
596 | jae @f |
||
597 | cmp [cur_limit], 0 |
||
598 | jnz loadloop |
||
1065 | Lrz | 599 | @@: |
1132 | Lrz | 600 | mov bx, [overflow] |
1065 | Lrz | 601 | .calclen: |
602 | ; calculate length of file |
||
1132 | Lrz | 603 | xor ax, ax |
604 | xor dx, dx |
||
605 | mov di, 2000h |
||
1065 | Lrz | 606 | @@: |
1132 | Lrz | 607 | add ax, [di+4] |
608 | adc dx, [di+6] |
||
609 | add di, 11 |
||
610 | cmp di, [cur_desc_end] |
||
611 | jb @b |
||
612 | ret |
||
1065 | Lrz | 613 | .interleaved: |
1132 | Lrz | 614 | mov [cur_unit_limit], esi |
615 | push esi |
||
1065 | Lrz | 616 | ; skip first blocks |
1132 | Lrz | 617 | movzx ecx, byte [di+9] ; Unit Size |
618 | movzx esi, byte [di+10] ; Interleave Gap |
||
619 | add si, cx |
||
620 | mov edx, [di] |
||
1065 | Lrz | 621 | @@: |
1132 | Lrz | 622 | sub eax, ecx |
623 | jb @f |
||
624 | add edx, esi |
||
625 | jmp @b |
||
1065 | Lrz | 626 | @@: |
1132 | Lrz | 627 | add ecx, eax ; ecx = number of logical blocks to skip |
628 | lea eax, [ecx+edx] ; eax = first logical block |
||
629 | pop esi |
||
1065 | Lrz | 630 | .interleaved_loop: |
631 | ; get number of bytes in current file unit |
||
1132 | Lrz | 632 | push eax |
633 | movzx eax, byte [di+9] |
||
634 | sub ax, cx |
||
635 | imul eax, dword [lb_size] |
||
636 | cmp eax, esi |
||
637 | ja .i2 |
||
1065 | Lrz | 638 | .i1: |
1132 | Lrz | 639 | xchg esi, eax |
1065 | Lrz | 640 | .i2: |
1132 | Lrz | 641 | pop eax |
642 | sub [cur_unit_limit], esi |
||
643 | push eax |
||
1065 | Lrz | 644 | ; read esi bytes from logical block eax to buffer es:bx |
1132 | Lrz | 645 | call read_many_bytes.with_first |
646 | pop eax |
||
647 | jnc @f |
||
1065 | Lrz | 648 | .readerr3: |
1132 | Lrz | 649 | mov bx, 3 |
650 | jmp .calclen |
||
1065 | Lrz | 651 | @@: |
1132 | Lrz | 652 | mov esi, [cur_unit_limit] |
653 | test esi, esi |
||
654 | jz .loadcontinue |
||
655 | movzx ecx, byte [di+9] ; add Unit Size |
||
656 | add cl, byte [di+10] ; add Interleave Gap |
||
657 | adc ch, 0 |
||
658 | add eax, ecx |
||
659 | xor cx, cx |
||
660 | mov [first_byte], cx |
||
661 | jmp .interleaved_loop |
||
1065 | Lrz | 662 | |
663 | cx_to_sectors: |
||
1132 | Lrz | 664 | add cx, 7FFh |
665 | rcr cx, 1 |
||
666 | shr cx, 10 |
||
667 | ret |
||
1065 | Lrz | 668 | |
669 | is_last_component: |
||
670 | ; in: ds:si -> name |
||
671 | ; out: CF set <=> current component is not last (=> folder) |
||
1132 | Lrz | 672 | push si |
1065 | Lrz | 673 | @@: |
1132 | Lrz | 674 | lodsb |
675 | test al, al |
||
676 | jz @f |
||
677 | cmp al, '/' |
||
678 | jnz @b |
||
679 | stc |
||
1065 | Lrz | 680 | @@: |
1132 | Lrz | 681 | pop si |
682 | ret |
||
1065 | Lrz | 683 | |
684 | test_filename1: |
||
685 | ; in: ds:si -> filename, es:di -> path table item |
||
686 | ; out: CF set <=> no match |
||
1132 | Lrz | 687 | pusha |
688 | mov cl, [es:di] |
||
689 | add di, 8 |
||
690 | jmp test_filename2.start |
||
1065 | Lrz | 691 | test_filename2: |
692 | ; in: ds:si -> filename, es:bx -> directory item |
||
693 | ; out: CF set <=> no match |
||
1132 | Lrz | 694 | pusha |
695 | mov cl, [es:bx+32] |
||
696 | lea di, [bx+33] |
||
1065 | Lrz | 697 | .start: |
1132 | Lrz | 698 | mov ch, 0 |
1065 | Lrz | 699 | @@: |
1132 | Lrz | 700 | lodsb |
701 | test al, al |
||
702 | jz .test1 |
||
703 | cmp al, '/' |
||
704 | jz .test1 |
||
705 | call toupper |
||
706 | mov ah, al |
||
707 | mov al, [es:di] |
||
708 | call toupper |
||
709 | inc di |
||
710 | cmp al, ah |
||
711 | loopz @b |
||
712 | jnz .next1 |
||
1065 | Lrz | 713 | ; if we have reached this point: current name is done |
1132 | Lrz | 714 | lodsb |
715 | test al, al |
||
716 | jz .ret |
||
717 | cmp al, '/' |
||
718 | jz .ret |
||
1065 | Lrz | 719 | ; if we have reached this point: current name is done, but input name continues |
720 | ; so they do not match |
||
1132 | Lrz | 721 | jmp .next1 |
1065 | Lrz | 722 | .test1: |
723 | ; if we have reached this point: input name is done, but current name continues |
||
724 | ; "filename.ext;version" in ISO-9660 represents file "filename.ext" |
||
725 | ; "filename." and "filename.;version" are also possible for "filename" |
||
1132 | Lrz | 726 | cmp byte [es:di], '.' |
727 | jnz @f |
||
728 | inc di |
||
729 | dec cx |
||
730 | jz .ret |
||
1065 | Lrz | 731 | @@: |
1132 | Lrz | 732 | cmp byte [es:di], ';' |
733 | jnz .next1 |
||
734 | jmp .ret |
||
1065 | Lrz | 735 | .next1: |
1132 | Lrz | 736 | stc |
1065 | Lrz | 737 | .ret: |
1132 | Lrz | 738 | popa |
739 | ret |
||
1065 | Lrz | 740 | |
741 | toupper: |
||
742 | ; in: al=symbol |
||
743 | ; out: al=symbol in uppercase |
||
1132 | Lrz | 744 | cmp al, 'a' |
745 | jb .ret |
||
746 | cmp al, 'z' |
||
747 | ja .ret |
||
748 | sub al, 'a'-'A' |
||
1065 | Lrz | 749 | .ret: |
1132 | Lrz | 750 | ret |
1065 | Lrz | 751 | |
752 | scan_for_filename_in_sector: |
||
753 | ; in: ds:si->filename, es:bx->folder data, dx=limit |
||
754 | ; out: CF=0 if found |
||
1132 | Lrz | 755 | push bx |
1065 | Lrz | 756 | .loope: |
1132 | Lrz | 757 | push bx |
1065 | Lrz | 758 | .loop: |
1132 | Lrz | 759 | cmp bx, dx |
760 | jae .notfound |
||
761 | cmp byte [es:bx], 0 |
||
762 | jz .loopd |
||
763 | test byte [es:bx+25], 4 ; ignore files with Associated bit |
||
764 | jnz .next |
||
765 | call test_filename2 |
||
766 | jc .next |
||
767 | push ds es di |
||
768 | push es |
||
769 | pop ds |
||
770 | push cs |
||
771 | pop es |
||
772 | mov di, [es:cur_desc_end] |
||
773 | movzx eax, byte [bx+1] |
||
774 | add eax, [bx+2] |
||
775 | stosd ; first logical block |
||
776 | mov eax, [bx+10] |
||
777 | stosd ; length |
||
778 | mov al, [bx+25] |
||
779 | stosb ; flags |
||
780 | mov ax, [bx+26] |
||
781 | stosw ; File Unit size, Interleave Gap size |
||
782 | mov [es:cur_desc_end], di |
||
783 | cmp di, 3000h |
||
784 | pop di es ds |
||
785 | jae .done |
||
786 | test byte [es:bx+25], 80h |
||
787 | jz .done |
||
1065 | Lrz | 788 | .next: |
1132 | Lrz | 789 | add bl, [es:bx] |
790 | adc bh, 0 |
||
791 | jmp .loop |
||
1065 | Lrz | 792 | .loopd: |
1132 | Lrz | 793 | mov ax, bx |
794 | pop bx |
||
1065 | Lrz | 795 | @@: |
1132 | Lrz | 796 | add bx, [cs:lb_size] |
797 | jz .done2 |
||
798 | cmp bx, ax |
||
799 | jb @b |
||
800 | jmp .loope |
||
1065 | Lrz | 801 | .notfound: |
1132 | Lrz | 802 | stc |
1065 | Lrz | 803 | .done: |
1132 | Lrz | 804 | pop bx |
1065 | Lrz | 805 | .done2: |
1132 | Lrz | 806 | pop bx |
807 | ret |
||
1065 | Lrz | 808 | |
809 | lb_to_sector: |
||
1132 | Lrz | 810 | xor edx, edx |
811 | div dword [lb_per_sec] |
||
812 | ret |
||
1065 | Lrz | 813 | |
814 | load_phys_sector_for_lb_force: |
||
815 | ; in: eax = logical block, ds=0 |
||
816 | ; in: si=0 - accept 0 logical blocks, otherwise force read at least 1 |
||
817 | ; out: 0000:1000 = physical sector data; si -> logical block |
||
818 | ; out: eax = next physical sector |
||
819 | ; out: CF=1 if read error |
||
820 | ; destroys cx |
||
821 | ; this procedure reads 0-3 or 1-4 logical blocks, up to the end of physical sector |
||
1132 | Lrz | 822 | call lb_to_sector |
823 | or si, dx |
||
824 | jnz @f |
||
825 | mov si, 1800h |
||
826 | jmp .done |
||
1065 | Lrz | 827 | @@: |
1132 | Lrz | 828 | mov si, 1000h |
829 | imul dx, [lb_size] |
||
830 | add si, dx |
||
831 | mov cx, 1 |
||
832 | push es bx |
||
833 | push ds |
||
834 | pop es |
||
835 | mov bx, 1000h |
||
836 | call read_sectors |
||
837 | pop bx es |
||
838 | inc eax |
||
1065 | Lrz | 839 | .done: |
1132 | Lrz | 840 | ret |
1065 | Lrz | 841 | |
842 | normalize: |
||
843 | ; in: es:bx = far pointer |
||
844 | ; out: es:bx = normalized pointer (i.e. 0 <= bx < 0x10) |
||
1132 | Lrz | 845 | push ax bx |
846 | mov ax, es |
||
847 | shr bx, 4 |
||
848 | add ax, bx |
||
849 | mov es, ax |
||
850 | pop bx ax |
||
851 | and bx, 0x0F |
||
852 | ret |
||
1065 | Lrz | 853 | |
854 | read_many_bytes: |
||
1132 | Lrz | 855 | and [first_byte], 0 |
1065 | Lrz | 856 | read_many_bytes.with_first: |
857 | ; read esi bytes from logical block dx:ax to buffer es:bx |
||
858 | ; out: CF=1 <=> disk error |
||
1132 | Lrz | 859 | push di |
1065 | Lrz | 860 | ; load first physical sector |
1132 | Lrz | 861 | push bx si |
862 | mov si, [first_byte] |
||
863 | call load_phys_sector_for_lb_force |
||
864 | jnc @f |
||
865 | pop si bx |
||
1065 | Lrz | 866 | .ret: |
1132 | Lrz | 867 | pop di |
868 | ret |
||
1065 | Lrz | 869 | @@: |
1132 | Lrz | 870 | add si, [first_byte] |
871 | mov ecx, 1800h |
||
872 | sub cx, si |
||
873 | mov ebx, esi |
||
874 | pop bx |
||
875 | sub ebx, ecx |
||
876 | jnc @f |
||
877 | add cx, bx |
||
878 | xor ebx, ebx |
||
1065 | Lrz | 879 | @@: |
1132 | Lrz | 880 | pop di |
881 | sub [cur_limit], ecx |
||
882 | rep movsb |
||
883 | mov esi, ebx |
||
884 | mov bx, di |
||
885 | call normalize |
||
1065 | Lrz | 886 | ; load other physical sectors |
887 | ; read esi bytes from physical sector eax to buffer es:bx |
||
1132 | Lrz | 888 | test esi, esi |
889 | jz .ret |
||
890 | push esi |
||
891 | add esi, 0x7FF |
||
892 | and si, not 0x7FF |
||
893 | cmp esi, [cur_limit] |
||
894 | jbe .okplace |
||
1065 | Lrz | 895 | .noplace: |
1132 | Lrz | 896 | sub esi, 800h |
1065 | Lrz | 897 | .okplace: |
1132 | Lrz | 898 | shr esi, 11 ; si = number of sectors |
899 | mov cx, si |
||
900 | jz @f |
||
901 | call read_sectors |
||
1065 | Lrz | 902 | @@: |
1132 | Lrz | 903 | pop esi |
904 | jc .ret |
||
905 | movzx ecx, cx |
||
906 | add eax, ecx |
||
907 | shl ecx, 11 |
||
908 | sub [cur_limit], ecx |
||
909 | sub esi, ecx |
||
910 | jc .big |
||
911 | jz .nopost |
||
912 | push bx es |
||
913 | push ds |
||
914 | pop es |
||
915 | mov bx, 1000h |
||
916 | mov cx, 1 |
||
917 | call read_sectors |
||
918 | pop es di |
||
919 | jc .ret2 |
||
920 | mov cx, si |
||
921 | mov si, 1000h |
||
922 | sub word [cur_limit], cx |
||
923 | sbb word [cur_limit+2], 0 |
||
924 | rep movsb |
||
925 | mov bx, di |
||
926 | call normalize |
||
1065 | Lrz | 927 | .nopost: |
1132 | Lrz | 928 | clc |
1065 | Lrz | 929 | .ret2: |
1132 | Lrz | 930 | pop di |
931 | ret |
||
1065 | Lrz | 932 | .big: |
1132 | Lrz | 933 | mov ax, es |
934 | sub ax, 80h |
||
935 | mov es, ax |
||
936 | add bx, 800h |
||
937 | add bx, si |
||
938 | call normalize |
||
939 | sub [cur_limit], esi |
||
940 | jmp .nopost |
||
1065 | Lrz | 941 | |
942 | ; Callback function for secondary loader |
||
943 | callback: |
||
944 | ; in: ax = function number; only function 1 is defined for now |
||
1132 | Lrz | 945 | dec ax |
946 | jz callback_readfile |
||
947 | dec ax |
||
948 | jz callback_continueread |
||
949 | stc ; unsupported function |
||
950 | retf |
||
1065 | Lrz | 951 | |
952 | callback_readfile: |
||
953 | ; function 1: read file |
||
954 | ; in: ds:di -> information structure |
||
1132 | Lrz | 955 | ; dw:dw address |
956 | ; dw limit in 4Kb blocks (0x1000 bytes) (must be non-zero and not greater than 0x100) |
||
957 | ; ASCIIZ name |
||
1065 | Lrz | 958 | ; 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 |
959 | ; out: dx:ax = file size (0xFFFFFFFF if file was not found) |
||
1132 | Lrz | 960 | call load_file |
961 | clc ; function is supported |
||
962 | retf |
||
1065 | Lrz | 963 | |
964 | callback_continueread: |
||
965 | ; function 2: continue to read file |
||
966 | ; in: ds:di -> information structure |
||
1132 | Lrz | 967 | ; dw:dw address |
968 | ; dw limit in 4Kb blocks (0x1000 bytes) (must be non-zero and not greater than 0x100) |
||
1065 | Lrz | 969 | ; out: bx=0 - ok, bx=1 - file is too big, only part of file was loaded, bx=3 - read error |
970 | ; out: dx:ax = file size |
||
1132 | Lrz | 971 | les bx, [di] |
972 | call normalize |
||
973 | movzx esi, word [di+4] ; si = limit in 4K blocks |
||
974 | shl esi, 12 ; bp:si = limit in bytes |
||
975 | push cs |
||
976 | pop ds |
||
977 | mov [cur_limit], esi |
||
978 | mov di, [cur_chunk] |
||
979 | call loadloop.loadnew |
||
980 | clc ; function is supported |
||
981 | retf |
||
1065 | Lrz | 982 | |
983 | secondary_loader_info: |
||
1132 | Lrz | 984 | dw 0, 0x1000 |
985 | dw 0x30000 / 0x1000 |
||
986 | db 'kord/loader',0 |
||
987 | aKernelNotFound db 'Fatal error: cannot load the secondary loader',0 |
||
1065 | Lrz | 988 | |
989 | align 2 |
||
990 | cachelist: |
||
1132 | Lrz | 991 | .head dw cachelist |
992 | .tail dw cachelist |
||
993 | free_cache_item dw 0 |
||
994 | last_cache_item dw 0x8400 |
||
1065 | Lrz | 995 | |
1132 | Lrz | 996 | use_path_table db 0 |
997 | bootdrive db ? |
||
1065 | Lrz | 998 | align 2 |
1132 | Lrz | 999 | lb_size dw ? ; Logical Block size in bytes |
1000 | dw 0 ; to allow access dword [lb_size] |
||
1001 | lb_per_sec dw ? ; Logical Blocks per physical sector |
||
1002 | dw 0 ; to allow access dword [lb_per_sec] |
||
1003 | free_ptr dw ? ; first free block in cache (cache block = sector = 0x800 bytes) |
||
1004 | size_rest dw ? ; free space in cache (in blocks) |
||
1005 | cache_size dw ? |
||
1006 | cache_start dw ? |
||
1007 | pathtable_size dw ? |
||
1008 | pathtable_start dw ? |
||
1009 | root_location dd ? |
||
1010 | cur_desc_end dw ? |
||
1011 | cur_nocache_len dd ? |
||
1012 | cur_limit dd ? |
||
1013 | cur_unit_limit dd ? |
||
1014 | overflow dw ? |
||
1015 | cur_chunk dw ? |
||
1016 | first_byte dw ? |
||
1017 | cur_start dd ? |
||
1065 | Lrz | 1018 | |
1132 | Lrz | 1019 | ;times 83FEh-$ db 0 |
1020 | db 43h |
||
1065 | Lrz | 1021 | ; just to make file 2048 bytes long :) |
1132 | Lrz | 1022 | db 'd' xor 'i' xor 'a' xor 'm' xor 'o' xor 'n' xor 'd' |
1065 | Lrz | 1023 | |
1132 | Lrz | 1024 | dw 0xAA55 ; this is not required for CD, but to be consistent...=>>=>=>=>=>=>=>> |