1 | ; File name : DriveXlate.asm
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2 | ; Project name : IDE BIOS
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3 | ; Created date : 15.3.2010
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4 | ; Last update : 2.4.2010
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5 | ; Author : Tomi Tilli
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6 | ; Description : Functions for swapping drive letters.
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7 |
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8 | ; Section containing code
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9 | SECTION .text
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10 |
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11 | ;--------------------------------------------------------------------
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12 | ; Translates drive number when entering INT 13h.
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13 | ;
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14 | ; DriveXlate_WhenEnteringInt13h
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15 | ; Parameters:
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16 | ; DL: Drive number to be possibly translated
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17 | ; DS: RAMVARS segment
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18 | ; Returns:
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19 | ; DL: Translated drive number
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20 | ; Corrupts registers:
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21 | ; DI
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22 | ;--------------------------------------------------------------------
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23 | ALIGN JUMP_ALIGN
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24 | DriveXlate_WhenEnteringInt13h:
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25 | inc BYTE [RAMVARS.xlateVars+XLATEVARS.bRecurCnt]
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26 | cmp BYTE [RAMVARS.xlateVars+XLATEVARS.bRecurCnt], 1
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27 | je SHORT DriveXlate_ToOrBack
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28 | ret
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29 |
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30 |
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31 | ;--------------------------------------------------------------------
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32 | ; Translates drive number when leaving INT 13h.
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33 | ;
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34 | ; DriveXlate_WhenLeavingInt13h
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35 | ; Parameters:
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36 | ; DL: Drive number to be possibly translated
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37 | ; DS: RAMVARS segment
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38 | ; Returns:
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39 | ; DL: Translated drive number
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40 | ; Corrupts registers:
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41 | ; DI
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42 | ;--------------------------------------------------------------------
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43 | ALIGN JUMP_ALIGN
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44 | DriveXlate_WhenLeavingInt13h:
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45 | dec BYTE [RAMVARS.xlateVars+XLATEVARS.bRecurCnt]
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46 | jz SHORT DriveXlate_ToOrBack
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47 | ret
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48 |
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49 |
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50 | ;--------------------------------------------------------------------
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51 | ; Translates drive number to or back.
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52 | ;
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53 | ; DriveXlate_ToOrBack
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54 | ; Parameters:
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55 | ; DL: Drive number to be possibly translated
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56 | ; DS: RAMVARS segment
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57 | ; Returns:
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58 | ; DL: Translated drive number
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59 | ; Corrupts registers:
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60 | ; DI
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61 | ;--------------------------------------------------------------------
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62 | ALIGN JUMP_ALIGN
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63 | DriveXlate_ToOrBack:
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64 | test BYTE [cs:ROMVARS.wFlags], FLG_ROMVARS_DRVXLAT
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65 | jz SHORT .Return ; Return if translation disabled
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66 | xchg di, ax ; Backup AX
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67 | call DriveXlate_SwapFloppyDriveOrHardDisk
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68 | xchg ax, di
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69 | .Return:
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70 | ret
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71 |
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72 |
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73 | ;--------------------------------------------------------------------
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74 | ; Swaps Floppy Drive or Hard Disk number.
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75 | ;
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76 | ; DriveXlate_SwapFloppyDriveOrHardDisk
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77 | ; Parameters:
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78 | ; DL: Drive number to be possibly swapped
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79 | ; DS: RAMVARS segment
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80 | ; Returns:
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81 | ; DL: Translated drive number
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82 | ; Corrupts registers:
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83 | ; AX
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84 | ;--------------------------------------------------------------------
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85 | ALIGN JUMP_ALIGN
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86 | DriveXlate_SwapFloppyDriveOrHardDisk:
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87 | test dl, 80h ; Hard disk?
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88 | jnz SHORT DriveXlate_SwapHardDisk ; If so, jump to swap
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89 | ; Fall to DriveXlate_SwapFloppyDrive
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90 |
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91 | ;--------------------------------------------------------------------
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92 | ; Swaps Floppy Drive number.
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93 | ;
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94 | ; DriveXlate_SwapFloppyDrive
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95 | ; Parameters:
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96 | ; DL: Drive number to be possibly swapped
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97 | ; DS: RAMVARS segment
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98 | ; Returns:
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99 | ; DL: Translated drive number
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100 | ; Corrupts registers:
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101 | ; AX
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102 | ;--------------------------------------------------------------------
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103 | ;ALIGN JUMP_ALIGN
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104 | DriveXlate_SwapFloppyDrive:
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105 | eMOVZX ax, BYTE [RAMVARS.xlateVars+XLATEVARS.bFDSwap]
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106 | jmp SHORT DriveXlate_SwapDrive
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107 |
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108 | ;--------------------------------------------------------------------
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109 | ; Swaps Hard Disk number.
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110 | ;
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111 | ; DriveXlate_SwapHardDisk
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112 | ; Parameters:
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113 | ; DL: Drive number to be possibly swapped
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114 | ; DS: RAMVARS segment
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115 | ; Returns:
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116 | ; DL: Translated drive number
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117 | ; Corrupts registers:
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118 | ; AX
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119 | ;--------------------------------------------------------------------
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120 | ALIGN JUMP_ALIGN
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121 | DriveXlate_SwapHardDisk:
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122 | mov ah, 80h
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123 | mov al, BYTE [RAMVARS.xlateVars+XLATEVARS.bHDSwap]
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124 | ; Fall to DriveXlate_SwapDrive
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125 |
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126 | ;--------------------------------------------------------------------
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127 | ; Swaps Hard Disk or Floppy Drive number.
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128 | ;
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129 | ; DriveXlate_SwapDrive
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130 | ; Parameters:
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131 | ; AL: Drive number to swap to 00h/80h
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132 | ; AH: 00h/80h to be swapped to stored drive number
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133 | ; DL: Drive number to be possibly swapped
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134 | ; Returns:
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135 | ; DL: Translated drive number
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136 | ; Corrupts registers:
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137 | ; Nothing
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138 | ;--------------------------------------------------------------------
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139 | ;ALIGN JUMP_ALIGN
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140 | DriveXlate_SwapDrive:
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141 | cmp ah, dl ; Swap DL from 00h/80h to xxh?
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142 | je SHORT .SwapToXXhInAL
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143 | cmp al, dl ; Swap DL from xxh to 00h/80h?
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144 | je SHORT .SwapTo00hOr80hInAH
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145 | ret
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146 | ALIGN JUMP_ALIGN
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147 | .SwapTo00hOr80hInAH:
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148 | mov dl, ah
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149 | ret
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150 | ALIGN JUMP_ALIGN
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151 | .SwapToXXhInAL:
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152 | mov dl, al
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153 | ret
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154 |
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155 |
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156 | ;--------------------------------------------------------------------
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157 | ; Resets drive swapping variables to defaults (no swapping).
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158 | ;
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159 | ; DriveXlate_Reset
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160 | ; Parameters:
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161 | ; DS: RAMVARS segment
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162 | ; Returns:
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163 | ; Nothing
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164 | ; Corrupts registers:
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165 | ; AX
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166 | ;--------------------------------------------------------------------
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167 | ALIGN JUMP_ALIGN
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168 | DriveXlate_Reset:
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169 | mov WORD [RAMVARS.xlateVars], 8000h ; .bFDSwap and .bHDSwap
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170 | mov BYTE [RAMVARS.xlateVars+XLATEVARS.bRecurCnt], 0
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171 | ret
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172 |
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173 |
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174 | ;--------------------------------------------------------------------
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175 | ; Stores drive to be swapped.
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176 | ;
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177 | ; DriveXlate_SetDriveToSwap
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178 | ; Parameters:
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179 | ; DL: Drive to swap to 00h or 80h
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180 | ; DS: RAMVARS segment
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181 | ; Returns:
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182 | ; Nothing
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183 | ; Corrupts registers:
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184 | ; Nothing
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185 | ;--------------------------------------------------------------------
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186 | ALIGN JUMP_ALIGN
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187 | DriveXlate_SetDriveToSwap:
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188 | test dl, 80h ; Floppy drive?
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189 | jnz SHORT DriveXlate_SetHardDiskToSwap
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190 | ; Fall to DriveXlate_SetFloppyDriveToSwap
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191 |
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192 | ;--------------------------------------------------------------------
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193 | ; Stores floppy drive to be swapped.
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194 | ;
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195 | ; DriveXlate_SetFloppyDriveToSwap
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196 | ; Parameters:
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197 | ; DL: Drive to swap to 00h
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198 | ; DS: RAMVARS segment
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199 | ; Returns:
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200 | ; Nothing
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201 | ; Corrupts registers:
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202 | ; Nothing
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203 | ;--------------------------------------------------------------------
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204 | ALIGN JUMP_ALIGN
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205 | DriveXlate_SetFloppyDriveToSwap:
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206 | mov [RAMVARS.xlateVars+XLATEVARS.bFDSwap], dl
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207 | ret
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208 |
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209 | ;--------------------------------------------------------------------
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210 | ; Stores hard disk to be swapped.
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211 | ;
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212 | ; DriveXlate_SetHardDiskToSwap
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213 | ; Parameters:
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214 | ; DL: Drive to swap to 80h
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215 | ; DS: RAMVARS segment
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216 | ; Returns:
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217 | ; Nothing
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218 | ; Corrupts registers:
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219 | ; Nothing
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220 | ;--------------------------------------------------------------------
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221 | ALIGN JUMP_ALIGN
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222 | DriveXlate_SetHardDiskToSwap:
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223 | mov [RAMVARS.xlateVars+XLATEVARS.bHDSwap], dl
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224 | ret
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225 |
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226 |
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227 | ;--------------------------------------------------------------------
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228 | ; Checks if INT 13h function returns some value in DL
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229 | ; (other than the drive number that was also parameter).
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230 | ;
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231 | ; DriveXlate_DoesFunctionReturnSomethingInDL
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232 | ; Parameters:
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233 | ; AH: INT 13h BIOS Function
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234 | ; DL: Drive number
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235 | ; Returns:
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236 | ; CF: Set if something is returned in DL
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237 | ; Cleared if only drive number parameter is returned in DL
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238 | ; Corrupts registers:
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239 | ; Nothing
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240 | ;--------------------------------------------------------------------
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241 | ALIGN JUMP_ALIGN
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242 | DriveXlate_DoesFunctionReturnSomethingInDL:
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243 | cmp ah, 08h ; AH=08h, Read Disk Drive Parameters?
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244 | je SHORT DriveXlate_FunctionReturnsSomethingInDL
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245 | test dl, 80h
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246 | jz SHORT DriveXlate_DoesFloppyFunctionReturnSomethingInDL
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247 | ; Fall to DriveXlate_DoesHardDiskFunctionReturnSomethingInDL
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248 |
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249 | ;--------------------------------------------------------------------
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250 | ; Checks if INT 13h hard disk or floppy drive function returns some
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251 | ; value in DL other than the drive number that was also parameter).
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252 | ; Some functions return different values for hard disks and floppy drives.
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253 | ;
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254 | ; DriveXlate_DoesHardDiskFunctionReturnSomethingInDL
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255 | ; DriveXlate_DoesFloppyFunctionReturnSomethingInDL
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256 | ; Parameters:
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257 | ; AH: INT 13h BIOS Function
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258 | ; DL: Hard Disk number
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259 | ; Returns:
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260 | ; CF: Set if something is returned in DL
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261 | ; Cleared if only drive number parameter is returned in DL
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262 | ; Corrupts registers:
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263 | ; Nothing
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264 | ;--------------------------------------------------------------------
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265 | ; ALIGN JUMP_ALIGN
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266 | DriveXlate_DoesHardDiskFunctionReturnSomethingInDL:
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267 | cmp ah, 15h ; AH=15h, Read Disk Drive Size?
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268 | je SHORT DriveXlate_FunctionReturnsSomethingInDL
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269 | DriveXlate_DoesFloppyFunctionReturnSomethingInDL:
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270 | clc
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271 | ret
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272 |
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273 | ALIGN JUMP_ALIGN
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274 | DriveXlate_FunctionReturnsSomethingInDL:
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275 | stc
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276 | ret
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