1 | ; File name : FindDPT.asm |
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2 | ; Project name : IDE BIOS |
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3 | ; Created date : 14.3.2010 |
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4 | ; Last update : 12.4.2010 |
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5 | ; Author : Tomi Tilli |
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6 | ; Description : Functions for finding Disk Parameter Table. |
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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 | ; Finds pointer to first unused Disk Parameter Table. |
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13 | ; |
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14 | ; FindDPT_ForNewDrive |
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15 | ; Parameters: |
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16 | ; DS: RAMVARS segment |
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17 | ; Returns: |
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18 | ; DS:DI: Ptr to first unused DPT |
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19 | ; Corrupts registers: |
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20 | ; Nothing |
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21 | ;-------------------------------------------------------------------- |
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22 | ALIGN JUMP_ALIGN |
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23 | FindDPT_ForNewDrive: |
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24 | push si |
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25 | mov si, FindDPT_ReturnWrongDPT |
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26 | jmp SHORT FindDPT_StartIterationAndReturnAfterDone |
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27 | |
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28 | |
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29 | ;-------------------------------------------------------------------- |
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30 | ; Finds Disk Parameter Table for |
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31 | ; Master or Slave drive at wanted port. |
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32 | ; |
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33 | ; FindDPT_ForIdeSlaveAtPort |
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34 | ; FindDPT_ForIdeMasterAtPort |
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35 | ; Parameters: |
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36 | ; DX: IDE Base Port address |
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37 | ; DS: RAMVARS segment |
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38 | ; Returns: |
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39 | ; DL: Drive number (if DPT found) |
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40 | ; DS:DI: Ptr to DPT |
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41 | ; CF: Set if wanted DPT found |
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42 | ; Cleared if DPT not found |
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43 | ; Corrupts registers: |
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44 | ; Nothing |
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45 | ;-------------------------------------------------------------------- |
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46 | ALIGN JUMP_ALIGN |
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47 | FindDPT_ForIdeSlaveAtPort: |
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48 | push si |
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49 | mov si, FindDPT_IterateToSlaveAtPortCallback |
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50 | jmp SHORT FindDPT_StartIterationAndReturnAfterDone |
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51 | |
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52 | ALIGN JUMP_ALIGN |
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53 | FindDPT_ForIdeMasterAtPort: |
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54 | push si |
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55 | mov si, FindDPT_IterateToMasterAtPortCallback |
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56 | jmp SHORT FindDPT_StartIterationAndReturnAfterDone |
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57 | |
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58 | ;-------------------------------------------------------------------- |
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59 | ; Iteration callback for finding DPT using |
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60 | ; IDE base port for Master or Slave drive. |
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61 | ; |
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62 | ; FindDPT_IterateToSlaveAtPortCallback |
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63 | ; FindDPT_IterateToMasterAtPortCallback |
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64 | ; Parameters: |
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65 | ; DX: IDE Base Port address |
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66 | ; DS:DI: Ptr to DPT to examine |
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67 | ; Returns: |
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68 | ; DL: Drive number if correct DPT |
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69 | ; CF: Set if wanted DPT found |
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70 | ; Cleared if wrong DPT |
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71 | ; Corrupts registers: |
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72 | ; Nothing |
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73 | ;-------------------------------------------------------------------- |
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74 | ALIGN JUMP_ALIGN |
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75 | FindDPT_IterateToSlaveAtPortCallback: |
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76 | test BYTE [di+DPT.bDrvSel], FLG_IDE_DRVHD_DRV |
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77 | jnz SHORT FindDPT_IterateToMasterOrSlaveAtPortCallback |
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78 | jmp SHORT FindDPT_ReturnWrongDPT ; Return if master drive |
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79 | |
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80 | ALIGN JUMP_ALIGN |
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81 | FindDPT_IterateToMasterAtPortCallback: |
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82 | test BYTE [di+DPT.bDrvSel], FLG_IDE_DRVHD_DRV |
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83 | jnz SHORT FindDPT_ReturnWrongDPT ; Return if slave drive |
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84 | |
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85 | ; If BIOS partitioned, ignore all but first partition |
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86 | ALIGN JUMP_ALIGN |
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87 | FindDPT_IterateToMasterOrSlaveAtPortCallback: |
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88 | test BYTE [di+DPT.bFlags], FLG_DPT_PARTITION |
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89 | jz SHORT .CompareBasePortAddress |
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90 | test BYTE [di+DPT.bFlags], FLG_DPT_FIRSTPART |
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91 | jz SHORT FindDPT_ReturnWrongDPT |
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92 | ALIGN JUMP_ALIGN |
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93 | .CompareBasePortAddress: |
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94 | push bx |
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95 | eMOVZX bx, BYTE [di+DPT.bIdeOff] ; CS:BX now points to IDEVARS |
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96 | cmp dx, [cs:bx+IDEVARS.wPort] ; Wanted port? |
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97 | pop bx |
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98 | jne SHORT FindDPT_ReturnWrongDPT |
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99 | mov dl, [di+DPT.bDrvNum] ; Load drive number |
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100 | stc ; Set CF since wanted DPT |
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101 | ret |
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102 | |
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103 | |
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104 | ;-------------------------------------------------------------------- |
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105 | ; Finds Disk Parameter Table for drive number. |
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106 | ; IDE Base Port address will be stored to RAMVARS if correct DPT is found. |
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107 | ; |
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108 | ; FindDPT_ForDriveNumber |
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109 | ; Parameters: |
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110 | ; DL: Drive number |
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111 | ; DS: RAMVARS segment |
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112 | ; Returns: |
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113 | ; DS:DI: Ptr to DPT |
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114 | ; CF: Set if wanted DPT found |
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115 | ; Cleared if DPT not found |
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116 | ; Corrupts registers: |
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117 | ; Nothing |
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118 | ;-------------------------------------------------------------------- |
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119 | ALIGN JUMP_ALIGN |
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120 | FindDPT_ForDriveNumber: |
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121 | push si |
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122 | mov si, FindDPT_IterateToDriveNumberCallback |
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123 | FindDPT_StartIterationAndReturnAfterDone: |
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124 | call FindDPT_IterateAllDPTs |
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125 | pop si |
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126 | ret |
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127 | |
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128 | ;-------------------------------------------------------------------- |
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129 | ; Iteration callback for finding DPT for drive number. |
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130 | ; |
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131 | ; FindDPT_IterateToDriveNumberCallback |
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132 | ; Parameters: |
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133 | ; DL: Drive number to search for |
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134 | ; DS:DI: Ptr to DPT to examine |
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135 | ; Returns: |
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136 | ; CF: Set if wanted DPT found |
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137 | ; Cleared if wrong DPT |
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138 | ; Corrupts registers: |
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139 | ; Nothing |
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140 | ;-------------------------------------------------------------------- |
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141 | ALIGN JUMP_ALIGN |
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142 | FindDPT_IterateToDriveNumberCallback: |
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143 | cmp dl, [di+DPT.bDrvNum] ; Wanted DPT found? |
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144 | je SHORT FindDPT_RightDriveNumber ; If so, return |
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145 | FindDPT_ReturnWrongDPT: |
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146 | clc ; Clear CF since wrong DPT |
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147 | ret |
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148 | ALIGN JUMP_ALIGN |
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149 | FindDPT_RightDriveNumber: |
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150 | push bx |
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151 | eMOVZX bx, BYTE [di+DPT.bIdeOff] ; CS:BX now points to IDEVARS |
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152 | mov bx, [cs:bx+IDEVARS.wPort] ; Load IDE Base Port address... |
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153 | mov [RAMVARS.wIdeBase], bx ; ...and store it to RAMVARS |
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154 | pop bx |
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155 | stc |
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156 | ret |
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157 | |
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158 | |
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159 | ;-------------------------------------------------------------------- |
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160 | ; Iterates all Disk Parameter Tables. |
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161 | ; |
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162 | ; FindDPT_IterateAllDPTs |
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163 | ; Parameters: |
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164 | ; BX,DX: Parameters to callback function |
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165 | ; CS:SI: Ptr to callback function |
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166 | ; DS: RAMVARS segment |
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167 | ; Returns: |
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168 | ; DS:DI: Ptr to wanted DPT (if found) |
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169 | ; CF: Set if wanted DPT found |
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170 | ; Cleared if DPT not found |
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171 | ; Corrupts registers: |
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172 | ; Nothing, unless corrupted by callback function |
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173 | ;-------------------------------------------------------------------- |
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174 | ALIGN JUMP_ALIGN |
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175 | FindDPT_IterateAllDPTs: |
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176 | push ax |
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177 | push cx |
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178 | call FindDPT_PointToFirstDPT ; Point DS:DI to first DPT |
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179 | eMOVZX cx, BYTE [RAMVARS.bDrvCnt] ; Load number of drives |
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180 | xor ax, ax ; Zero AX for DPT size and clear CF |
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181 | jcxz .Return ; Return if no drives |
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182 | ALIGN JUMP_ALIGN |
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183 | .LoopWhileDPTsLeft: |
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184 | call si ; Is wanted DPT? |
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185 | jc SHORT .Return ; If so, return |
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186 | mov al, [di+DPT.bSize] ; Load DPT size to AX |
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187 | add di, ax ; Point to next DPT |
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188 | loop .LoopWhileDPTsLeft ; Check next DPT |
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189 | clc ; Clear CF since DPT not found |
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190 | ALIGN JUMP_ALIGN |
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191 | .Return: |
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192 | pop cx |
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193 | pop ax |
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194 | ret |
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195 | |
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196 | |
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197 | ;-------------------------------------------------------------------- |
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198 | ; Sets DI to point to first Disk Parameter Table. |
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199 | ; |
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200 | ; FindDPT_PointToFirstDPT |
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201 | ; Parameters: |
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202 | ; Nothing |
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203 | ; Returns: |
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204 | ; DI: Offset to first DPT (even if unused) |
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205 | ; Corrupts registers: |
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206 | ; Nothing |
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207 | ;-------------------------------------------------------------------- |
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208 | ALIGN JUMP_ALIGN |
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209 | FindDPT_PointToFirstDPT: |
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210 | mov di, RAMVARS_size |
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211 | test BYTE [cs:ROMVARS.wFlags], FLG_ROMVARS_FULLMODE |
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212 | jz SHORT .Return ; RAMVARS used (top of interrupt vectors) |
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213 | add di, BYTE FULLRAMVARS_size-RAMVARS_size ; FULLRAMVARS used (top of base memory) |
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214 | ALIGN JUMP_ALIGN |
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215 | .Return: |
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216 | ret |
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