1 | ; Project name : XTIDE Universal BIOS
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2 | ; Description : Various floppy drive related functions that
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3 | ; Boot Menu uses.
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4 |
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5 | ;
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6 | ; XTIDE Universal BIOS and Associated Tools
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7 | ; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team.
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8 | ;
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9 | ; This program is free software; you can redistribute it and/or modify
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10 | ; it under the terms of the GNU General Public License as published by
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11 | ; the Free Software Foundation; either version 2 of the License, or
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12 | ; (at your option) any later version.
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13 | ;
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14 | ; This program is distributed in the hope that it will be useful,
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15 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of
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16 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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17 | ; GNU General Public License for more details.
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18 | ; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
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19 | ;
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20 |
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21 | ; Section containing code
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22 | SECTION .text
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23 |
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24 | ;--------------------------------------------------------------------
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25 | ; Checks is floppy drive handler installed to interrupt vector 40h.
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26 | ;
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27 | ; FloppyDrive_IsInt40hInstalled
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28 | ; Parameters:
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29 | ; ES: BDA and Interrupt Vector segment (zero)
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30 | ; Returns:
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31 | ; CF: Set if INT 40h is installed
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32 | ; Cleared if INT 40h is not installed
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33 | ; Corrupts registers:
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34 | ; BX, CX, DI
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35 | ;--------------------------------------------------------------------
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36 | FloppyDrive_IsInt40hInstalled:
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37 | %ifdef USE_AT
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38 | push es
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39 | push dx
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40 | push ax
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41 |
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42 | call LoadInt40hVerifyParameters
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43 | int BIOS_DISK_INTERRUPT_13h
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44 | jc SHORT .Int40hIsInstalled ; Maybe there are not any floppy drives at all
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45 | push es ; Drive Parameter Table segment
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46 | push di ; Drive Parameter Table offset
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47 |
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48 | call LoadInt40hVerifyParameters
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49 | int BIOS_DISKETTE_INTERRUPT_40h
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50 |
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51 | pop dx
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52 | pop cx
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53 | cmp dx, di ; Difference in offsets?
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54 | jne SHORT .Int40hNotInstalled
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55 | mov dx, es
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56 | cmp cx, dx ; Difference in segments?
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57 | je SHORT .Int40hIsInstalled
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58 | .Int40hNotInstalled:
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59 | stc
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60 | .Int40hIsInstalled:
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61 | pop ax
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62 | pop dx
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63 | pop es
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64 |
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65 | %else ; if XT build
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66 | cmp BYTE [es:BIOS_DISKETTE_INTERRUPT_40h*4+3], 0C0h ; Any ROM segment? (set CF if not)
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67 | %endif ; USE_AT
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68 | cmc
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69 | ret
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70 |
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71 | ;--------------------------------------------------------------------
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72 | ; LoadInt40hVerifyParameters
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73 | ; Parameters:
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74 | ; Nothing
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75 | ; Returns:
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76 | ; AH: 08h (Get Drive Parameters)
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77 | ; DL: 00h (floppy drive)
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78 | ; ES:DI: 0:0h (to guard against BIOS bugs)
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79 | ; Corrupts registers:
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80 | ; DH
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81 | ;--------------------------------------------------------------------
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82 | %ifdef USE_AT
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83 | LoadInt40hVerifyParameters:
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84 | mov ah, GET_DRIVE_PARAMETERS
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85 | cwd ; Floppy drive 0
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86 | mov di, dx
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87 | mov es, dx ; ES:DI = 0000:0000h to guard against BIOS bugs
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88 | ret
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89 | %endif
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90 |
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91 |
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92 | ;--------------------------------------------------------------------
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93 | ; Returns floppy drive type.
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94 | ; PC/XT system do not support AH=08h but FLOPPY_TYPE_525_OR_35_DD
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95 | ; is still returned for them.
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96 | ;
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97 | ; FloppyDrive_GetType
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98 | ; Parameters:
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99 | ; DL: Floppy Drive number
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100 | ; Returns:
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101 | ; BX: Floppy Drive Type:
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102 | ; FLOPPY_TYPE_525_OR_35_DD
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103 | ; FLOPPY_TYPE_525_DD
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104 | ; FLOPPY_TYPE_525_HD
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105 | ; FLOPPY_TYPE_35_DD
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106 | ; FLOPPY_TYPE_35_HD
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107 | ; FLOPPY_TYPE_35_ED
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108 | ; CF: Set if AH=08h not supported (XT systems) or error
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109 | ; Cleared if type read correctly (AT systems)
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110 | ; Corrupts registers:
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111 | ; AX, CX, DX, DI, ES
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112 | ;--------------------------------------------------------------------
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113 | %ifdef MODULE_BOOT_MENU
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114 | FloppyDrive_GetType:
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115 | mov ah, GET_DRIVE_PARAMETERS
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116 | xor bx, bx ; FLOPPY_TYPE_525_OR_35_DD when function not supported
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117 | int BIOS_DISKETTE_INTERRUPT_40h
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118 | ret
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119 | %endif
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120 |
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121 |
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122 | ;--------------------------------------------------------------------
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123 | ; Returns number of Floppy Drives in system.
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124 | ;
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125 | ; FloppyDrive_GetCountToAX
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126 | ; Parameters:
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127 | ; DS: RAMVARS Segment
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128 | ; Returns:
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129 | ; AX: Number of Floppy Drives
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130 | ;--------------------------------------------------------------------
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131 | FloppyDrive_GetCountToAX:
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132 | %ifdef MODULE_SERIAL_FLOPPY
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133 | call RamVars_UnpackFlopCntAndFirstToAL
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134 | js .UseBIOSorBDA ; We didn't add in any drives, counts here are not valid
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135 |
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136 | adc al, 1 ; adds in the drive count bit, and adds 1 for count vs. 0-index,
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137 | jmp .FinishCalc ; need to clear AH on the way out, and add in minimum drive numbers
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138 |
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139 | .UseBIOSorBDA:
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140 | %endif
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141 | call FloppyDrive_GetCountFromBIOS_or_BDA
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142 |
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143 | .FinishCalc:
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144 | mov ah, [cs:ROMVARS.bMinFddCnt]
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145 | MAX_U al, ah
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146 | cbw
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147 |
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148 | ret
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149 |
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150 |
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151 | ;--------------------------------------------------------------------
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152 | ; FloppyDrive_GetCountFromBIOS_or_BDA
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153 | ; Parameters:
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154 | ; Nothing
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155 | ; Returns:
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156 | ; AL: Number of Floppy Drives
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157 | ; CF: Cleared if successful
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158 | ; Set if BIOS function not supported
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159 | ; Corrupts registers:
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160 | ; AH
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161 | ;--------------------------------------------------------------------
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162 | FloppyDrive_GetCountFromBIOS_or_BDA:
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163 | %ifdef USE_AT
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164 | ; Reads Floppy Drive Count from BIOS.
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165 | ; Does not work on most XT systems. Call .GetCountFromBDA
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166 | ; if this function fails.
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167 |
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168 | push es
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169 | push di
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170 | push bx
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171 | push cx
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172 | push dx
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173 |
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174 | mov ah, GET_DRIVE_PARAMETERS
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175 | cwd ; Floppy Drive 00h
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176 | int BIOS_DISKETTE_INTERRUPT_40h
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177 | xchg ax, dx ; Number of Floppy Drives to AL
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178 |
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179 | pop dx
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180 | pop cx
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181 | pop bx
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182 | pop di
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183 | pop es
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184 |
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185 | %else ; ifndef USE_AT
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186 | ; Reads Floppy Drive Count (0...4) from BIOS Data Area.
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187 | ; This function should be used only if .GetCountFromBIOS fails.
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188 |
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189 | push ds
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190 | LOAD_BDA_SEGMENT_TO ds, ax
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191 | mov al, [BDA.wEquipment] ; Load Equipment WORD low byte
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192 | and al, 0C1h ; Leave bits 7..6 and 0
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193 | eAAM 64
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194 | add al, ah ; AL = Floppy Drive count
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195 | pop ds
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196 | %endif ; USE_AT
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197 |
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198 | ret
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