1 | ; Project name : XTIDE Universal BIOS
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2 | ; Description : Functions for accessings RAMVARS.
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3 |
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4 | ;
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5 | ; XTIDE Universal BIOS and Associated Tools
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6 | ; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team.
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7 | ;
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8 | ; This program is free software; you can redistribute it and/or modify
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9 | ; it under the terms of the GNU General Public License as published by
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10 | ; the Free Software Foundation; either version 2 of the License, or
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11 | ; (at your option) any later version.
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12 | ;
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13 | ; This program is distributed in the hope that it will be useful,
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14 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of
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15 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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16 | ; GNU General Public License for more details.
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17 | ; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
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18 | ;
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19 |
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20 | ; Section containing code
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21 | SECTION .text
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22 |
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23 | ;--------------------------------------------------------------------
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24 | ; Initializes RAMVARS.
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25 | ; Drive detection can be started after this function returns.
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26 | ;
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27 | ; RamVars_Initialize
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28 | ; Parameters:
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29 | ; Nothing
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30 | ; Returns:
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31 | ; DS: RAMVARS segment
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32 | ; Corrupts registers:
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33 | ; AX, CX, DI
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34 | ;--------------------------------------------------------------------
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35 | RamVars_Initialize:
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36 | push es
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37 | ; Fall to .StealMemoryForRAMVARS
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38 |
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39 | ;--------------------------------------------------------------------
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40 | ; .StealMemoryForRAMVARS
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41 | ; Parameters:
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42 | ; Nothing
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43 | ; Returns:
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44 | ; DS: RAMVARS segment
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45 | ; Corrupts registers:
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46 | ; AX, CL
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47 | ;--------------------------------------------------------------------
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48 | .StealMemoryForRAMVARS:
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49 | %ifndef USE_AT
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50 | mov ax, LITE_MODE_RAMVARS_SEGMENT
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51 | test BYTE [cs:ROMVARS.wFlags], FLG_ROMVARS_FULLMODE
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52 | jz SHORT .InitializeRamvars ; No need to steal RAM
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53 | %endif
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54 |
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55 | LOAD_BDA_SEGMENT_TO ds, ax, ! ; Zero AX
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56 | mov al, [cs:ROMVARS.bStealSize]
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57 | sub [BDA.wBaseMem], ax
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58 | mov ax, [BDA.wBaseMem]
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59 | %ifdef USE_186
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60 | shl ax, 6 ; Segment to first stolen kB (*=40h)
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61 | %else
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62 | mov cl, 6
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63 | shl ax, cl
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64 | %endif
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65 | ; Fall to .InitializeRamvars
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66 |
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67 | ;--------------------------------------------------------------------
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68 | ; .InitializeRamvars
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69 | ; Parameters:
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70 | ; AX: RAMVARS segment
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71 | ; Returns:
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72 | ; DS: RAMVARS segment
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73 | ; Corrupts registers:
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74 | ; AX, CX, DI, ES
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75 | ;--------------------------------------------------------------------
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76 | .InitializeRamvars:
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77 | mov ds, ax
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78 | mov es, ax
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79 | mov cx, RAMVARS_size
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80 | xor di, di
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81 | call Memory_ZeroESDIwithSizeInCX
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82 | mov WORD [RAMVARS.wDrvDetectSignature], RAMVARS_DRV_DETECT_SIGNATURE
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83 | mov WORD [RAMVARS.wSignature], RAMVARS_RAM_SIGNATURE
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84 | %ifdef MODULE_DRIVEXLATE
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85 | call DriveXlate_Reset
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86 | %endif
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87 |
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88 | pop es
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89 | ret
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90 |
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91 | ;--------------------------------------------------------------------
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92 | ; Returns segment to RAMVARS.
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93 | ; RAMVARS might be located at the top of interrupt vectors (0030:0000h)
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94 | ; or at the top of system base RAM.
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95 | ;
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96 | ; RamVars_GetSegmentToDS
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97 | ; Parameters:
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98 | ; Nothing
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99 | ; Returns:
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100 | ; DS: RAMVARS segment
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101 | ; Corrupts registers:
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102 | ; DI
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103 | ;--------------------------------------------------------------------
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104 | ALIGN JUMP_ALIGN
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105 | RamVars_GetSegmentToDS:
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106 |
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107 | %ifndef USE_AT ; Always in Full Mode for AT builds
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108 | test BYTE [cs:ROMVARS.wFlags], FLG_ROMVARS_FULLMODE
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109 | jnz SHORT .GetStolenSegmentToDS
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110 | %ifndef USE_186
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111 | mov di, LITE_MODE_RAMVARS_SEGMENT
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112 | mov ds, di
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113 | %else
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114 | push LITE_MODE_RAMVARS_SEGMENT
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115 | pop ds
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116 | %endif
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117 | ret
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118 | %endif
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119 |
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120 | ALIGN JUMP_ALIGN
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121 | .GetStolenSegmentToDS:
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122 | LOAD_BDA_SEGMENT_TO ds, di
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123 | mov di, [BDA.wBaseMem] ; Load available base memory size in kB
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124 | eSHL_IM di, 6 ; Segment to first stolen kB (*=40h)
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125 | ALIGN JUMP_ALIGN
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126 | .LoopStolenKBs:
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127 | mov ds, di ; EBDA segment to DS
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128 | add di, BYTE 64 ; DI to next stolen kB
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129 | cmp WORD [RAMVARS.wSignature], RAMVARS_RAM_SIGNATURE
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130 | jne SHORT .LoopStolenKBs ; Loop until sign found (always found eventually)
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131 | ret
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132 |
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133 |
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134 | ;--------------------------------------------------------------------
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135 | ; RamVars_GetHardDiskCountFromBDAtoAX
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136 | ; Parameters:
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137 | ; DS: RAMVARS segment
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138 | ; Returns:
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139 | ; AX: Total hard disk count
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140 | ; Corrupts registers:
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141 | ; BX
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142 | ;--------------------------------------------------------------------
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143 | %ifdef MODULE_BOOT_MENU
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144 | RamVars_GetHardDiskCountFromBDAtoAX:
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145 | call RamVars_GetCountOfKnownDrivesToAX
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146 | push ds
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147 | LOAD_BDA_SEGMENT_TO ds, bx
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148 | mov bl, [BDA.bHDCount]
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149 | MAX_U al, bl
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150 | pop ds
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151 | ret
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152 | %endif
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153 |
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154 |
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155 | ;--------------------------------------------------------------------
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156 | ; RamVars_GetCountOfKnownDrivesToAX
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157 | ; Parameters:
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158 | ; DS: RAMVARS segment
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159 | ; Returns:
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160 | ; AX: Total hard disk count
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161 | ; Corrupts registers:
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162 | ; None
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163 | ;--------------------------------------------------------------------
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164 | ALIGN JUMP_ALIGN
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165 | RamVars_GetCountOfKnownDrivesToAX:
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166 | mov ax, [RAMVARS.wFirstDrvAndCount]
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167 | add al, ah
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168 | and ax, BYTE 7fh
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169 | ret
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170 |
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171 | ;--------------------------------------------------------------------
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172 | ; RamVars_GetIdeControllerCountToCX
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173 | ; Parameters:
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174 | ; Nothing
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175 | ; Returns:
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176 | ; CX: Number of IDE controllers to handle
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177 | ; Corrupts registers:
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178 | ; Nothing
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179 | ;--------------------------------------------------------------------
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180 | ALIGN JUMP_ALIGN
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181 | RamVars_GetIdeControllerCountToCX:
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182 | eMOVZX cx, [cs:ROMVARS.bIdeCnt]
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183 | ret
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184 |
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185 |
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186 | %ifdef MODULE_SERIAL_FLOPPY
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187 | ;--------------------------------------------------------------------
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188 | ; RamVars_UnpackFlopCntAndFirstToAL
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189 | ; Parameters:
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190 | ; DS: RAMVARS segment
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191 | ; Returns:
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192 | ; AL: First floppy drive number supported
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193 | ; CF: Number of floppy drives supported (clear = 1, set = 2)
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194 | ; SF: Emulating drives (clear = yes, set = no)
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195 | ; Corrupts registers:
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196 | ; Nothing
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197 | ;--------------------------------------------------------------------
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198 | ALIGN JUMP_ALIGN
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199 | RamVars_UnpackFlopCntAndFirstToAL:
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200 | mov al, [RAMVARS.xlateVars+XLATEVARS.bFlopCntAndFirst]
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201 | sar al, 1
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202 | ret
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203 | %endif
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