| 1 | ; Project name : XTIDE Universal BIOS
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| 2 | ; Description : Functions for swapping drive letters.
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| 3 |
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| 4 | ; Section containing code
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| 5 | SECTION .text
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| 6 |
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| 7 | ;--------------------------------------------------------------------
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| 8 | ; Translates drive number when entering INT 13h.
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| 9 | ;
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| 10 | ; DriveXlate_WhenEnteringInt13h
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| 11 | ; Parameters:
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| 12 | ; DL: Drive number to be possibly translated
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| 13 | ; DS: RAMVARS segment
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| 14 | ; Returns:
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| 15 | ; DL: Translated drive number
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| 16 | ; Corrupts registers:
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| 17 | ; DI
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| 18 | ;--------------------------------------------------------------------
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| 19 | ALIGN JUMP_ALIGN
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| 20 | DriveXlate_WhenEnteringInt13h:
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| 21 | inc BYTE [RAMVARS.xlateVars+XLATEVARS.bRecurCnt]
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| 22 | cmp BYTE [RAMVARS.xlateVars+XLATEVARS.bRecurCnt], 1
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| 23 | je SHORT DriveXlate_ToOrBack
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| 24 | ret
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| 25 |
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| 26 |
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| 27 | ;--------------------------------------------------------------------
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| 28 | ; DriveXlate_WhenLeavingInt13hWithReturnValueInDL
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| 29 | ; Parameters:
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| 30 | ; DS: RAMVARS segment
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| 31 | ; Returns:
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| 32 | ; Nothing
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| 33 | ; Corrupts registers:
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| 34 | ; DI
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| 35 | ;--------------------------------------------------------------------
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| 36 | ALIGN JUMP_ALIGN
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| 37 | DriveXlate_WhenLeavingInt13hWithReturnValueInDL:
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| 38 | dec BYTE [RAMVARS.xlateVars+XLATEVARS.bRecurCnt]
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| 39 | ret
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| 40 |
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| 41 | ;--------------------------------------------------------------------
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| 42 | ; Translates drive number when leaving INT 13h.
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| 43 | ;
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| 44 | ; DriveXlate_WhenLeavingInt13h
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| 45 | ; Parameters:
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| 46 | ; DL: Drive number to be possibly translated
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| 47 | ; DS: RAMVARS segment
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| 48 | ; Returns:
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| 49 | ; DL: Translated drive number
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| 50 | ; Corrupts registers:
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| 51 | ; DI
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| 52 | ;--------------------------------------------------------------------
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| 53 | ALIGN JUMP_ALIGN
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| 54 | DriveXlate_WhenLeavingInt13h:
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| 55 | dec BYTE [RAMVARS.xlateVars+XLATEVARS.bRecurCnt]
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| 56 | jz SHORT DriveXlate_ToOrBack
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| 57 | ret
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| 58 |
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| 59 |
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| 60 | ;--------------------------------------------------------------------
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| 61 | ; Translates drive number to or back.
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| 62 | ;
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| 63 | ; DriveXlate_ToOrBack
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| 64 | ; Parameters:
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| 65 | ; DL: Drive number to be possibly translated
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| 66 | ; DS: RAMVARS segment
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| 67 | ; Returns:
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| 68 | ; DL: Translated drive number
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| 69 | ; Corrupts registers:
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| 70 | ; DI
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| 71 | ;--------------------------------------------------------------------
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| 72 | ALIGN JUMP_ALIGN
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| 73 | DriveXlate_ToOrBack:
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| 74 | test BYTE [cs:ROMVARS.wFlags], FLG_ROMVARS_DRVXLAT
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| 75 | jz SHORT .Return ; Return if translation disabled
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| 76 | xchg di, ax ; Backup AX
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| 77 | call DriveXlate_SwapFloppyDriveOrHardDisk
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| 78 | xchg ax, di
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| 79 | .Return:
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| 80 | ret
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| 81 |
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| 82 |
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| 83 | ;--------------------------------------------------------------------
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| 84 | ; Swaps Floppy Drive or Hard Disk number.
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| 85 | ;
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| 86 | ; DriveXlate_SwapFloppyDriveOrHardDisk
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| 87 | ; Parameters:
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| 88 | ; DL: Drive number to be possibly swapped
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| 89 | ; DS: RAMVARS segment
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| 90 | ; Returns:
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| 91 | ; DL: Translated drive number
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| 92 | ; Corrupts registers:
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| 93 | ; AX
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| 94 | ;--------------------------------------------------------------------
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| 95 | ALIGN JUMP_ALIGN
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| 96 | DriveXlate_SwapFloppyDriveOrHardDisk:
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| 97 | test dl, 80h ; Hard disk?
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| 98 | jnz SHORT .SwapHardDisk ; If so, jump to swap
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| 99 | ; Fall to .SwapFloppyDrive
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| 100 |
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| 101 | ;--------------------------------------------------------------------
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| 102 | ; .SwapFloppyDrive
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| 103 | ; Parameters:
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| 104 | ; DL: Drive number to be possibly swapped
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| 105 | ; DS: RAMVARS segment
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| 106 | ; Returns:
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| 107 | ; DL: Translated drive number
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| 108 | ; Corrupts registers:
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| 109 | ; AX
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| 110 | ;--------------------------------------------------------------------
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| 111 | .SwapFloppyDrive:
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| 112 | eMOVZX ax, BYTE [RAMVARS.xlateVars+XLATEVARS.bFDSwap]
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| 113 | jmp SHORT SwapDrive
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| 114 |
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| 115 | ;--------------------------------------------------------------------
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| 116 | ; .SwapHardDisk
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| 117 | ; Parameters:
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| 118 | ; DL: Drive number to be possibly swapped
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| 119 | ; DS: RAMVARS segment
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| 120 | ; Returns:
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| 121 | ; DL: Translated drive number
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| 122 | ; Corrupts registers:
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| 123 | ; AX
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| 124 | ;--------------------------------------------------------------------
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| 125 | ALIGN JUMP_ALIGN
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| 126 | .SwapHardDisk:
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| 127 | mov ah, 80h
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| 128 | mov al, BYTE [RAMVARS.xlateVars+XLATEVARS.bHDSwap]
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| 129 | ; Fall to SwapDrive
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| 130 |
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| 131 | ;--------------------------------------------------------------------
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| 132 | ; SwapDrive
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| 133 | ; Parameters:
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| 134 | ; AL: Drive number to swap to 00h/80h
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| 135 | ; AH: 00h/80h to be swapped to stored drive number
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| 136 | ; DL: Drive number to be possibly swapped
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| 137 | ; Returns:
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| 138 | ; DL: Translated drive number
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| 139 | ; Corrupts registers:
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| 140 | ; Nothing
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| 141 | ;--------------------------------------------------------------------
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| 142 | SwapDrive:
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| 143 | cmp ah, dl ; Swap DL from 00h/80h to xxh?
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| 144 | je SHORT .SwapToXXhInAL
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| 145 | cmp al, dl ; Swap DL from xxh to 00h/80h?
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| 146 | je SHORT .SwapTo00hOr80hInAH
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| 147 | ret
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| 148 | ALIGN JUMP_ALIGN
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| 149 | .SwapTo00hOr80hInAH:
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| 150 | mov dl, ah
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| 151 | ret
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| 152 | ALIGN JUMP_ALIGN
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| 153 | .SwapToXXhInAL:
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| 154 | mov dl, al
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| 155 | ret
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| 156 |
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| 157 |
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| 158 | ;--------------------------------------------------------------------
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| 159 | ; Resets drive swapping variables to defaults (no swapping).
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| 160 | ;
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| 161 | ; DriveXlate_Reset
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| 162 | ; Parameters:
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| 163 | ; DS: RAMVARS segment
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| 164 | ; Returns:
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| 165 | ; Nothing
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| 166 | ; Corrupts registers:
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| 167 | ; AX
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| 168 | ;--------------------------------------------------------------------
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| 169 | ALIGN JUMP_ALIGN
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| 170 | DriveXlate_Reset:
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| 171 | mov WORD [RAMVARS.xlateVars], 8000h ; .bFDSwap and .bHDSwap
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| 172 | mov BYTE [RAMVARS.xlateVars+XLATEVARS.bRecurCnt], 0
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| 173 | ret
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| 174 |
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| 175 |
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| 176 | ;--------------------------------------------------------------------
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| 177 | ; Stores drive to be swapped.
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| 178 | ;
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| 179 | ; DriveXlate_SetDriveToSwap
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| 180 | ; Parameters:
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| 181 | ; DL: Drive to swap to 00h or 80h
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| 182 | ; DS: RAMVARS segment
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| 183 | ; Returns:
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| 184 | ; Nothing
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| 185 | ; Corrupts registers:
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| 186 | ; Nothing
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| 187 | ;--------------------------------------------------------------------
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| 188 | ALIGN JUMP_ALIGN
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| 189 | DriveXlate_SetDriveToSwap:
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| 190 | test dl, 80h ; Floppy drive?
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| 191 | jnz SHORT .SetHardDiskToSwap
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| 192 | .SetFloppyDriveToSwap:
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| 193 | mov [RAMVARS.xlateVars+XLATEVARS.bFDSwap], dl
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| 194 | ret
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| 195 | ALIGN JUMP_ALIGN
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| 196 | .SetHardDiskToSwap:
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| 197 | mov [RAMVARS.xlateVars+XLATEVARS.bHDSwap], dl
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| 198 | ret
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| 199 |
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| 200 |
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| 201 | ;--------------------------------------------------------------------
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| 202 | ; Checks if INT 13h function returns some value in DL
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| 203 | ; (other than the drive number that was also parameter).
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| 204 | ;
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| 205 | ; DriveXlate_DoesFunctionReturnSomethingInDL
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| 206 | ; Parameters:
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| 207 | ; AH: INT 13h BIOS Function
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| 208 | ; DL: Drive number
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| 209 | ; Returns:
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| 210 | ; CF: Set if something is returned in DL
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| 211 | ; Cleared if only drive number parameter is returned in DL
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| 212 | ; Corrupts registers:
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| 213 | ; Nothing
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| 214 | ;--------------------------------------------------------------------
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| 215 | ALIGN JUMP_ALIGN
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| 216 | DriveXlate_DoesFunctionReturnSomethingInDL:
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| 217 | cmp ah, 08h ; AH=08h, Read Disk Drive Parameters?
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| 218 | je SHORT DriveXlate_FunctionReturnsSomethingInDL
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| 219 | test dl, 80h
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| 220 | jz SHORT DriveXlate_DoesFloppyFunctionReturnSomethingInDL
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| 221 | ; Fall to DriveXlate_DoesHardDiskFunctionReturnSomethingInDL
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| 222 |
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| 223 | ;--------------------------------------------------------------------
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| 224 | ; Checks if INT 13h hard disk or floppy drive function returns some
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| 225 | ; value in DL other than the drive number that was also parameter).
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| 226 | ; Some functions return different values for hard disks and floppy drives.
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| 227 | ;
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| 228 | ; DriveXlate_DoesHardDiskFunctionReturnSomethingInDL
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| 229 | ; DriveXlate_DoesFloppyFunctionReturnSomethingInDL
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| 230 | ; Parameters:
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| 231 | ; AH: INT 13h BIOS Function
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| 232 | ; DL: Hard Disk number
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| 233 | ; Returns:
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| 234 | ; CF: Set if something is returned in DL
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| 235 | ; Cleared if only drive number parameter is returned in DL
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| 236 | ; Corrupts registers:
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| 237 | ; Nothing
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| 238 | ;--------------------------------------------------------------------
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| 239 | ; ALIGN JUMP_ALIGN
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| 240 | DriveXlate_DoesHardDiskFunctionReturnSomethingInDL:
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| 241 | cmp ah, 15h ; AH=15h, Read Disk Drive Size?
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| 242 | je SHORT DriveXlate_FunctionReturnsSomethingInDL
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| 243 | DriveXlate_DoesFloppyFunctionReturnSomethingInDL:
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| 244 | clc
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| 245 | ret
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| 246 |
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| 247 | ALIGN JUMP_ALIGN
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| 248 | DriveXlate_FunctionReturnsSomethingInDL:
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| 249 | stc
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| 250 | ret
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