| 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 | ; DriveXlate_ToOrBack
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| 9 | ; Parameters:
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| 10 | ; DL: Drive number to be possibly translated
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| 11 | ; DS: RAMVARS segment
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| 12 | ; Returns:
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| 13 | ; DL: Translated drive number
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| 14 | ; Corrupts registers:
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| 15 | ; DI
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| 16 | ;--------------------------------------------------------------------
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| 17 | ALIGN JUMP_ALIGN
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| 18 | DriveXlate_ToOrBack:
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| 19 | test BYTE [cs:ROMVARS.wFlags], FLG_ROMVARS_DRVXLAT
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| 20 | jz SHORT .Return ; Return if translation disabled
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| 21 | xchg di, ax ; Backup AX
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| 22 |
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| 23 | mov ah, 80h ; Assume hard disk
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| 24 | mov al, [RAMVARS.xlateVars+XLATEVARS.bHDSwap]
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| 25 | test dl, ah ; Hard disk?
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| 26 | jnz SHORT .SwapDrive ; If so, jump to swap
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| 27 | mov al, [RAMVARS.xlateVars+XLATEVARS.bFDSwap]
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| 28 | cbw
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| 29 |
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| 30 | ALIGN JUMP_ALIGN
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| 31 | .SwapDrive:
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| 32 | cmp ah, dl ; Swap DL from 00h/80h to xxh?
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| 33 | je SHORT .SwapToXXhInAL
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| 34 | cmp al, dl ; Swap DL from xxh to 00h/80h?
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| 35 | jne SHORT .RestoreAXandReturn
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| 36 | mov al, ah
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| 37 | ALIGN JUMP_ALIGN
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| 38 | .SwapToXXhInAL:
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| 39 | mov dl, al
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| 40 | ALIGN JUMP_ALIGN
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| 41 | .RestoreAXandReturn:
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| 42 | xchg ax, di ; Restore AX
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| 43 | ALIGN JUMP_ALIGN, ret
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| 44 | .Return:
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| 45 | ret
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| 46 |
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| 47 |
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| 48 | ;--------------------------------------------------------------------
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| 49 | ; Resets drive swapping variables to defaults (no swapping).
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| 50 | ;
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| 51 | ; DriveXlate_Reset
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| 52 | ; Parameters:
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| 53 | ; DS: RAMVARS segment
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| 54 | ; Returns:
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| 55 | ; Nothing
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| 56 | ; Corrupts registers:
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| 57 | ; Nothing
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| 58 | ;--------------------------------------------------------------------
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| 59 | ALIGN JUMP_ALIGN
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| 60 | DriveXlate_Reset:
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| 61 | mov WORD [RAMVARS.xlateVars+XLATEVARS.wFDandHDswap], 8000h
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| 62 | ret
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| 63 |
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| 64 |
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| 65 | ;--------------------------------------------------------------------
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| 66 | ; Stores drive to be swapped.
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| 67 | ;
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| 68 | ; DriveXlate_SetDriveToSwap
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| 69 | ; Parameters:
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| 70 | ; DL: Drive to swap to 00h or 80h
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| 71 | ; DS: RAMVARS segment
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| 72 | ; Returns:
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| 73 | ; Nothing
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| 74 | ; Corrupts registers:
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| 75 | ; Nothing
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| 76 | ;--------------------------------------------------------------------
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| 77 | ALIGN JUMP_ALIGN
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| 78 | DriveXlate_SetDriveToSwap:
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| 79 | test dl, dl ; Floppy drive?
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| 80 | js SHORT .SetHardDiskToSwap
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| 81 | .SetFloppyDriveToSwap:
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| 82 | mov [RAMVARS.xlateVars+XLATEVARS.bFDSwap], dl
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| 83 | ret
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| 84 | ALIGN JUMP_ALIGN
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| 85 | .SetHardDiskToSwap:
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| 86 | mov [RAMVARS.xlateVars+XLATEVARS.bHDSwap], dl
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| 87 | ret
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