source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Initialization/DriveXlate.asm@ 391

Last change on this file since 391 was 376, checked in by gregli@…, 13 years ago

WIDE checkin... Added copyright and license information to sorce files, as per the GPL instructions for usage.

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1; Project name : XTIDE Universal BIOS
2; Description : Functions for swapping drive letters.
3
4;
5; XTIDE Universal BIOS and Associated Tools
6; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2012 by XTIDE Universal BIOS Team.
7;
8; This program is free software; you can redistribute it and/or modify
9; it under the terms of the GNU General Public License as published by
10; the Free Software Foundation; either version 2 of the License, or
11; (at your option) any later version.
12;
13; This program is distributed in the hope that it will be useful,
14; but WITHOUT ANY WARRANTY; without even the implied warranty of
15; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16; GNU General Public License for more details.
17; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
18;
19
20; Section containing code
21SECTION .text
22
23;--------------------------------------------------------------------
24; DriveXlate_ToOrBack
25; Parameters:
26; DL: Drive number to be possibly translated
27; DS: RAMVARS segment
28; Returns:
29; DL: Translated drive number
30; Corrupts registers:
31; DI
32;--------------------------------------------------------------------
33ALIGN JUMP_ALIGN
34DriveXlate_ToOrBack:
35 test BYTE [cs:ROMVARS.wFlags], FLG_ROMVARS_DRVXLAT
36 jz SHORT .Return ; Return if translation disabled
37 xchg di, ax ; Backup AX
38
39 mov ah, 80h ; Assume hard disk
40 mov al, [RAMVARS.xlateVars+XLATEVARS.bHDSwap]
41 test dl, ah ; Hard disk?
42 jnz SHORT .SwapDrive ; If so, jump to swap
43 mov al, [RAMVARS.xlateVars+XLATEVARS.bFDSwap]
44 cbw
45
46ALIGN JUMP_ALIGN
47.SwapDrive:
48 cmp ah, dl ; Swap DL from 00h/80h to xxh?
49 je SHORT .SwapToXXhInAL
50 cmp al, dl ; Swap DL from xxh to 00h/80h?
51 jne SHORT .RestoreAXandReturn
52 mov al, ah
53ALIGN JUMP_ALIGN
54.SwapToXXhInAL:
55 mov dl, al
56ALIGN JUMP_ALIGN
57.RestoreAXandReturn:
58 xchg ax, di ; Restore AX
59ALIGN JUMP_ALIGN, ret
60.Return:
61 ret
62
63
64;--------------------------------------------------------------------
65; Resets drive swapping variables to defaults (no swapping).
66;
67; DriveXlate_Reset
68; Parameters:
69; DS: RAMVARS segment
70; Returns:
71; Nothing
72; Corrupts registers:
73; Nothing
74;--------------------------------------------------------------------
75ALIGN JUMP_ALIGN
76DriveXlate_Reset:
77 mov WORD [RAMVARS.xlateVars+XLATEVARS.wFDandHDswap], 8000h
78 ret
79
80
81;--------------------------------------------------------------------
82; Stores drive to be swapped.
83;
84; DriveXlate_SetDriveToSwap
85; Parameters:
86; DL: Drive to swap to 00h or 80h
87; DS: RAMVARS segment
88; Returns:
89; Nothing
90; Corrupts registers:
91; Nothing
92;--------------------------------------------------------------------
93ALIGN JUMP_ALIGN
94DriveXlate_SetDriveToSwap:
95 test dl, dl ; Floppy drive?
96 js SHORT .SetHardDiskToSwap
97.SetFloppyDriveToSwap:
98 mov [RAMVARS.xlateVars+XLATEVARS.bFDSwap], dl
99 ret
100ALIGN JUMP_ALIGN
101.SetHardDiskToSwap:
102 mov [RAMVARS.xlateVars+XLATEVARS.bHDSwap], dl
103 ret
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