source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13hBiosInit.asm@ 586

Last change on this file since 586 was 566, checked in by krille_n_@…, 11 years ago

Changes to XTIDE Universal BIOS:

  • Fixed a very old bug (from r150) in IdeError.asm where GetBiosErrorCodeToAHfromStatusAndErrorRegistersInAX would return RET_HD_SEEK_FAIL instead of RET_HD_STATUSERR.
  • Optimizations and other fixes.
File size: 2.2 KB
Line 
1; Project name : XTIDE Universal BIOS
2; Description : Int 13h handler that is used to initialize
3; XTIDE Universal BIOS when our INT 19h was not called.
4
5;
6; XTIDE Universal BIOS and Associated Tools
7; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team.
8;
9; This program is free software; you can redistribute it and/or modify
10; it under the terms of the GNU General Public License as published by
11; the Free Software Foundation; either version 2 of the License, or
12; (at your option) any later version.
13;
14; This program is distributed in the hope that it will be useful,
15; but WITHOUT ANY WARRANTY; without even the implied warranty of
16; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17; GNU General Public License for more details.
18; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
19;
20
21; Section containing code
22SECTION .text
23
24TEMPORARY_VECTOR_FOR_SYSTEM_INT13h EQU 32h ; Unused by BIOS
25
26
27;--------------------------------------------------------------------
28; Int 13h software interrupt handler.
29; This handler captures boot sector read from foreign drive when our
30; INT 19h is not called. This way we can force XTIDE Universal BIOS
31; initialization even without INT 19h being called.
32;
33; Int13hBiosInit_Handler
34; Parameters:
35; AH: Bios function
36; READ_SECTORS_INTO_MEMORY will initialize XTIDE Universal BIOS
37;--------------------------------------------------------------------
38Int13hBiosInit_Handler:
39 ; Initialize XTIDE Universal BIOS only if Int13hBiosInit_Handler is still at
40 ; vector 13h. Otherwise some other BIOS has hooked us and our very late
41 ; initialization is not possible.
42 push ds
43 push ax
44 LOAD_BDA_SEGMENT_TO ds, ax
45 pop ax
46 cmp WORD [BIOS_DISK_INTERRUPT_13h*4], Int13hBiosInit_Handler
47 pop ds
48 jne SHORT .VeryLateInitFailed ; XTIDE Universal BIOS does not work
49
50 ; Ignore all but read command (assumed to read boot sector)
51 cmp ah, READ_SECTORS_INTO_MEMORY
52 je SHORT Int19h_BootLoaderHandler
53
54 ; Call system INT 13h since not trying to read boot sector
55 int TEMPORARY_VECTOR_FOR_SYSTEM_INT13h
56 retf 2
57
58.VeryLateInitFailed:
59 mov ah, RET_HD_INVALID
60 stc
61 retf 2
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