source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Inc/BootVars.inc@ 600

Last change on this file since 600 was 600, checked in by Tomi Tilli, 6 years ago

Hotkeybar timer tick handler now keeps interrupts disabled and updates on every fourth call.

File size: 6.0 KB
Line 
1; Project name : XTIDE Universal BIOS
2; Description : Defines for BOOTVARS struct used by boot menu
3; and drive initialization.
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%ifndef BOOTVARS_INC
22%define BOOTVARS_INC
23
24
25; Temporary locations for system interrupt handlers. Stored during ROM initialization
26; and needed when we do full initialization and drive detection on INT 19h
27TEMPORARY_VECTOR_FOR_SYSTEM_INT13h EQU 32h ; Unused by BIOS (reserved for DOS)
28TEMPORARY_VECTOR_FOR_SYSTEM_INT19h EQU 33h ; Unused by BIOS (reserved for DOS)
29
30
31; Default drives
32DEFAULT_FLOPPY_DRIVE_LETTER EQU 'A'
33DEFAULT_HARD_DRIVE_LETTER EQU 'C'
34
35; Number of times to retry booting before accepting error
36BOOT_READ_RETRY_TIMES EQU 3
37
38
39%ifdef MODULE_HOTKEYS
40
41struc HOTKEYVARS
42 .fpPrevTimerHandler resb 4 ; Previous 1Ch timer hander
43 .wTimeWhenDisplayed resb 2 ; System time (ticks) when Hotkey bar was first displayed
44 .wFddAndHddLetters:
45 .bFddLetter resb 1 ; Floppy Drive letter hotkey (upper case)
46 .wHddLetterAndFlags:
47 .bHddLetter resb 1 ; Hard Drive letter hotkey (upper case). Must be after .bFddLetter!
48 .bFlags resb 1 ; Must be just after .bHddLetter! (dependency in Hotkeybar.asm)
49 .bScancode resb 1 ; Function hotkey scancode, must be just after .bFlags!
50endstruc
51
52%ifndef CHECK_FOR_UNUSED_ENTRYPOINTS
53%if HOTKEYVARS.bFddLetter+1 != HOTKEYVARS.bHddLetter || HOTKEYVARS.bHddLetter+1 != HOTKEYVARS.bFlags || HOTKEYVARS.bFlags+1 != HOTKEYVARS.bScancode
54%error "HOTKEYVARS: bytes need to come in the order .bFddLetter, then .bHddLetter, then .bFlags, then .bScancode"
55%endif
56%endif
57
58; Bit defines for HOTKEYVARS.bFlags
59FLG_HOTKEY_HD_FIRST EQU (1<<0) ; First try to boot from HDD, then FDD
60
61%endif ; MODULE_HOTKEYS
62
63
64; Pre-boot variables. These do not exist after successful boot to OS.
65; Segment is always 0000h, same as BDA segment
66struc BOOTVARS
67 resb 7C00h
68 .rgbAtaInfo: ; 7C00h, ATA Information for drive detection
69 .rgbBootSect resb 512 ; 7C00h, Boot sector
70 resb 256 ; Boot Menu stack
71 .rgbMnuStack:
72 .dwPostStack resb 4 ; POST stack pointer when entering INT 19h
73%ifdef MODULE_HOTKEYS
74 .hotkeyVars resb HOTKEYVARS_size ; Must be located just before DRVDETECTINFO structs
75%endif
76 .rgDrvDetectInfo: ; Array containing DRVDETECTINFO structs
77endstruc
78
79
80; MAX_HARD_DISK_NAME_LENGTH must be defined ahead of the DRVDETECTINFO structure to avoid problems with NASM
81MAX_HARD_DISK_NAME_LENGTH EQU 30 ; Bytes reserved for drive name
82
83struc DRVDETECTINFO
84 .StartOfDrvDetectInfo:
85 .szDrvName resb MAX_HARD_DISK_NAME_LENGTH
86 resb 2 ; Zero word (ensures string terminates)
87 .wInitErrorFlags resb 2 ; Errors during initialization
88
89 ; DRVDETECTINFO's size must be an even multiple of DPT's size
90 .EndOfDriveDetectInfo: resb LARGEST_DPT_SIZE - (.EndOfDriveDetectInfo % LARGEST_DPT_SIZE)
91endstruc
92
93DPT_DRVDETECTINFO_SIZE_MULTIPLIER EQU DRVDETECTINFO_size / LARGEST_DPT_SIZE
94
95%ifndef CHECK_FOR_UNUSED_ENTRYPOINTS
96%if MAX_HARD_DISK_NAME_LENGTH % 2 <> 0
97 %error "MAX_HARD_DISK_NAME_LENGTH needs to be a multiple of 2, memory is moved with word operations."
98%endif
99%endif
100
101
102;--------------------------------------------------------------------
103; Stores POST stack pointer to BOOTVARS.
104;
105; STORE_POST_STACK_POINTER
106; Parameters:
107; ES: BDA and Interrupt Vector segment (zero)
108; Returns:
109; Nothing
110; Corrupts registers:
111; Nothing
112;--------------------------------------------------------------------
113%macro STORE_POST_STACK_POINTER 0
114 mov [es:BOOTVARS.dwPostStack], sp
115 mov [es:BOOTVARS.dwPostStack+2], ss
116%endmacro
117
118
119;--------------------------------------------------------------------
120; Initializes stack for boot menu usage.
121; POST stack is not large enough when DPTs are stored to 30:0h.
122;
123; Note regarding LOAD_BDA_SEGMENT_TO: If you force the use of SP
124; then you also have to unconditionally enable the CLI/STI pair.
125; The reason for this is that only some buggy 808x CPU:s need the
126; CLI/STI instruction pair when changing stacks. Other CPU:s disable
127; interrupts automatically when SS is modified for the duration of
128; the immediately following instruction to give time to change SP.
129;
130; SWITCH_TO_BOOT_MENU_STACK
131; Parameters:
132; Nothing
133; Returns:
134; SS:SP: Pointer to top of Boot Menu stack
135; Corrupts registers:
136; Nothing
137;--------------------------------------------------------------------
138%macro SWITCH_TO_BOOT_MENU_STACK 0
139%ifndef USE_186
140 cli ; Disable interrupts
141%endif
142 LOAD_BDA_SEGMENT_TO ss, sp
143 mov sp, BOOTVARS.rgbMnuStack ; Load offset to stack
144%ifndef USE_186
145 sti ; Enable interrupts
146%endif
147%endmacro
148
149
150;--------------------------------------------------------------------
151; Restores SS and SP to initial boot loader values.
152;
153; Note! Must return with AX=0 and CF preserved.
154; See Int19hMenu_JumpToBootSector_or_RomBoot.
155;
156; SWITCH_BACK_TO_POST_STACK
157; Parameters:
158; AX: BDA and Interrupt Vector segment (zero)
159; Returns:
160; SS:SP: Ptr to POST stack
161; Corrupts registers:
162; Nothing (not even FLAGS)
163;--------------------------------------------------------------------
164%macro SWITCH_BACK_TO_POST_STACK 0
165%ifndef USE_386
166 cli
167 mov ss, ax
168 mov sp, [ss:BOOTVARS.dwPostStack]
169 mov ss, [ss:BOOTVARS.dwPostStack+2]
170 sti
171%else
172 mov ss, ax
173 lss sp, [ss:BOOTVARS.dwPostStack]
174%endif
175%endmacro
176
177
178%endif ; BOOTVARS_INC
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