[243] | 1 | ; Project name : XTIDE Universal BIOS
|
---|
| 2 | ; Description : Int 19h Handler (Boot Loader).
|
---|
| 3 |
|
---|
[376] | 4 | ;
|
---|
[505] | 5 | ; XTIDE Universal BIOS and Associated Tools
|
---|
[376] | 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.
|
---|
[505] | 12 | ;
|
---|
[376] | 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
|
---|
[505] | 16 | ; GNU General Public License for more details.
|
---|
[376] | 17 | ; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
|
---|
[505] | 18 | ;
|
---|
[376] | 19 |
|
---|
[243] | 20 | ; Section containing code
|
---|
| 21 | SECTION .text
|
---|
| 22 |
|
---|
| 23 | ;--------------------------------------------------------------------
|
---|
| 24 | ; Int19h_BootLoaderHandler
|
---|
| 25 | ; Parameters:
|
---|
| 26 | ; Nothing
|
---|
| 27 | ; Returns:
|
---|
| 28 | ; Never returns (loads operating system)
|
---|
| 29 | ;--------------------------------------------------------------------
|
---|
| 30 | Int19h_BootLoaderHandler:
|
---|
[414] | 31 | sti ; Enable interrupts
|
---|
| 32 | cld ; String instructions to increment pointers
|
---|
| 33 | LOAD_BDA_SEGMENT_TO es, ax ; Load BDA segment (zero) to ES
|
---|
[392] | 34 | ; Fall to .PrepareBootLoaderStack
|
---|
[243] | 35 |
|
---|
[392] | 36 |
|
---|
[243] | 37 | ;--------------------------------------------------------------------
|
---|
[392] | 38 | ; Drive detection and boot menu use lots of stack so it is
|
---|
| 39 | ; wise to relocate stack. Otherwise something important from
|
---|
| 40 | ; interrupt vectors are likely corrupted, likely our own DPTs if
|
---|
| 41 | ; they are located to 30:0h.
|
---|
| 42 | ;
|
---|
| 43 | ; .PrepareBootLoaderStack
|
---|
[243] | 44 | ; Parameters:
|
---|
| 45 | ; ES: BDA and interrupt vector segment (zero)
|
---|
| 46 | ; Returns:
|
---|
| 47 | ; Never returns (loads operating system)
|
---|
| 48 | ;--------------------------------------------------------------------
|
---|
[392] | 49 | .PrepareBootLoaderStack:
|
---|
[243] | 50 | STORE_POST_STACK_POINTER
|
---|
| 51 | SWITCH_TO_BOOT_MENU_STACK
|
---|
| 52 | ; Fall to .InitializeDisplay
|
---|
| 53 |
|
---|
[392] | 54 |
|
---|
[243] | 55 | ;--------------------------------------------------------------------
|
---|
| 56 | ; .InitializeDisplay
|
---|
| 57 | ; Parameters:
|
---|
[392] | 58 | ; ES: BDA and interrupt vector segment (zero)
|
---|
[243] | 59 | ; Returns:
|
---|
| 60 | ; Never returns (loads operating system)
|
---|
| 61 | ;--------------------------------------------------------------------
|
---|
| 62 | .InitializeDisplay:
|
---|
| 63 | ; Change display mode if necessary
|
---|
| 64 | mov ax, [cs:ROMVARS.wDisplayMode] ; AH 00h = Set Video Mode
|
---|
| 65 | cmp al, DEFAULT_TEXT_MODE
|
---|
| 66 | je SHORT .InitializeDisplayLibrary
|
---|
| 67 | int BIOS_VIDEO_INTERRUPT_10h
|
---|
| 68 | .InitializeDisplayLibrary:
|
---|
[392] | 69 | call DetectPrint_InitializeDisplayContext
|
---|
| 70 | ; Fall to .InitializeBiosAndDetectDrives
|
---|
[243] | 71 |
|
---|
[392] | 72 |
|
---|
[243] | 73 | ;--------------------------------------------------------------------
|
---|
[392] | 74 | ; .InitializeBiosAndDetectDrives
|
---|
[243] | 75 | ; Parameters:
|
---|
[392] | 76 | ; ES: BDA and interrupt vector segment (zero)
|
---|
[243] | 77 | ; Returns:
|
---|
[392] | 78 | ; DS: RAMVARS segment
|
---|
[243] | 79 | ;--------------------------------------------------------------------
|
---|
[413] | 80 | %ifdef MODULE_HOTKEYS
|
---|
| 81 | call TimerTicks_ReadFromBdaToAX
|
---|
| 82 | add ax, MIN_TIME_TO_DISPLAY_HOTKEY_BAR
|
---|
| 83 | mov [es:BOOTVARS.hotkeyVars+HOTKEYVARS.wTimeToClose], ax
|
---|
| 84 | %endif
|
---|
| 85 |
|
---|
| 86 | call Initialize_AndDetectDrives
|
---|
| 87 |
|
---|
| 88 | %ifdef MODULE_HOTKEYS
|
---|
| 89 | .WaitUntilTimeToCloseHotkeyBar:
|
---|
| 90 | call TimerTicks_ReadFromBdaToAX
|
---|
| 91 | cmp ax, [es:BOOTVARS.hotkeyVars+HOTKEYVARS.wTimeToClose]
|
---|
| 92 | jb SHORT .WaitUntilTimeToCloseHotkeyBar
|
---|
| 93 | %endif
|
---|
[392] | 94 | ; Fall to SelectDriveToBootFrom
|
---|
[243] | 95 |
|
---|
[392] | 96 |
|
---|
[243] | 97 | ;--------------------------------------------------------------------
|
---|
[392] | 98 | ; SelectDriveToBootFrom
|
---|
[243] | 99 | ; Parameters:
|
---|
| 100 | ; DS: RAMVARS segment
|
---|
[392] | 101 | ; ES: BDA and interrupt vector segment (zero)
|
---|
[243] | 102 | ; Returns:
|
---|
| 103 | ; Never returns (loads operating system)
|
---|
| 104 | ;--------------------------------------------------------------------
|
---|
[392] | 105 | SelectDriveToBootFrom:
|
---|
[492] | 106 |
|
---|
| 107 | ; The following macro could be easily inlined below. Why a macro? Depending on the combination
|
---|
| 108 | ; of MODULE_HOTKEYS or MODULE_BOOT_MENU, this code needs to either come before or after the
|
---|
[505] | 109 | ; call to the boot menu.
|
---|
[492] | 110 | ;
|
---|
| 111 | %macro TRY_TO_BOOT_DL_AND_DH_DRIVES 0
|
---|
| 112 | push dx ; it's OK if this is left on the stack, if we are
|
---|
[505] | 113 | ; successful, the following call does not return
|
---|
[492] | 114 | call TryToBootFromPrimaryOrSecondaryBootDevice_AndBoot
|
---|
| 115 | pop dx
|
---|
| 116 | mov dl, dh
|
---|
| 117 | call TryToBootFromPrimaryOrSecondaryBootDevice_AndBoot
|
---|
| 118 | %endmacro
|
---|
[505] | 119 |
|
---|
[395] | 120 | %ifdef MODULE_HOTKEYS
|
---|
[505] | 121 | call HotkeyBar_ScanHotkeysFromKeyBufferAndStoreToBootvars
|
---|
[492] | 122 | cmp al, ROM_BOOT_HOTKEY_SCANCODE
|
---|
[505] | 123 | je .RomBoot ; CF clear so ROM boot
|
---|
[392] | 124 | %ifdef MODULE_BOOT_MENU
|
---|
[492] | 125 | cmp al, BOOT_MENU_HOTKEY_SCANCODE
|
---|
[505] | 126 | je .BootMenu
|
---|
[392] | 127 | %endif
|
---|
[492] | 128 | call HotkeyBar_GetBootDriveNumbersToDX
|
---|
| 129 | .TryUsingHotKeysCode:
|
---|
| 130 | TRY_TO_BOOT_DL_AND_DH_DRIVES
|
---|
| 131 | ;; falls through to boot menu, if it is present. If not present, falls through to rom boot.
|
---|
[505] | 132 | %endif ; MODULE_HOTKEYS
|
---|
[392] | 133 |
|
---|
[492] | 134 | %ifdef MODULE_BOOT_MENU
|
---|
[505] | 135 | .BootMenu:
|
---|
[492] | 136 | call BootMenu_DisplayAndReturnDriveInDLRomBootClearCF
|
---|
[493] | 137 | jnc .RomBoot ; CF clear so ROM boot
|
---|
[392] | 138 |
|
---|
[492] | 139 | mov dh, dl ; Setup for secondary drive
|
---|
[505] | 140 | not dh ; Floppy goes to HD, or vice versa
|
---|
| 141 | and dh, 80h ; Go to first drive of the floppy or HD set
|
---|
[398] | 142 |
|
---|
[395] | 143 | %ifdef MODULE_HOTKEYS
|
---|
[492] | 144 | jmp .TryUsingHotKeysCode
|
---|
[395] | 145 | %else
|
---|
[505] | 146 | TRY_TO_BOOT_DL_AND_DH_DRIVES
|
---|
[492] | 147 | jmp .BootMenu
|
---|
[395] | 148 | %endif
|
---|
[505] | 149 | %endif ; MODULE_BOOT_MENU
|
---|
[392] | 150 |
|
---|
[505] | 151 | %ifndef MODULE_HOTKEYS OR MODULE_BOOT_MENU
|
---|
[492] | 152 | xor dl, dl ; Try to boot from Floppy Drive A
|
---|
| 153 | call TryToBootFromPrimaryOrSecondaryBootDevice_AndBoot
|
---|
| 154 | mov dl, 80h ; Try to boot from Hard Drive C
|
---|
| 155 | call TryToBootFromPrimaryOrSecondaryBootDevice_AndBoot
|
---|
[386] | 156 | %endif
|
---|
[243] | 157 |
|
---|
[493] | 158 | .RomBoot:
|
---|
| 159 | %ifdef MODULE_DRIVEXLATE
|
---|
| 160 | call DriveXlate_Reset ; Clean up any drive mappings before Rom Boot
|
---|
| 161 | %endif
|
---|
[505] | 162 | clc
|
---|
[493] | 163 | ;; fall through to JumpToBootSector_or_RomBoot
|
---|
[392] | 164 |
|
---|
[243] | 165 | ;--------------------------------------------------------------------
|
---|
[392] | 166 | ; JumpToBootSector_or_RomBoot
|
---|
[243] | 167 | ;
|
---|
| 168 | ; Switches back to the POST stack, clears the DS and ES registers,
|
---|
| 169 | ; and either jumps to the MBR (Master Boot Record) that was just read,
|
---|
| 170 | ; or calls the ROM's boot routine on interrupt 18.
|
---|
| 171 | ;
|
---|
| 172 | ; Parameters:
|
---|
| 173 | ; DL: Drive to boot from (translated, 00h or 80h)
|
---|
[505] | 174 | ; CF: Set for Boot Sector Boot
|
---|
[392] | 175 | ; Clear for ROM Boot
|
---|
[243] | 176 | ; ES:BX: (if CF set) Ptr to boot sector
|
---|
| 177 | ;
|
---|
| 178 | ; Returns:
|
---|
| 179 | ; Never returns
|
---|
| 180 | ;--------------------------------------------------------------------
|
---|
[392] | 181 | JumpToBootSector_or_RomBoot:
|
---|
[243] | 182 | mov cx, es ; Preserve MBR segment (can't push because of stack change)
|
---|
| 183 | mov ax, 0 ; NOTE: can't use XOR (LOAD_BDA_SEGMENT_TO) as it impacts CF
|
---|
| 184 | SWITCH_BACK_TO_POST_STACK
|
---|
| 185 |
|
---|
| 186 | ; clear segment registers before boot sector or rom call
|
---|
[505] | 187 | mov ds, ax
|
---|
[243] | 188 | mov es, ax
|
---|
| 189 | %ifdef USE_386
|
---|
| 190 | mov fs, ax
|
---|
| 191 | mov gs, ax
|
---|
| 192 | %endif
|
---|
| 193 | jnc SHORT .romboot
|
---|
| 194 |
|
---|
| 195 | ; jump to boot sector
|
---|
| 196 | push cx ; sgment address for MBR
|
---|
| 197 | push bx ; offset address for MBR
|
---|
| 198 | retf ; NOTE: DL is set to the drive number
|
---|
| 199 |
|
---|
| 200 | ; Boot by calling INT 18h (ROM Basic of ROM DOS)
|
---|
| 201 | .romboot:
|
---|
[505] | 202 | int BIOS_BOOT_FAILURE_INTERRUPT_18h ; Never returns
|
---|
[392] | 203 |
|
---|
| 204 |
|
---|
| 205 | ;--------------------------------------------------------------------
|
---|
[505] | 206 | ; TryToBootFromPrimaryOrSecondaryBootDevice_AndBoot
|
---|
[392] | 207 | ; Parameters
|
---|
| 208 | ; DL: Drive selected as boot device
|
---|
| 209 | ; DS: RAMVARS segment
|
---|
| 210 | ; ES: BDA and interrupt vector segment (zero)
|
---|
| 211 | ; Returns:
|
---|
| 212 | ; DL: Drive to boot from (translated, 00h or 80h)
|
---|
| 213 | ; CF: Set for Boot Sector Boot
|
---|
| 214 | ; Clear for ROM Boot
|
---|
| 215 | ; ES:BX: (if CF set) Ptr to boot sector
|
---|
| 216 | ; Corrupts registers:
|
---|
| 217 | ; AX, CX, DH, SI, DI, (DL if failed to read boot sector)
|
---|
| 218 | ;--------------------------------------------------------------------
|
---|
[492] | 219 | %ifndef MODULE_DRIVEXLATE
|
---|
| 220 | TryToBootFromPrimaryOrSecondaryBootDevice_AndBoot EQU BootSector_TryToLoadFromDriveDL_AndBoot
|
---|
[395] | 221 |
|
---|
| 222 | %else
|
---|
[492] | 223 | TryToBootFromPrimaryOrSecondaryBootDevice_AndBoot:
|
---|
[392] | 224 | call DriveXlate_SetDriveToSwap
|
---|
| 225 | call DriveXlate_ToOrBack
|
---|
[492] | 226 | ; fall through to TryToBoot_FallThroughTo_BootSector_TryToLoadFromDriveDL_AndBoot
|
---|
| 227 |
|
---|
| 228 | TryToBoot_FallThroughTo_BootSector_TryToLoadFromDriveDL_AndBoot:
|
---|
[505] | 229 | ; fall through to BootSector_TryToLoadFromDriveDL_AndBoot
|
---|
[395] | 230 | %endif
|
---|
[492] | 231 |
|
---|