[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 |
---|
[526] | 6 | ; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team. |
---|
[376] | 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: |
---|
[553] | 31 | sti ; Enable interrupts |
---|
[592] | 32 | %ifdef CLD_NEEDED |
---|
[553] | 33 | cld ; String instructions to increment pointers |
---|
[592] | 34 | %endif |
---|
[567] | 35 | %ifdef MODULE_VERY_LATE_INIT |
---|
[561] | 36 | LOAD_BDA_SEGMENT_TO ds, ax ; Load BDA segment (zero) to DS |
---|
| 37 | les ax, [TEMPORARY_VECTOR_FOR_SYSTEM_INT13h*4] |
---|
| 38 | mov [BIOS_DISK_INTERRUPT_13h*4], ax |
---|
| 39 | mov [BIOS_DISK_INTERRUPT_13h*4+2], es |
---|
| 40 | push ds ; BDA segment (zero)... |
---|
| 41 | pop es ; ...to ES |
---|
| 42 | %else |
---|
[560] | 43 | LOAD_BDA_SEGMENT_TO es, ax ; Load BDA segment (zero) to ES |
---|
[556] | 44 | %endif |
---|
[392] | 45 | ; Fall to .PrepareBootLoaderStack |
---|
[243] | 46 | |
---|
[392] | 47 | |
---|
[243] | 48 | ;-------------------------------------------------------------------- |
---|
[392] | 49 | ; Drive detection and boot menu use lots of stack so it is |
---|
| 50 | ; wise to relocate stack. Otherwise something important from |
---|
| 51 | ; interrupt vectors are likely corrupted, likely our own DPTs if |
---|
| 52 | ; they are located to 30:0h. |
---|
| 53 | ; |
---|
| 54 | ; .PrepareBootLoaderStack |
---|
[243] | 55 | ; Parameters: |
---|
| 56 | ; ES: BDA and interrupt vector segment (zero) |
---|
| 57 | ; Returns: |
---|
| 58 | ; Never returns (loads operating system) |
---|
| 59 | ;-------------------------------------------------------------------- |
---|
[392] | 60 | .PrepareBootLoaderStack: |
---|
[243] | 61 | STORE_POST_STACK_POINTER |
---|
| 62 | SWITCH_TO_BOOT_MENU_STACK |
---|
| 63 | ; Fall to .InitializeDisplay |
---|
| 64 | |
---|
[392] | 65 | |
---|
[243] | 66 | ;-------------------------------------------------------------------- |
---|
| 67 | ; .InitializeDisplay |
---|
| 68 | ; Parameters: |
---|
[392] | 69 | ; ES: BDA and interrupt vector segment (zero) |
---|
[243] | 70 | ; Returns: |
---|
| 71 | ; Never returns (loads operating system) |
---|
| 72 | ;-------------------------------------------------------------------- |
---|
| 73 | .InitializeDisplay: |
---|
| 74 | ; Change display mode if necessary |
---|
| 75 | mov ax, [cs:ROMVARS.wDisplayMode] ; AH 00h = Set Video Mode |
---|
| 76 | cmp al, DEFAULT_TEXT_MODE |
---|
| 77 | je SHORT .InitializeDisplayLibrary |
---|
| 78 | int BIOS_VIDEO_INTERRUPT_10h |
---|
| 79 | .InitializeDisplayLibrary: |
---|
[392] | 80 | call DetectPrint_InitializeDisplayContext |
---|
| 81 | ; Fall to .InitializeBiosAndDetectDrives |
---|
[243] | 82 | |
---|
[392] | 83 | |
---|
[243] | 84 | ;-------------------------------------------------------------------- |
---|
[392] | 85 | ; .InitializeBiosAndDetectDrives |
---|
[243] | 86 | ; Parameters: |
---|
[392] | 87 | ; ES: BDA and interrupt vector segment (zero) |
---|
[243] | 88 | ; Returns: |
---|
[392] | 89 | ; DS: RAMVARS segment |
---|
[243] | 90 | ;-------------------------------------------------------------------- |
---|
[555] | 91 | .InitializeBiosAndDetectDrives: |
---|
[413] | 92 | call Initialize_AndDetectDrives |
---|
| 93 | |
---|
| 94 | %ifdef MODULE_HOTKEYS |
---|
[547] | 95 | ; Last hard drive might have scrolled Hotkey Bar out of screen. |
---|
| 96 | ; We want to display it during wait. |
---|
[599] | 97 | ;call HotkeyBar_UpdateDuringDriveDetection |
---|
[547] | 98 | |
---|
[413] | 99 | .WaitUntilTimeToCloseHotkeyBar: |
---|
| 100 | call TimerTicks_ReadFromBdaToAX |
---|
[524] | 101 | sub ax, [es:BOOTVARS.hotkeyVars+HOTKEYVARS.wTimeWhenDisplayed] |
---|
| 102 | cmp ax, MIN_TIME_TO_DISPLAY_HOTKEY_BAR |
---|
[413] | 103 | jb SHORT .WaitUntilTimeToCloseHotkeyBar |
---|
[599] | 104 | |
---|
| 105 | ; Restore system timer tick handler since hotkeys are no longer needed |
---|
| 106 | cli |
---|
| 107 | mov ax, [es:BOOTVARS.hotkeyVars+HOTKEYVARS.fpPrevTimerHandler] |
---|
[604] | 108 | mov [es:BIOS_SYSTEM_TIMER_TICK_INTERRUPT_08h*4], ax |
---|
[599] | 109 | mov ax, [es:BOOTVARS.hotkeyVars+HOTKEYVARS.fpPrevTimerHandler+2] |
---|
[604] | 110 | mov [es:BIOS_SYSTEM_TIMER_TICK_INTERRUPT_08h*4+2], ax |
---|
[599] | 111 | sti |
---|
[413] | 112 | %endif |
---|
[555] | 113 | ; Fall to .ResetAllDrives |
---|
| 114 | |
---|
| 115 | |
---|
| 116 | ;-------------------------------------------------------------------- |
---|
| 117 | ; .ResetAllDrives |
---|
| 118 | ; Parameters: |
---|
| 119 | ; DS: RAMVARS segment |
---|
| 120 | ; ES: BDA and interrupt vector segment (zero) |
---|
| 121 | ; Returns: |
---|
| 122 | ; Nothing |
---|
| 123 | ;-------------------------------------------------------------------- |
---|
| 124 | .ResetAllDrives: |
---|
| 125 | ; Reset all drives in the system, not just our drives. |
---|
| 126 | xor ax, ax ; Disk Controller Reset |
---|
| 127 | mov dl, 80h ; Reset all hard drives and floppy drives |
---|
| 128 | int BIOS_DISK_INTERRUPT_13h |
---|
[392] | 129 | ; Fall to SelectDriveToBootFrom |
---|
[243] | 130 | |
---|
[392] | 131 | |
---|
[243] | 132 | ;-------------------------------------------------------------------- |
---|
[392] | 133 | ; SelectDriveToBootFrom |
---|
[243] | 134 | ; Parameters: |
---|
| 135 | ; DS: RAMVARS segment |
---|
[392] | 136 | ; ES: BDA and interrupt vector segment (zero) |
---|
[243] | 137 | ; Returns: |
---|
| 138 | ; Never returns (loads operating system) |
---|
| 139 | ;-------------------------------------------------------------------- |
---|
[492] | 140 | ; The following macro could be easily inlined below. Why a macro? Depending on the combination |
---|
| 141 | ; of MODULE_HOTKEYS or MODULE_BOOT_MENU, this code needs to either come before or after the |
---|
[505] | 142 | ; call to the boot menu. |
---|
[492] | 143 | ; |
---|
| 144 | %macro TRY_TO_BOOT_DL_AND_DH_DRIVES 0 |
---|
| 145 | push dx ; it's OK if this is left on the stack, if we are |
---|
[505] | 146 | ; successful, the following call does not return |
---|
[528] | 147 | call BootSector_TryToLoadFromDriveDL_AndBoot |
---|
[492] | 148 | pop dx |
---|
| 149 | mov dl, dh |
---|
[528] | 150 | call BootSector_TryToLoadFromDriveDL_AndBoot |
---|
[492] | 151 | %endmacro |
---|
[505] | 152 | |
---|
[528] | 153 | |
---|
| 154 | SelectDriveToBootFrom: ; Function starts here |
---|
[395] | 155 | %ifdef MODULE_HOTKEYS |
---|
[528] | 156 | mov al, [es:BOOTVARS.hotkeyVars+HOTKEYVARS.bScancode] |
---|
[492] | 157 | cmp al, ROM_BOOT_HOTKEY_SCANCODE |
---|
[528] | 158 | je SHORT .RomBoot ; CF clear so ROM boot |
---|
[392] | 159 | %ifdef MODULE_BOOT_MENU |
---|
[492] | 160 | cmp al, BOOT_MENU_HOTKEY_SCANCODE |
---|
[528] | 161 | je SHORT .BootMenu |
---|
| 162 | %endif ; MODULE_BOOT_MENU |
---|
| 163 | |
---|
| 164 | .TryUsingHotKeysCode: |
---|
[492] | 165 | call HotkeyBar_GetBootDriveNumbersToDX |
---|
[528] | 166 | call DriveXlate_SetDriveToSwap ; Enable primary boot device translation |
---|
| 167 | xchg dl, dh |
---|
| 168 | call DriveXlate_SetDriveToSwap ; Enable secondary boot device translation |
---|
| 169 | xchg dl, dh |
---|
[529] | 170 | call DriveXlate_ToOrBack ; Translate now so boot device will appear as 00h or 80h to OS |
---|
[492] | 171 | TRY_TO_BOOT_DL_AND_DH_DRIVES |
---|
| 172 | ;; falls through to boot menu, if it is present. If not present, falls through to rom boot. |
---|
[505] | 173 | %endif ; MODULE_HOTKEYS |
---|
[392] | 174 | |
---|
[528] | 175 | |
---|
[492] | 176 | %ifdef MODULE_BOOT_MENU |
---|
[505] | 177 | .BootMenu: |
---|
[492] | 178 | call BootMenu_DisplayAndReturnDriveInDLRomBootClearCF |
---|
[528] | 179 | jnc SHORT .RomBoot ; CF clear so ROM boot |
---|
[392] | 180 | |
---|
[528] | 181 | call DriveXlate_Reset |
---|
| 182 | %ifdef MODULE_HOTKEYS |
---|
| 183 | jmp SHORT .TryUsingHotKeysCode ; Selected drive stored as hotkey |
---|
| 184 | %else ; Boot menu without hotkeys, secondary boot drive is always 00h or 80h |
---|
[492] | 185 | mov dh, dl ; Setup for secondary drive |
---|
[505] | 186 | not dh ; Floppy goes to HD, or vice versa |
---|
| 187 | and dh, 80h ; Go to first drive of the floppy or HD set |
---|
[528] | 188 | call DriveXlate_SetDriveToSwap |
---|
| 189 | call DriveXlate_ToOrBack |
---|
| 190 | TRY_TO_BOOT_DL_AND_DH_DRIVES |
---|
| 191 | jmp SHORT .BootMenu ; Show boot menu again |
---|
| 192 | %endif ; MODULE_HOTKEYS |
---|
[398] | 193 | |
---|
[505] | 194 | %endif ; MODULE_BOOT_MENU |
---|
[392] | 195 | |
---|
[528] | 196 | ; No hotkeys and no boot menu means fixed "A then C" boot order |
---|
[505] | 197 | %ifndef MODULE_HOTKEYS OR MODULE_BOOT_MENU |
---|
[529] | 198 | xor dl, dl ; Try to boot from Floppy Drive A |
---|
[528] | 199 | call BootSector_TryToLoadFromDriveDL_AndBoot |
---|
[529] | 200 | mov dl, 80h ; Try to boot from Hard Drive C |
---|
[528] | 201 | call BootSector_TryToLoadFromDriveDL_AndBoot |
---|
[386] | 202 | %endif |
---|
[243] | 203 | |
---|
[493] | 204 | .RomBoot: |
---|
| 205 | %ifdef MODULE_DRIVEXLATE |
---|
| 206 | call DriveXlate_Reset ; Clean up any drive mappings before Rom Boot |
---|
| 207 | %endif |
---|
[597] | 208 | stc |
---|
| 209 | ;; fall through to Int19h_JumpToBootSectorInESBXOrRomBoot |
---|
[392] | 210 | |
---|
[243] | 211 | ;-------------------------------------------------------------------- |
---|
[597] | 212 | ; Int19h_JumpToBootSectorInESBXOrRomBoot |
---|
[243] | 213 | ; |
---|
| 214 | ; Switches back to the POST stack, clears the DS and ES registers, |
---|
| 215 | ; and either jumps to the MBR (Master Boot Record) that was just read, |
---|
[601] | 216 | ; or calls the ROM's boot routine on interrupt 18h. |
---|
[243] | 217 | ; |
---|
| 218 | ; Parameters: |
---|
| 219 | ; DL: Drive to boot from (translated, 00h or 80h) |
---|
[597] | 220 | ; CF: Clear for Boot Sector Boot |
---|
| 221 | ; Set for ROM Boot |
---|
| 222 | ; ES:BX: (if CF clear) Ptr to boot sector (ES = zero) |
---|
[243] | 223 | ; |
---|
| 224 | ; Returns: |
---|
| 225 | ; Never returns |
---|
| 226 | ;-------------------------------------------------------------------- |
---|
[597] | 227 | Int19h_JumpToBootSectorInESBXOrRomBoot: |
---|
| 228 | mov ax, es ; Clear AX. NOTE: can't use XOR (LOAD_BDA_SEGMENT_TO) as it impacts CF |
---|
[243] | 229 | SWITCH_BACK_TO_POST_STACK |
---|
| 230 | |
---|
| 231 | ; clear segment registers before boot sector or rom call |
---|
[597] | 232 | Int19h_JumpToBootSectorInESBXOrRomBootWithoutStackChange: |
---|
| 233 | mov ax, es ; Clear AX and preserve CF |
---|
[505] | 234 | mov ds, ax |
---|
[243] | 235 | %ifdef USE_386 |
---|
| 236 | mov fs, ax |
---|
| 237 | mov gs, ax |
---|
| 238 | %endif |
---|
[597] | 239 | jc SHORT .RomBoot |
---|
[243] | 240 | |
---|
| 241 | ; jump to boot sector |
---|
[597] | 242 | push es ; sgment address for MBR |
---|
[243] | 243 | push bx ; offset address for MBR |
---|
| 244 | retf ; NOTE: DL is set to the drive number |
---|
| 245 | |
---|
| 246 | ; Boot by calling INT 18h (ROM Basic of ROM DOS) |
---|
[596] | 247 | .RomBoot: |
---|
[505] | 248 | int BIOS_BOOT_FAILURE_INTERRUPT_18h ; Never returns |
---|