[88] | 1 | ; Project name : XTIDE Universal BIOS |
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[3] | 2 | ; Description : Defines for BOOTVARS struct used by boot menu |
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| 3 | ; and drive initialization. |
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[376] | 4 | |
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| 5 | ; |
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| 6 | ; XTIDE Universal BIOS and Associated Tools |
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| 7 | ; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2012 by XTIDE Universal BIOS Team. |
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| 8 | ; |
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| 9 | ; This program is free software; you can redistribute it and/or modify |
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| 10 | ; it under the terms of the GNU General Public License as published by |
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| 11 | ; the Free Software Foundation; either version 2 of the License, or |
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| 12 | ; (at your option) any later version. |
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| 13 | ; |
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| 14 | ; This program is distributed in the hope that it will be useful, |
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| 15 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 16 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 17 | ; GNU General Public License for more details. |
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| 18 | ; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html |
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| 19 | ; |
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| 20 | |
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[3] | 21 | %ifndef BOOTVARS_INC |
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| 22 | %define BOOTVARS_INC |
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| 23 | |
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| 24 | |
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[96] | 25 | BOOT_READ_RETRY_TIMES EQU 3 |
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| 26 | |
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| 27 | |
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[3] | 28 | |
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[294] | 29 | ; Pre-boot variables. These do not exist after successful boot to OS. |
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[3] | 30 | ; Segment is always 0000h, same as BDA segment |
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| 31 | struc BOOTVARS |
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[221] | 32 | resb 7C00h |
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[3] | 33 | .rgbAtaInfo: ; 7C00h, ATA Information for drive detection |
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| 34 | .rgbBootSect resb 512 ; 7C00h, Boot sector |
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[221] | 35 | resb 256 ; Boot Menu stack |
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| 36 | .rgbMnuStack: |
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| 37 | .dwPostStack resb 4 ; POST stack pointer when entering INT 19h |
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| 38 | .rgBootNfo: ; Array containing BOOTNFO structs |
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[3] | 39 | endstruc |
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| 40 | |
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| 41 | |
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[121] | 42 | ;-------------------------------------------------------------------- |
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| 43 | ; Stores POST stack pointer to BOOTVARS. |
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| 44 | ; |
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| 45 | ; STORE_POST_STACK_POINTER |
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| 46 | ; Parameters: |
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[243] | 47 | ; ES: BDA and Interrupt Vector segment (zero) |
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[121] | 48 | ; Returns: |
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| 49 | ; Nothing |
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| 50 | ; Corrupts registers: |
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| 51 | ; Nothing |
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| 52 | ;-------------------------------------------------------------------- |
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| 53 | %macro STORE_POST_STACK_POINTER 0 |
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[243] | 54 | mov [es:BOOTVARS.dwPostStack], sp |
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| 55 | mov [es:BOOTVARS.dwPostStack+2], ss |
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[121] | 56 | %endmacro |
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| 57 | |
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| 58 | |
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| 59 | ;-------------------------------------------------------------------- |
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| 60 | ; Initializes stack for boot menu usage. |
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| 61 | ; POST stack is not large enough when DPTs are stored to 30:0h. |
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| 62 | ; |
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| 63 | ; Note regarding LOAD_BDA_SEGMENT_TO: If you force the use of SP |
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| 64 | ; then you also have to unconditionally enable the CLI/STI pair. |
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| 65 | ; The reason for this is that only some buggy 808x CPU:s need the |
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| 66 | ; CLI/STI instruction pair when changing stacks. Other CPU:s disable |
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| 67 | ; interrupts automatically when SS is modified for the duration of |
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| 68 | ; the immediately following instruction to give time to change SP. |
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| 69 | ; |
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| 70 | ; SWITCH_TO_BOOT_MENU_STACK |
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| 71 | ; Parameters: |
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| 72 | ; Nothing |
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| 73 | ; Returns: |
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| 74 | ; SS:SP: Pointer to top of Boot Menu stack |
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| 75 | ; Corrupts registers: |
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| 76 | ; Nothing |
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| 77 | ;-------------------------------------------------------------------- |
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| 78 | %macro SWITCH_TO_BOOT_MENU_STACK 0 |
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| 79 | %ifndef USE_186 |
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| 80 | cli ; Disable interrupts |
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| 81 | %endif |
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| 82 | LOAD_BDA_SEGMENT_TO ss, sp |
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| 83 | mov sp, BOOTVARS.rgbMnuStack ; Load offset to stack |
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| 84 | %ifndef USE_186 |
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| 85 | sti ; Enable interrupts |
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| 86 | %endif |
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| 87 | %endmacro |
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| 88 | |
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| 89 | |
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| 90 | ;-------------------------------------------------------------------- |
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| 91 | ; Restores SS and SP to initial boot loader values. |
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| 92 | ; |
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[243] | 93 | ; Note! Must return with AX=0 and CF preserved. |
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| 94 | ; See Int19hMenu_JumpToBootSector_or_RomBoot. |
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[121] | 95 | ; |
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| 96 | ; SWITCH_BACK_TO_POST_STACK |
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| 97 | ; Parameters: |
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[243] | 98 | ; AX: BDA and Interrupt Vector segment (zero) |
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[121] | 99 | ; Returns: |
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| 100 | ; SS:SP: Ptr to POST stack |
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| 101 | ; Corrupts registers: |
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[243] | 102 | ; Nothing (not even FLAGS) |
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[121] | 103 | ;-------------------------------------------------------------------- |
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| 104 | %macro SWITCH_BACK_TO_POST_STACK 0 |
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| 105 | %ifndef USE_386 |
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[243] | 106 | cli |
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| 107 | mov ss, ax |
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[121] | 108 | mov sp, [ss:BOOTVARS.dwPostStack] |
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| 109 | mov ss, [ss:BOOTVARS.dwPostStack+2] |
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[243] | 110 | sti |
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[121] | 111 | %else |
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[243] | 112 | mov ss, ax |
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[121] | 113 | lss sp, [ss:BOOTVARS.dwPostStack] |
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[294] | 114 | %endif |
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[121] | 115 | %endmacro |
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| 116 | |
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| 117 | |
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[3] | 118 | %endif ; BOOTVARS_INC |
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